However, whether and how PD-L1+ TEVs mediate αPD-L1 therapy resistance is unknown. Here, we show that PD-L1+ TEVs substantially decoy αPD-L1 and that TEV-bound αPD-L1 is more rapidly cleared by macrophages, causing insufficient blockade of tumor PD-L1 and subsequent αPD-L1 therapy resistance. Inhibition of endogenous production of TEVs by Rab27a or Coro1a knockout reverses αPD-L1 therapy resistance. Either an increased αPD-L1 dose or macrophage depletion mediated by the clinical drug pexidartinib abolishes αPD-L1 therapy resistance. Moreover, in the treatment cycle with the same total treatment dose of αPD-L1, high-dose and low-frequency treatment had better antitumor effects than low-dose and high-frequency treatment, induced stronger antitumor immune memory, and eliminated αPD-L1 therapy resistance. Notably, in humanized immune system mice with human xenograft tumors, both increased αPD-L1 dose and high-dose and low-frequency treatment enhanced the antitumor effects of αPD-L1. Furthermore, increased doses of αPD-L1 and αPD-1 had comparable antitumor effects, but αPD-L1 amplified fewer PD-1+ Treg cells, which are responsible for tumor hyperprogression. Altogether, our results reveal a TEV-mediated mechanism of αPD-L1-specific therapy resistance, thus providing promising strategies to improve αPD-L1 efficacy.PD-L1 The application of immune checkpoint blockade, including anti-PD-1 and anti-PD-L1 antibodies (αPD-1 and αPD-L1), has led to a major revolution in tumor immunotherapy. Although αPD-1 and αPD-L1 show excellent efficacy in various tumor types, even in patients with advanced tumors , only 10+ T cells and facilitates tumor growth [Extracellular vesicles (EVs) are mainly divided into two categories: ectosomes and exosomes. Ectosomes (50–1000 nm in diameter) are vesicles produced by direct outward budding of the plasma membrane. Exosomes (30–150 nm in diameter) are generated from the endosomal pathway. EVs contain large numbers of proteins, nucleic acids, lipids and metabolites from their parent cells and are essential for communication between cells . PD-L1 hr growth . TEV PD-r growth . TEV PD-r growth . These fr growth . SimilarPD-1 has two naturally occurring ligands, PD-L1 and PD-L2, that provide inhibitory signals to T cells via PD-1 . αPD-1 bHere, we found that TEVs can efficiently decoy αPD-L1 via PD-L1. TEV-bound αPD-L1 is more readily phagocytized by macrophages and then more rapidly degraded by lysosomes. In this way, TEVs consume large amounts of αPD-L1, leading to insufficient αPD-L1 to block PD-L1 on tumor cells, thereby mediating αPD-L1 therapy resistance.CV) that occupied all PD-L1 on 1 × 105 MC38 and PC3 cells was approximately 250 ng  did not affect the binding of αPD-L1 and PD-L1 to MC38 cells  was used to block PD-L1 on MC38 cells, the addition of MC38-EVs no longer increased the αPD-L1-free PD-L1 on MC38 cells  and human PC3 prostate cancer cells (PC3-EVs) that have been reported to contain high levels of PD-L1. These EVs showed typical exosome-like morphology  of αPD-L1, respectively. However, EVs from tumor tissues (EVs-TT) of these mice bound approximately 0.95 ± 0.20, 1.69 ± 0.16 and 2.51 ± 0.14 μg  of αPD-L1, respectively, which was remarkably high. In addition, the PD-L1 levels of Circ-EVs were positively correlated with those of EVs-TT  along with the decreased IFN-γ+CD8+ and Ki-67+CD8+ T cells in the TTs of the mice that received MC38-EVs but not MC38 Pdl1−/−-EVs  from mice with 1-, 2- and 4-week MC38 tumors bound approximately 0.04 ± 0.02, 0.12 ± 0.01 and 0.16 ± 0.01 μg  with impaired TEV secretion , which release reduced TEVs [Rab27a−/− tumor-bearing mice, αPD-L1 notably inhibited MC38 Coro1a−/− but not MC38 tumor growth at the same dose  was used, the difference in growth between MC38 tumors and MC38 Rab27a−/− or MC38 Coro1a−/− tumors was completely eliminated , peripheral blood and spleen were observed in the tumor-bearing mice receiving high-dose and low-frequency αPD-L1 treatment , an inhibitor of colony-stimulating factor 1 receptor (CSF-1R), markedly reduced the numbers of peripheral monocytes and liver macrophages  of αPD-L1. We also detected PD-L1 on the EVs-TT of another 3 lung cancer patients  of αPD-L1. Then, we established a PC3 tumor model in nonobese diabetes/severe combined immune deficiency (NOD/SCID) mice, and in these tumor-carrying mice, EVs-TT #3 obviously decreased the binding of αPD-L1 and tumor PD-L1  cells, thereby leading to hyperprogression of cancer [+ Treg cells. We indeed found in the TRAMP-C2 tumor-bearing mice that αPD-1Exe treatment induced more Ki-67+PD-1+ Treg cells than αPD-L1Exe treatment . The mice were housed in a specific pathogen-free facility, and the experimental protocols were approved by the Animal Care and Use Committee of the First Affiliated Hospital of Zhejiang University.C57BL/6 J and NOD/SCID female mice aged 6-8 weeks were purchased from Joint Ventures Sipper BK Experimental Animal Co. . 2.PC3 cells, MC38 cells and TRAMP-C2 cells were purchased from the Chinese Academy of Sciences Institute . PC3, MC38 and TRAMP-C2 cells were cultured in DMEM with 10% exosome-depleted fetal bovine serum (FBS)  and 1% penicillin/streptomycin . PMs were collected 3 days after the intraperitoneal injection of C57BL/6 J mice with thioglycolate . PMs were cultured in RPMI-1640 with 10% FBS and 1% penicillin/streptomycin. All cells were cultured at 37 °C with 5% COg for 10 min, 2000 × g for 20 min and 10,000 × g for 30 min at 4 °C. Then, the MV pellets were resuspended in sterile PBS, and the supernatants were passed through 0.22 μm syringe filters  and collected in 35 ml ultracentrifuge tubes . The EVs were concentrated using ultracentrifugation with a SW32Ti rotor  at 100,000 × g for 70 min at 4 °C. Subsequently, the EV pellets were resuspended in sterile PBS. The protein contents of the EVs were quantified by using a BCA protein assay kit in the absence of detergent (Thermo Fisher Scientific).PC3, MC38 and TRAMP-C2 cells were plated at a density of 3 million cells per 15-cm plate (Corning 430599) and cultured for 48 h, and the media from 10 plates were collected. For PC3-EV, MC38-EV and B16-EV separation, cell culture supernatants were centrifuged at 300 × A total of 5 μg of PC3-EVs or MC38-EVs was diluted in PBS and placed on 200-mesh carbon-coated copper grids at room temperature (RT) for 2 min. The excess suspension was removed using filter paper. Then, the PC3-EVs or MC38-EVs were negatively stained with uranyl acetate at RT for 5 min, washed twice with PBS, dried and examined under an FEI Tecnai T10 EM  operating at 100 kV.g for 10 min. Samples were separated by 10% SDS-polyacrylamide gel electrophoresis and transferred to PVDF membranes (Millipore), which were blocked with 5% milk for 1.5 h, incubated with the corresponding primary antibodies at 4 °C overnight, and then incubated with secondary antibodies at RT for 2 h. An Enhanced Chemiluminescence Kit  was used to detect the bands. The antibodies used and the corresponding dilutions are listed in Supplementary Table Equal amounts of cell or tissue lysate or EV proteins were resuspended in 5 × SDS loading buffer, incubated at 100 °C for 5 min, and centrifuged at 12,000 × The number and size distribution of EVs were analyzed using a NanoSight NS300 . EVs were resuspended in PBS for analysis. For recordings, samples were pumped automatically into a chamber at a constant flow rate using the Malvern NanoSight syringe pump system. The camera level was adjusted to 14, and three 30’ captures per sample were recorded. For analysis of the recordings, the detection threshold was set to 5, and the NTA3.3 Suite Software was used for analysis.g or 3500 × g for 5 min at 4 °C, and then incubated with the corresponding fluorescence-conjugated primary antibodies in 100 μl of PBS at predetermined saturating concentrations for 20 min at RT. After two washes in PBS, the cells or beads were analyzed on an ACEA NovoCyte flow cytometer . For intracellular staining, cells were stimulated with PMA , ionomycin , and brefeldin A solution  at 37 °C for 4 h and then subjected to intracellular staining. The data were analyzed using FlowJo software , and the antibodies used and the corresponding dilutions are listed in Supplementary Table Cells or EVs incubated with 4-μm aldehyde sulfate beads (Thermo Fisher Scientific) were washed in PBS with 1% BSA, collected by centrifugation at 400 × −1 puromycin. Live cells were sorted using a Beckman Coulter DxFLEX flow cytometer (Beckman Coulter). After sorting, single cells were cultured in 96-well plates. The Rab27a or PD-L1 knockout efficiency was confirmed by western blotting or flow cytometry. Selected MC38 cells with unchanged Rab27a or PD-L1 expression were used as controls.For depletion of Rab27a or PD-L1 in MC38 cells, the guide RNA plasmid . Human CD8+ T cells were isolated from PBMCs of healthy donors with a Human CD8+ T-Cell Enrichment Kit (StemCell). A total of 1 × 106 CD8+ T cells were labeled with CFSE (Thermo Fisher Scientific) at 5 μM. The cells were then incubated at 37 °C for 5 min, and the reaction was stopped by adding an equal volume of RPMI-1640 with 10% FBS. Unstimulated CFSE-labeled cells served as a nondividing control. Both mouse and human CD8+ T cells (1 × 106 ml−1) were stimulated with αCD3 and αCD28  for 24 h and then incubated with MC38 and PC3 cells alone (2.5 × 105 ml−1) or MC38 and PC3 cells plus the corresponding TEVs with or without αPD-L1  for 48 h.Mouse CD8+ Treg cells were isolated from splenocytes and peripheral lymph nodes in Foxp3GFP transgenic mice and sorted by a Beckman Coulter DxFLEX flow cytometer (Beckman Coulter). A total of 1 × 106 PD-1+ Treg cells were labeled with 1 μM CellTraceTM Far Red (Thermo Fisher Scientific). Then, the reaction was stopped by adding an equal volume of RPMI-1640 with 10% FBS, and the cells (3 × 105 ml−1) were stimulated with complete RPMI 1640 medium containing 1 ng ml−1 PMA, 200 ng ml−1 ionomycin , and 4000 U ml−1 murine IL-2  in the presence of 5 μg ml−1 recombinant mouse PD-L2 (BioLegend) for 72 h.PD-12SO4, followed by measurement of the absorbance at 450 nm. The concentration of αPD-L1 on the surface of EVs was calculated based on the linear range of the ELISA data. Serial dilutions of biotinylated αPD-L1 (Thermo Fisher Scientific) were used to generate a standard curve. The results of the standard curve demonstrated that the established ELISA exhibited a reliable linear detection range from 3 to 800 ng ml−1.For determination of the αPD-L1-binding ability of EVs, 96-well ELISA plates were coated with αCD63, αCD81 and αCD9 at 4 °C overnight . Free binding sites were blocked with 100 μl of blocking buffer for 1 h at RT. Then, serum samples or EVs-TT (50 μl per sample) were added to duplicate wells, followed by incubation overnight at 4 °C. The plates were washed, and biotinylated αPD-L1 (Thermo Fisher Scientific) or biotin αRat IgG (BioLegend) was added to each well and incubated for 1 h at RT. Then, streptavidin-HRP (BioLegend) diluted in 100 μl of PBS was added and incubated for 1 h at RT. The reaction was developed with TMB and blocked with 2 M HRab27a−/−, MC38 Coro1a−/−, TRAMP-C2 and TRAMP-C2 Rab27a−/− cells (2 × 106) were resuspended in 200 μl of PBS and subcutaneously implanted into the right flank of C57BL/6 female mice on Day 0. PC3 cancer cells (5 × 106) were injected subcutaneously into NOD-SCID mice on Day 0. When tumors reached an average of 100–200 mm3, as calculated with the formula volume = (width2 × length) 2−1, the mice were randomized into different treatment groups. For analysis of the treatment difference between αPDL1 and αPD-1, 10 μg of αPD-1 (BioLegend) or αPD-L1 was injected intravenously into mice every 2 days. For determination of the effect on TEVs binding αPD-L1 in vivo, the mice with TRAMP-C2, TRAMP-C2 Rab27a−/−, MC38, MC38 Rab27a−/− or MC38 Coro1a−/− tumors were intravenously injected with 10 or 30 μg of αPD-L1 every 2 days. For determination of whether TEV-bound αPD-L1 is eliminated by macrophages, the mice with MC38 or MC38 Rab27a−/− tumors were intravenously injected with 10 μg of αPD-L1 with or without intraperitoneal injection of 20 μg of PLX3397  or with or without intravenous injection of 50 μl Clodrosomes  every 2 days when the tumor size reached 100–200 mm3. For the humanized tumor model, NOD-SCID mice were intratumorally injected with preactivated human PBMCs (1 × 106) when the tumor size reached 80–100 mm3. Two days later, the mice were intravenously injected with αPD-L1, with or without 20 μg PC3-EVs. In some experiments, the mice with TRAMP-C2 tumors were intravenously injected with 20 μg of αCTLA-4 (BioLegend) and 30 μg of αPD-L1 or αPD-1 every 2 days when the tumor size reached 80–100 mm3. At the experimental end point, livers, spleens and tumors were excised for subsequent histologic analysis or processed immediately for flow cytometry analyses, and serum was collected for ELISAs.For construction of subcutaneous tumor models, MC38, MC38 Murine tumor tissue sections were routinely deparaffinized and rehydrated, followed by antigen retrieval using 10 mM sodium citrate buffer (pH 6.0). After the samples were blocked with 1× blocking solution at 37 °C for 1 h, they were incubated with mouse αRat IgG2a (BioLegend) and rabbit αPD-L1  overnight at 4 °C. Then, PLA was performed with Duolink In situ reagents  according to the manufacturer’s instructions. Then, the samples were imaged using Olympus FluoView version 1.4a software . Images of cells and sections were acquired, and positively stained areas were analyzed by ImageJ software .αPD-L1 was labeled with Protein Labeling Kits (Thermo Fisher Scientific) according to the manufacturer’s instructions. Then, 10 μg of labeled αPD-L1 or 10 μg of labeled αPD-L1 and 20 μg of TEV mixture were intravenously injected into mice. 12 h later, the mice were sacrificed, and the brain, heart, lungs, liver, spleen, kidneys, gut and tumor were collected. The labeled αPD-L1 was imaged by an IVIS . The background and autofluorescence were defined according to the supernatant negative controls and subtracted from the images using the Image-Math function. In addition, the exposure conditions  were identical for all measurements within each experiment. Total measurements were obtained under the same conditions for all experimental groups.The murine PMs were cultured overnight on glass coverslips and then treated with lysosome inhibitors for 24 h. Then, the cells were coincubated with labeled αPD-L1 or TEV-bound αPD-L1 for another 2 h. After being washed three times with PBS, the cells were fixed with precooled methyl alcohol for 10 min at −20 °C and then permeabilized with 0.1% Triton X-100 for 10 min at RT. After the cells were blocked with 5% BSA and 3% goat serum in PBS, they were incubated with LAMP1 antibodies  overnight at 4 °C in blocking buffer. The following day, after three washes in PBS, the cells were incubated with DyLight 488-labeled secondary antibodies  for 30 min at RT and washed in PBS. Finally, nuclei were stained with DAPI (Thermo Fisher Scientific). Liver and spleen tissues were embedded in Tissue-Tek™ CRYO-O.C.T. (Thermo Fisher Scientific) and processed to obtain 5 μm sections. Then, the tissue sections were stained with mouse F4/80 antibodies (Abcam) at 4 °C overnight followed by staining with DyLight 488-labeled secondary antibodies (Multi Sciences Biotech) for 1 h at 4 °C. The nuclei were stained with DAPI (Thermo Fisher Scientific) for 20 min at RT. The stained sections were imaged using an Olympus IX83-FV3000 confocal microscope (Olympus). Images were analyzed with ImageJ software (NIH).t test was used to compare the differences between two groups, and one-way ANOVA followed by Tukey’s test was used to compare the differences among multiple groups. The Spearman rank-order correlation test was used for correlation analysis. A difference was considered significant if the P value was < 0.05.All statistical analyses were performed using GraphPad Prism 8.0 . All data are expressed as the mean ± s.d. An unpaired two-tailed Student’s Supplementary Information


SO42– anions were found to preferentially accumulate nearthe interface at an open circuit potential (OCP), creating an electricalfield that orients water molecules below the interface, as revealedby the increased intensity of the O–H stretching peak of H-bondedwater. No such increase is observed with NH4Cl at the OCP.The intensity of the dangling O–H bond stretching peak howeverremains largely unchanged. The degree of orientation of the watermolecules as well as the electrical double layer strength increasedfurther when positive voltages are applied. Negative voltages on theother hand produced only small changes in the intensity of the H-bondedwater peaks but affected the intensity and frequency of dangling O–Hbond peaks. The TOC figure is an oversimplified representation ofthe system in this work.The structure of interfacial water near suspended grapheneelectrodesin contact with aqueous solutions of Na To improve our understanding of the electricaldouble layer (EDL) at the graphene–electrolyte interface withoutinterference from the substrate, we used suspended graphene, whichalso separates the solution from the ambient air.The graphene–electrolyte interfaceplays an important rolein many applications and technological fields, such as electrocatalysis,energy storage, water desalination,16 witha specific affinity for cations due to their interactionswith graphene defects and π-orbitals.18 In recent work, an affinity for anions, including OH–, Cl–, and SO42–,has been proposed.21 The ions are the main factors in the formation ofthe EDL, which is strongly influenced by the differential segregationof the electrolyte ions to the interface, driven by various physicaland chemical forces. One arises from the image charge, where the abruptchange of dielectric properties across the solution–electrodeinterface leads to polarization effects that can be described by imagecharges outside the solution. This effect however does not lead todifferential segregation here, as both cations and ions are affectedalike. However, image charge interactions may assist the ion segregationat the interface in the presence of other mechanisms that break thesymmetry between anions and cations. Another is the segregation ofions out of the solution due to the interplay of enthalpic and entropicforces in ion solvation23 and by the differentdisruption of the H-bonding structure of water near ions in the bulkand interface. A third driver is the formation of bonds between ionsand the electrode, of covalent, ionic, or van der Waals character.Finally, external forces such as the applied bias also play a crucialrole. The purpose of this work is to obtain a molecular level understandingof these driving forces and the structure of the electric double layerthey create. As we show below, the combination of Raman spectroscopy,sum frequency vibrational spectroscopy (SFVS), and Kelvin probe forcemicroscopy (KPFM), together with the use of suspended graphene electrodes,provides a unique perspective and insight for such studies.Graphene isnormally assumed to be hydrophobic,2SO4, (NH4)2SO4, and NH4Cl, were chosen becauseof their distinctive adsorption behavior at the air/water interface.24 Through Raman measurements, we found that thedoping of graphene by electrolyte species is very small at bulk concentrationsbelow 10 mM and thus can be ignored. Under an open circuit potentialand for positive voltages, SO42– ionsare the dominant species at the interface. Spectra acquired at biasvoltages on each side of the charge neutral point (CNP), also calledthe point of zero charge, showed an asymmetric change with voltagefor H-bonded bulk water molecules and for molecules with danglingOH groups at the interface. These changes are also evident in KPFMmeasurements of the contact potential difference (CPD) between thetip and graphene. Such results are partially consistent with previousobservations.21 The dangling O–H stretchvibrational peak of water is largely unaffected by changes in concentrationand applied bias, except at voltages below −0.3 V, where itshifts to a lower frequency and gets buried into the peaks of H-bondedwater, implying a change of hydrophilicity at a negatively biasedgraphene electrode.Three salts, Na28 To check the effects of contamination, we prepared graphene in threedifferent ways before transferring to the water surface: (1) ultraviolet(UV) irradiation for 5 min, (2) washing in a mixture of acetone andisopropyl alcohol (IPA) (1:3) for 30 min, and (3) as received, i.e.,no treatment (see Section S3). To assessthe amount of hydrocarbon contamination on graphene, we measured theintensity of the C–C and C–H stretch and CH2 twist peaks with Raman spectroscopy, as described in Section S3. With reference to the peaks froma saturation layer of polyethylene formed by immersing graphene ina 1.6 μM polyethylene/CCl4 solution, we found thatthe level of contamination was 0.05 ML after a UV treatment, 0.13ML after IPA washing, and 0.14 ML in the untreated sample. However,the “cleanliness” of graphene after these treatmentswas found to be short lived. As shown in Section S5, after 30–60 min in air in our laboratory conditionsfollowing the cleaning procedure, the sample became contaminated againto their precleaning level. Therefore, all experiments reported herewere performed on samples with a hydrocarbon coverage of about 0.14ML.It has been reported that graphene may suffer from air-borne hydrocarboncontamination.As shown in –1. This change is the result of the symmetry rules governing the sumfrequency generation (SFG) process, which requires a lack of inversionsymmetry. At the interface, there is an intrinsic lack of inversionsymmetry manifested by the intense peak around 3620 cm–1 due to the dangling O–H stretch vibration mode of the watermolecules at the interface next to graphene, which is not affectedby the salt concentration. However, most of the H-bonded water moleculesbelow the first layer are randomly oriented; i.e., they are symmetricas an ensemble within a volume of wavelength dimensions and thereforecannot generate an SFG output. The orientation ordering is not abruptbut decays rapidly from the interface to the bulk interior. As a result,the O–H stretch vibration peaks of the molecules have smallintensities.The differential segregation of cations and anions near the graphene–waterinterface creates an electric field in the double layer with an intensitythat depends on ion concentration. The field affects the vibrationspectrum of the water molecules and changes the intensity of the peaksin the O–H stretch region, between 3000 and 3600 cmWe should note here that the probing depth of SFGis not determined by the penetration depth of the photons, which ismacroscopic for the visible beam and of micrometers for the IR beam,much larger than the Debye length (of an order of 1 nm), or the Gouy-Chapmanlength (angstroms). Instead, it is determined by the depth of theilluminated region lacking inversion symmetry. The presence of electricfields tends to orient the molecular dipoles along the field direction,i.e., perpendicular to the interface, which break the inversion symmetryand cause the intensity increase observed in the SFVS signal seenin S,eff2 (ω), of interfacial water, which depends on the electric field EDC following the expression:29S(2) denotes the contribution from water molecules right atthe interface, while the integral describes the contribution fromfield-induced polarization of water molecules in the diffuse layer. EDC(z) is the distance-dependentfield along the surface normal, χB(3) isthe third order nonlinear susceptibility of bulk water, and Δkz is the phase mismatch in the SFVS process.The change of χS,eff2 (ω) directlyreflects the change of EDC(z) in both magnitude and direction.The intensity of the SFVS peaks is determined bythe effectivesurface nonlinear susceptibility, χ4Cl interface shows onlya small change with the salt concentration 2SO4, respectively, with the 2.9 kJ/mol variance likely being due tothe effect of the different positive ions in the salts.ntration 2b, indic32 Finally, distortions of the solvation shell of anions near graphenemay introduce asymmetries in the vibration modes that could increasethe intensity of the SFVS peaks. Since the peak intensities were usedto calculate the segregation energy, this could conduce to an overestimationof the energy. These are all important questions that point the wayfor further investigation in theory and experiments.Thenature of the driving force responsible for the preferentialsegregation of sulfate anions is not clear at present. Our experimentalmeasurements indicate that it is not of electrostatic origin sincethere is no doping charge on graphene at the OCP, as shown by theRaman results in Figure S7). The results at 10 mM concentration where graphenedoping is negligible reveal that the positive bias (2SO4 and (NH4)2SO4 . The ionic charge near the graphene electrode that orientsthe hydrogen bonded water vs bias deduced from the SFVS measurements,using formulas S1–S6 in the SI,is shown in the left Y-axis in Y-axis,normalized to match the SFVS charge value at the CNP. As can be seen,the ion charge density curves measured from SFVS and from CPD showthe same behavior, with a smaller slope for negative biases (pinkbackground) than for positive biases (green background). Such an asymmetricbehavior was also observed on supported graphene electrode/pure waterinterfaces.36 The nonlinear response ofthe water orientation to different gating potentials and ion speciesindicates again that the Stern–Gouy Chapman model does notdescribe properly the EDL at the microscopic scale37 and that more advanced EDL models that include effectsof solvent dipoles,39 ion solvation structure,40 ion finite size,41 and nonelectrostatic forces between molecular species and electrodesurfaces42 should be used. Since the alignment of thewater dipoles by the electric field is the result of competition betweenthe torque on the water molecules by the field–dipole interactionand the hydrogen bonding network near the interface, the electricfield EDC in The differential segregation of ions to thegraphene electrode is also manifested in the increasing ionic chargenear the graphene calculated from contact potential change measuredby KPFM. For the KPFM measurements, we used a different cell wheregraphene covered a gold-coated 100 nm thick SiNx membraneer holes 4. Graphe2SO4, (NH4)2SO4, and NH4Cl, and their effect in creating a double layerstructure that orients the interfacial water. The first water layerin contact with graphene has a dangling O–H bond that pointsto graphene and remains unchanged both with salt concentration andwith increasing positive potentials but undergoes a chemical interactionwith graphene at negative values that decreases its peak intensityand redshifts its frequency. This indicates that graphene has a hydrophobiccharacter for zero or positive bias, as manifested by the strong danglingO−H bond intensity of the interfacial water molecules, anda hydrophilic character at negative bias, as manifested by the peakfrequency shift and the decrease of its intensity. We showed thata preferential anion accumulation at the interface is driven by segregationfrom the solution bulk, which increased with ion concentration. Wehave shown that the differential segregation at the OCP is not drivenby electrostatic effects nor by formation of specific chemical bonds,which is impeded by the large energy required to desolvate sulfateanions. While the origin of this phenomenon remains unclear, we speculatethat it could be due to reorganization of water in the solvation shellthat breaks the symmetry of the bonded O–H stretch modes. Thistherefore requires further experimental or theoretical study of thestructure of the EDL. We showed also how externally applied fieldsfurther enhance the segregation effects and lead to an increased orientationof interfacial water. The asymmetric change of the field-induced H-bondedwater orientation is proved by both SFVS and KPFM and brings to thefore the need for further studies, particularly theory to better understandit. Finally, we found that the dangling O–H peak of the watermolecules next to graphene remains largely unchanged as a functionof concentration and also under a positive bias but redshifts anddecreases in intensity at a negative bias, pointing to orbital hybridizationbetween dangling H and graphene.In summary, through the combined use of Ramanspectroscopy, SFVS,and KPFM, we determined the effects of the differential ion segregationat the graphene–electrolyte interface in three salt solutions,Na2S2O8 solution leaving suspended graphene with a PMMA/copper frame,floating on the water solution. A potentiostat was connected to graphenethrough the supporting copper frame. To make the sample more robust,two layers of graphene were transferred sequentially, as describedin the SI.We used suspended graphene electrodesmade from CVD-grown grapheneon copper foil (Graphenea Inc). PMMA was first pasted around the edgesof the copper foil on both sides. The copper in the middle regionwas then etched away with a 0.1 M Na43 A Laser Vision opticalparametric generator and amplifier system converts the 1064 nm lightto a visible 532 nm beam and a mid-infrared beam ranging between 2200and 4000 cm–1. SFG is achieved when the visibleand infrared beams overlap spatially and temporally on the sample.The intensity of the sum frequency light as a function of IR frequencyis a vibrational spectrum of the surface species measured in the visibleregion. All the spectra reported in this work were acquired with anSSP polarization combination, where the letters indicate the polarizationof the sum frequency, visible, and IR beams. The CPD was measuredby KPFM with an MFP-3D Asylum Research system, using conductive Pt/Irtips located in the air side of the graphene electrode. The cantileverholding the tip was mechanically oscillated at its 75 kHz resonancefrequency and simultaneous modulated with a 2 kHz AC bias of 3.5 Vamplitude. Tip-sample CPD mapping was obtained in single-pass modewith side-band detection. For Raman spectroscopy, a laser beam withλ = 532 nm was focused on the graphene sample through a longworking distance objective  with a spatialresolution of 0.2 μm. The sample holder used for the Raman experimentsis the same as that in reference (In our SFVS-electrochemicalcell set-up, we used a picosecond lasersystem to generate a 1064 nm near-infrared light with a repetitionrate of 20 Hz.eference .


The energy-dependent angular distribution of the photoelectrons is compared to the simulated electron reflection pattern of a low-energy electron diffraction experiment in the kinetic energy range up to about 55 eV, and the implications for the structure determination are discussed. Constant energy contours due to scattering resonances are well visible in photoelectron diffraction, and their experimental shape is well reproduced. The example of the bilayer graphene is used to reveal the effect of the scattering by the subsurface layer. The photoemission and LEED patterns are shown to contain essentially the same information about the long-range order. The diffraction patterns of C Diffraction of photoelectrons emitted from the core 1 Photoelectron diffraction (PED) ,2,3 has echnique . A conclechnique ,8,9. Recechnique ,11 has aenergies . On the This calls for theoretical methods capable of treating periodic systems with minimum adjustable parameters and providing a straightforward connection to the underlying band structure. The basis for such approaches is the one-step photoemission theory, where the photoemission intensity equals the probability of the transition to the time-reversed LEED state Φk||* ,15,16,17Φk||*  or real-Φk||* . The preΦk||* , where ton Refs. .Nevertheless, the application of the one-step theory is instructive because it uses the same function E and surface parallel wave vector The LEED wave function  in Ref. .z-periodic crystal ∼ of Ref. . Note thAB-stacked bilayer graphene for the normal incidence (Two examples of scattering solutions for the The energy e T(E)=1 ,11,24, ssee Ref. . At the The red-shaded areas in Equation . SomewhaR for the monolayer graphene is compared in s carbon core band and from the 7 eV-wide lowermost valence band (VB)  for thrR and film1-MLRCV.mov provided in the s emission produce very similar patterns, and the VB one is different.The three maps in each row manifest similar gross features, which reflect the structure of the  in Ref.  and firs in Ref. . The pre in Ref. , regardi of Ref. . At E=29The question of interpreting the PED patterns obtained from an extended initial-state band has been first raised in Ref. , where aAB bilayer are presented in t and r, for the incident plane waves with opposite The electron diffraction maps from the rove see  that thene layer . Generalfrom the detector in s states, we can make use of the fact that the coherence of the 1s orbitals at different sites is physically unimportant and consider separately the emission from the front layer and from the back layer, see film3-ABBFT.mov for AB and film4-AABFT.mov for AA stacking). In the example shown in Let us now consider the role of backscattering in the bilayer graphene. One should keep in mind that the time-reversed LEED state is not the true final state of the photoemission process  dAB and AA stacking: Note the rapid growth in reflectivity above 50 eV around the normal incidence for AB stacking, which does not occur for the AA stacking. It is accompanied by an even stronger increase in C AB bilayer that is not seen in the AA one. . The calculations confirm the important role of in-layer scattering in graphene multilayers: many characteristic features are already present in the graphene monolayer. The layer-resolved C The present proof-of-concept calculation demonstrates the prospect of employing the PED technique at low energies in application to 2D crystals and interpreting energy-dependent intensity maps within the one-step photoemission theory. In particular, in the example of graphene monolayer and bilayers, the LEED and PED patterns are shown to contain essentially the same information about the long-range order, the main difference being that for the


A graphene-based transmission line with independent amplitude and phase variation capability is proposed. Variation of graphene’s tunable conductivity by an applied DC bias is exploited in designing an attenuator and a phase shifter. The attenuator and phase shifter are separated from each other by an interdigitated capacitor to ensure independent control of each section through an applied DC bias. The phase shifter is designed by optimizing lengths of a tapered line and an open stub for a maximum variation of input reactance with a change in graphene resistance. The attenuator is designed by two pairs of grounded vias connected to the transmission line through graphene. Variation of graphene resistance controls the signal passing through graphene pads into the ground causing attenuation. An independent variation of 5 dB of attenuation is measured along with an independent phase variation of 23 degrees in the frequency range of 4 GHz to 4.5 GHz. Graphene has been one of the most used innovative materials in recent years ,2. GraphThis variable Fermi energy level causes a variable conductivity, which is very useful for tunable electrical devices . ConventThe synthesis of monolayer graphene requires high technological complexity. Therefore, for the mass scale production of microwave circuitry it is desirable to use multilayered graphene since it exhibits similar tunable conductive behavior at microwave frequencies . It is eSeveral attempts have been made to exploit the variable conductivity for designing tunable microwave components. Attenuators, phase shifters and antennas based on graphene have been proposed in a number of works ,9,10,11.In this paper, for the first time, both the amplitude and phase variations have been introduced on the same transmission line by exploiting graphene’s tunable conductive behavior, unlike only amplitude ,9,10 or The amplitude-phase variation transmission line is composed of a phase shifter, an attenuator and an IDC, as shown in the design of the prototype, shown in The amplitude-phase variation transmission line was designed on an FR4 dielectric substrate that has a dielectric constant, Ɛr = 4.38, and a loss tangent, tanδ = 0.02. The thickness of the dielectric substrate is 1.52 mm. The width of the 50 Ω transmission line is 2.9 mm. The IDC is designed to block the DC bias voltage supplied to each section, permitting the RF signal in the frequency band of 3 GHz to 5 GHz.The IDC is composed of seven identical fingers on each side. The width of the fingers is wd = 0.75 mm and length is Ld = 19 mm. The distance between the fingers is g = 0.25 mm. On the attenuator side, the length of the transmission line is Lat = 30 mm and the distance between the graphene pads is Lc = 5 mm. On the phase shifter side, the length of the transmission line is Lps = 30 mm and the tapered line is Lt = 6 mm. The length of the stub is Ls = 22.5 mm. The stub is 86 Ω, corresponding to a width of 1 mm. The optimized values of the lengths of the stub and taper can be found in [In order to check the functionality of the IDC and the amplitude-phase variation transmission line, the simulations were performed with a commercial FEM tool Ansys HFSS. The simulation results show that the IDC introduces less than 2 dB of the insertion loss in the system, as shown in For the simulations involving the graphene, the graphene pads were modelled as resistive sheets with assigned resistance values in the range of the estimated resistance of the graphene nanoplatelets. The values of Rg and Rg1 are varied, one at a time, keeping the other at the maximum in order to evaluate the individual impact of the attenuator and phase shifter.The maximum and minimum values of the graphene resistance are expected to be 3000 Ω/□ and 800 Ω/□ respectively. It can be clearly seen in The printed circuit board on which the transmission line is present was fabricated with the help of a photolithographic process. The pattern of the transmission line structure is printed with a photoresist on a dual copper-plated dielectric substrate. The unwanted areas lying outside the structure are etched away by ferrous chloride solution. The graphene nanoplatelets used in the transmission line were provided by Alfa Aesar GmbH. The nanoplatelets were characterized by scanning electron microscopy (Tescan Lyra3 FEG) and atomic force microscopy (JPK nanowizard), to investigate their quality and thickness. The measurement setup of the amplitude-phase variation transmission line is shown in The DUT is placed between the two bias tees. The S-parameters are measured for each of the DC bias voltage applied through the bias tees on each side of the transmission line. In this way, the impact of amplitude and phase is individually measured. This causes a large portion of the transmission signal to pass through the graphene into the ground, resulting in attenuation. The maximum variation in |S21| is almost 5 dB, with negligible variation in ∠S21 for the given variation in Rg. For practical applications regarding the antennas and quadrature amplitude modulation schemes, the demonstrated amplitude and phase variation still need improvement. However, this is a proof of concept, and a first step in acquiring a variable amplitude and phase variation on a single transmission line, exploiting graphene’s tunable resistance. A further increase in the number of stubs can provide a higher phase variation. In a similar manner, an increase in the number of vias on the attenuator side can increase the amplitude variation. The unwanted phase variation (in the attenuator) and amplitude variation (in the phase shifter) can be reduced by optimizing the various lengths and widths of the line sections.The benefit of graphene-based amplitude and phase variation is that any number of points can be generated between the extremes by varying the applied DC voltage bias. A small increment is sufficient to vary the graphene resistance, thus varying the amplitude/phase of the signal by a small amount. This could theoretically create infinite number of points on a constellation diagram. In this case of the preliminary modulator, there is no phase shift intended when the attenuation is activated, and no attenuation intended when the phase shifting mode is activated. As shown in Graphene is a scalable material as it retains the same resistance if the aspect ratio is kept the same with a reduced size. This makes it possible to reduce the power consumption as the variation of amplitude and phase is, in principle tied to the resistance. The maximum power requirement of the phase shifter is almost 255 mW and that of the attenuator is 700 mW. This is on the higher side, but if the device is scaled down, this can be reduced while keeping the aspect ratio and resistance constant. The examples of graphene-based devices on a small scale are reported in ,5 where A transmission line based on graphene with the capability of amplitude and phase variation is proposed. The transmission line consists of an attenuator side and a phase shifter side, separated through an interdigitated capacitor. This design ensures independent control of the amplitude and phase. The optimized lengths of lines, stubs and vias in the different sections of the line cause attenuation and phase shift by varying graphene’s resistance through an applied DC bias voltage.


Although polymers are very important and vastly used materials, their physical properties are limited. Therefore, they are reinforced with fillers to relieve diverse restrictions and expand their application areas. The exceptional properties of graphene make it an interesting material with huge potential for application in various industries and devices. The interfacial interaction between graphene and the polymer matrix improved the uniform graphene dispersion in the polymer matrix, enhancing the general nanocomposite performance. Therefore, graphene functionalization is essential to enhance the interfacial interaction, maintain excellent properties, and obstruct graphene agglomeration. Many studies have reported that graphene/polymer nanocomposites have exceptional properties that enable diverse applications. The use of graphene/polymer nanocomposites is expected to increase sustainably and to transform from a basic to an advanced material to offer optimum solutions to industry and consumers. Polymers are important materials in modern society as they are relatively inexpensive and easy to process compared to other materials . However, their inadequate physical properties restrict their application in diverse areas. Therefore, polymers are usually enhanced with fillers of diverse sizes to relieve various restrictions and expand their application areas ,2,3. NanGraphene has proven to be the most powerful material in the world, and has increasingly attracted attention as a promising candidate to substitute the position of carbon-based materials in the enhancement of the mechanical, electrical and thermal properties of polymers. Graphene is a one-atom-thick carbon layer arranged in a honeycomb structure. Additionally, several reports have introduced graphene into polymers for graphene/polymer nanocomposites ,16,17, aSeveral studies have reported a variety of graphene synthesis techniques for pragmatic applications  25]. Ea. Ea25]. Mechanical exfoliation is the simplest process for preparing standalone graphene . In thisCVD is the most beneficial process for fabricating high-quality single-layer graphene for use in various devices . Graphen3, KMnO4, and NaNO3) and concentrated H2SO4, HNO3, or their mixture . Hi. Hi31]. 2 2 2 [2 [2 [[2 [2 [8 , and Sb [2 [2 [8 ), or the8 [2/SO3  and SO3/O3 [3/I2 ). EFGnPs2 adsorption–desorption isotherms [The unique properties of graphene have been verified by diverse analytical techniques. The atomic structure of graphene was verified by transmission electron microscopy (TEM) a, which sotherms . X-ray dsotherms . X-ray psotherms . Raman ssotherms  which casotherms .2/g), intrinsic mobility , tensile strength (130 GPa), Young’s modulus (~1.0 TPa), thermal conductivity (~5000 W/m·K), optical transmittance (~97.7%), and electrical conductivity (~106 S/cm)) have drawn lots of attention [The tremendous attention on graphene has resulted from its exceptional properties, which makes it an attractive material with enormous potential for applications in diverse industries and devices . Its unittention ,53,54,55The intrinsic graphene properties are reduced dramatically as GO includes oxygen-containing functional groups and diverse defects on the basal plane and at the edges, and aggregation, which is derived from the high specific surface area and the strong van der Waals force between graphene sheets ,57,58. P2sp to 3sp, resulting in π-conjugation bond damage.Covalent functionalization introduces new functional groups to enhance the performance of graphene and graphene-like nanomaterials. GO comprises a variety of oxygen-containing functional groups  that can be applied to general chemical reactions  ,61. Addiπ–π interactions, hydrophobic forces, hydrogen bonding, van der Waals forces, ionic bonding, and electrostatic effects [Non-covalent functionalization can be generated through supramolecular chemistry including  effects ,66. The The solution method is the most vastly used technique to prepare polymer nanocomposites on the laboratory scale due to its high utility through the use of diverse solvents and graphene along with a fast and simple process ,68,69. TThe melting method is an industrial-friendly process to predominantly produce thermoplastic-based nanocomposites owing to its rapid and economic process ,70. ThisIn situ polymerization enables the filler to be grafted onto the polymer, which improves the compatibility and interface between the constituents ,72,73,74Electrospinning is used for preparing fine nanofibers with average diameters ranging from nanometers to micrometers ,75. ElecElectrodeposition is a simple and fast method for producing nanocomposites via electrochemical reactions . It invoCarbon-based polymer nanocomposites have been used to improve the mechanical performance of pure polymers by increasing the interaction between polymers and carbon materials. Among them, graphene/polymer nanocomposites exhibit significantly improved mechanical properties compared to those of pure polymers ,78,79. TIn the case of ultrahigh-molecular-weight polyethylene (UHMWPE)/thermally reduced graphene oxide (TrGO), the tensile strength and Young’s modulus improved with an increase in the TrGO content due to the exceptional inherent TrGO strength and stiffness . In the High-density polyethylene (HDPE)/graphene nanocomposites were prepared directly from HDPE and graphene using a twin-screw extruder. HDPE stiffness increased significantly with increasing graphene content, with a maximum Young’s modulus (187% increase) . TherefoHeptene-functionalized graphitic nanoplatelets (HGN) produced by ball milling were incorporated as reinforcing fillers for LLDPE (linear low-density polyethylene) . The tenPolypropylene (PP)/reduced graphene oxide (PP/rGO_X) nanocomposites with low rGO concentrations  were created via twin-screw extrusion . The tenPP/graphene (polypropylene coated graphene) nanocomposites with exfoliated PP-coated graphene, which can prevent the restacking of graphene sheets during melt blending, demonstrated exceptional interaction and effective load transfer between the polymer and graphene . In the Edge-propylene graphitic nanoplatelets (EPGnP/PP)/PP_X nanocomposites were prepared utilizing a solution method . EPGnP/PThe epoxy/GNP_X nanocomposites manufactured by melt mixing demonstrated an increase in the GNP content, tensile strength, and Young’s modulus of the nanocomposite . In epoxDiverse epoxy nanocomposites with pristine- and Triton-graphene  have been prepared [PVA/GO-X (X = GO content) nanocomposites were prepared utilizing the solution method . ComparePVA/GO-X (X = GO content) nanocomposites were prepared via in situ polymerization . The tenPU-GX (X = graphene content) nanocomposites were prepared with waterborne biodegradable PU and graphene at diverse graphene contents  . GraphenPU/graphene nanofibers were obtained by electrospinning a PU/graphene solution comprising GO, f-GO , and r-GO at diverse concentrations  . The modHyperbranched aromatic polyamide-functionalized graphene sheets (GS-HBA) were prepared with 3,5-diaminobenzoic acid (DABA) as a monomer . GS-HBA As the GS-HBA content increased, the stress gradually increased, and the strain steadily decreased. The S–S curve of the 15 wt.% GS-HBA nanocomposite was similar to pure TPU. The highest Young’s modulus of the nanocomposite with 15 wt.% GS-HBA was 1.2 GPa, that is one order of magnitude higher than pure TPU (0.09 GPa). The yield tensile strengths of nanocomposites with 15 wt.% GS-HBA (25 MPa) increased about seven-fold compared with pure TPU (3.4 MPa), that is comparable to UHMWPE (about 22 MPa). Initially, the ultimate tensile strength increased from 18 to 37 MPa, and then decreased slightly to approximately 30 MPa when the GS-HBA content increased to over 2.5 wt.%. GS-HBA may advance strain hardening and strain-induced crystallization of soft segments (SS) owing to hydrogen bonding. As the GS-HBA content increased, the strain at the break of the nanocomposites decreased. PS/FLG-X (X = FLG content) nanocomposites were prepared by combining graphene produced via liquid-phase exfoliation with polystyrene . The YouEdge-styrene graphitic nanoplatelets (StGnPs) were prepared directly using a mechanochemical reaction with graphite and styrene, and StGnP/PS-X (X = StGnP content) nanocomposites were prepared utilizing solution methods . The mecMulti-layer graphene (MLG) PVC nanocomposites  were prepared by in situ polymerization and melt mixing . The yiePVC nanocomposites embedded with graphene nanoplatelets (GNP/PVC) were prepared utilizing a solution method . The GNPGO/nylon 6 was prepared via a solution-mixing method . The incNylon 6/sulfonated graphene nanocomposites  were prepared via in situ ring-opening polymerization of ε-caprolactam and sulfonated graphene (SG) with polar sulfonic acid . Comparem, Tg, Tc of nanocomposites can be found from the measurement data [g, is one of the important factors in polymer treatment and production applications, and it depends on the molecular weight of the polymer chain and the spatial structure of the polymer [The mechanical properties and thermal stability of the graphene/polymer nanocomposite are influenced by the internal microstructure and crystallinity. Thermal properties of polymers can be confirmed with various measuring equipment  and the Tent data . In part polymer .g of pure PVA with the Tg of graphene/PVA nanocomposites. As a result, it can be observed that Tg of the graphene/PVA nanocomposite increased compared to pure PVA. The increase in Tg indicates that the polymer chain was limited by the H-bonding interaction. Load transfer is largely dependent on the interfacial interaction between the filler and the wrapped polymer matrix [c) may also be obtained through DSC measurement. As the content of GNP in the PP/GNP nanocomposites increases, Tc shifted to a higher temperature, indicating that the presence of GNP as a nucleating agent in nanocomposites promotes the crystallization of PP [Differential scanning calorimetry (DSC) is used to study the thermal behavior of the nanocomposites and to follow their melting and crystallization behavior . Liang er matrix . In addion of PP ,146. Theon of PP .The thermal stability and composition of the nanocomposites are investigated using thermogravimetric analysis (TGA). Additionally, TGA was used to confirm filler loading and evaluate the effect of filler loading on the thermal stability in nanocomposites. The degradation performance was improved as filler loading increased, due to the hindered effect of the filler upon the diffusion of oxygen and volatile products throughout the nanocomposite material. That is, it can be seen that the thermal stability of the polymer was improved by adding graphene .g of the composites gradually transfers to higher temperatures [g of the PU nanocomposite by constraining the mobility of PU chains segment [Tensile test and dynamic mechanical analysis (DMA) have been conducted to evaluate the enhancement properties of nanofillers . Accordieratures . The higeratures ,149. The segment .An optimized graphene content in a polymer matrix is typically used for structural reinforcement areas ,152,153.Owing to the outstanding structural strength and conductivity of graphene, polymer nanocomposites have become a potential candidate for aerospace applications . ThermosGraphene/polymer nanocomposites have advantages in diverse environmental applications including water treatment, energy production, and contaminant sensing ,151,155.Research is being conducted on the use of graphene as a new and renewable energy source. In solar cells, graphene either acts as the active medium or as a transparent/distributed electrode material ,156. It Graphene possesses properties that are distinct from those used in biotechnological and bio-based applications. Owing to its large surface area, chemical stability, and functionalization feasibility, it is a promising candidate for tissue engineering, drug delivery, and DNA sequencing . FurtherAmong the various reinforcement materials, graphene has excellent mechanical, thermal, and electrical properties, and is regarded as a better alternative to general nanofillers. Thus, graphene/polymer nanocomposites have properties that are extraordinary for diverse applications. Several studies on the exceptional graphene properties have revealed that it plays an imperative role in enhancing the specific properties of polymer nanocomposites, which can be utilized in diverse applications ,150,158.Current polymer nanocomposites are useful in various aspects. Many studies have been reported demonstrating that graphene/polymer nanocomposites can be applied in various fields through the chemical functionalization of graphene used as fillers. The uniform dispersion of graphene is one of the factors that can improve performance. Additionally, the interaction between the polymer and the filler, the surface area, filler loading, and dispersion are various factors that determine the quality of the nanocomposite. Despite numerous challenges related to graphene, a suitable interaction between graphene and polymers is yet to be developed. However, the manufacturing industry cannot neglect the use of graphene  in commercial products. It is expected that it will be transformed from a typical to a high-performance material that can offer the best solutions for industry and consumers. Therefore, the business influence of graphene/polymer nanocomposites is growing continuously.


In this study, we demonstrate that conducting polymers could be ideal materials for continuously managing humidity in a wide range of enclosed spaces. We demonstrate a simple battery-driven humidity control unit to manage the humidity in a closed environment and studied humidity-responsive nanocapsules using Zn-coordinated lipid nanovesicles. This study not only promises new applications for conducting polymers but also provides an easy approach for fabricating chambers with a controlled environment, which are often used by physicists, chemists, and biologists. In this study, we demonstrate that conducting polymers could be ideal materials for continuously managing humidity in a wide range of enclosed spaces. One method is the gas flow method in which a dry gas that was passed through a desiccant is mixed with a gas that has been passed through water. By controlling the ratio between the two gases, the humidity can be controlled.5 One of the advantages of this method is that an equilibrium can be quickly established , and the changes in the humidity can be continuous. However, this system is relatively complicated and bulky. Aside from the gas supply, a number of different moving parts and valves are required for the construction of the equipment required for this method. Furthermore, the method does not create a closed system, which limits its applicability to laboratory-scale experiments such as gas analysis. The second method predominantly used to precisely control humidity involves the use of saturated salt solutions such as lithium chloride or magnesium chloride.6 This method is highly accurate and relatively simple to perform, because the concentration of a saturated solution is fixed and the vapor pressure can be precisely determined for different temperatures. Because of its high accuracy, this method is used for the certification of humidity sensors. However, this method can lead to salt contaminating a closed system, which is detrimental for laboratory-scale experiments. Furthermore, the humidity value that can be obtained using this method are discontinuous, as the salt solution has to be changed so that different humidity values can be obtained. This can result in it taking several hours for an equilibrium to be achieved.The control of relative humidity (RH) levels in enclosed spaces is not only important for laboratory-scale experiments in physics,In this paper, we report on a simple approach that can be used to precisely control RH levels (from 20% to 90%) in a closed system in a continuous manner; this is achieved through the use of conducting polymer films. This approach involves no moving parts or chemicals that could contaminate an experimental environment, and an equilibrium is achieved within several minutes. By combining a humidity switch module using a printed circuit board, we were able to demonstrate a compact battery-driven humidity control unit that was less than 7 cm × 7 cm in size. We found that this could be used to control the humidity in an environmental chamber with a capacity of over 1 L. We also demonstrated the morphology change of humidity-responsive nanocapsules using Zn-coordinated lipid nanovesicles, which could potentially contribute to the controlled release of chemicals from nanocapsules under different humidity conditions.7 It is well known that PEDOT/PSS films readily absorb water from the air.8,9 The water uptake of PEDOT/PSS films is reported to have a negative effect on the stability and reproducibility of organic electronic devices because many organic semiconductors and metal electrodes are sensitive to moisture.10 However, the extremely strong hygroscopic behavior of PEDOT/PSS films has not attracted much attention. If a freshly prepared free-standing PEDOT/PSS film is placed into a glovebox that has 20% humidity, the weight of the film will increase over time and eventually reach saturation. It has been suggested that this film can absorb water even in very low-humidity conditions and that the hygroscopicity of PEDOT/PSS films could be stronger than that of desiccant silica gels (ca. 0.7 cm3) can absorb roughly 80 mg of water at 20% RH. This value is equivalent to the amount of water contained in 3.4 L of air at 100% RH (the saturated water vapor pressure at 25 °C is roughly 3.2 × 103 Pa). Using the ideal gas law, we find that the volume . In other words, the humidity of a closed system can be controlled using a PEDOT/PSS to gas volume ratio of only 1/5000. This calculation suggests that if one can control the amount of water present in a PEDOT/PSS film, an ideal material for managing the humidity in a closed system could be created.Our proposal utilizes the conducting polymer poly/polystyrene sulfonate (PEDOT/PSS) to control the humidity in a closed system. PEDOT/PSS has attracted a lot of attention owing to its potential for use in applications such as energy storage, energy conversion, and flexible electronics.ica gels . As such11–16 As a benchmark conducting polymer, PEDOT/PSS films exhibit among the highest electrical conductivities  and the electrical conductivity value is less sensitive to the humidity (the amount of water in the film).8 This is because the PEDOT nanocrystals form a layered structure. The spacing between the layers could change before and after the water absorption, but the crystal ordering and crystal size don't significantly affect by the amount of the water in the film  was applied to the film, its weight started to decrease and became saturated at ca. 3 mg. This can be attributed to the desorption of water from the polymer film. A further ca. 10 mg was lost when the current density was increased to 50 A cm−2 (1.0 A), and 18 mg in total was lost for a current density of 75 A cm−2 (1.5 A). Interestingly, the weight lost as a constant current density does not keep decreasing but will saturate at a constant value. Once a larger current was applied to the sample, the weight began to further decrease. However, when the current density decreased, the weight began to increase; this suggests that the PEDOT/PSS film began to absorb water from the environment. The weight of the film did not increase continuously, but rather became saturated at a certain value depending on the current density. At a current flow of zero, the weight of the film reverted to the initial value shown in 17 Note that the carrier mobility in the PEDOT component of the film was partly limited by the columbic interaction of the PSS−. This interaction may have screened the water molecules owing to the high dielectric constant. Once the water was baked out, the carrier mobility decreased, and the resistivity increased. For the same current density passing through the film, the sample temperature was higher during the cooling process owing to a larger resistivity. As a result, the amount of the water uptaken from the air is smaller. At a current density of zero, the temperature of the film should be the same as that of the room temperature, which would result in the weight of the film reverting to its initial value.In order to confirm whether water absorption and desorption occur in PEDOT/PSS films during current flow, we prepared a free-standing film with a thickness of e sample . The exp−2 pulse current at a duration of 60 s to the films. The weight of the films quickly decreased before returning to their initial weight after ca. 10 min. The absolute amount of water desorbed during the pulse current and the recovery time remained almost constant, which suggests that the PEDOT/PSS films are very stable. The water desorption of the PEDOT/PSS films during the current flow was faster than the water absorption from the atmosphere. −2, 5 °C for a current density of 50 A cm−2, and 14 °C for a current density of 75 A cm−2. Although a higher current density can desorb a greater amount of water, it is not preferable for humidity control in a closed system because it could raise the temperature of the system. In order to avoid any unwanted temperature changes from occurring during humidity control, we set the current density to being smaller than 40 A cm−2 in our experiment.In order to study the stability and reproducibility of water desorption and absorption of the PEDOT/PSS films during current flow, we applied a 75 A cmca. 20% was maintained as a starting point. As shown in −2 was applied to the film, the humidity increased and became saturated at ca. 30%. The saturated humidity was ca. 42% at a current density of 20 A cm−2, 62% at a current density of 25 A cm−2, and over 86% at a current density of 40 A cm−2. When the current density decreased from 40 to 20 A cm−2, the saturated humidity dropped to 49% owing to the water absorption of the PEDOT/PSS film. When we stopped applying the voltage to the PEDOT/PSS film, the humidity in the box dropped below 30% after 30 min. The change in temperature in the sealed box over the entirety of the measurement process was less than 5 °C. This result is consistent with the observation of the change in weight of the film shown in A PEDOT/PSS film whose dimensions were 2.6 cm × 5.0 cm × 290 μm was fixed inside a sealed box that had a volume of 0.5 L . The humvia an on/off switch; the switch will turn on the power supply to the PEDOT/PSS film when the humidity falls below a previously defined point , and it will turn it off when the humidity rises above a different previously defined point . We continuously conducted the humidity control experiment using a single set-up ; no gas exchange took place during the process. −2. We were able to use a battery-driven on/off switch on a printed circuit board to fabricate the proof-of-concept humidity controller, as shown in †The compact and simple structure of our device is an advantage. The high conductivity of the PEDOT/PSS film makes the device have low power consumption, such that it could be driven using a battery. The two-probe resistivity of the PEDOT/PSS–Au wire in our set-up was less than 0.3 Ω. A 1.5 V battery can produce a current density as high as 35 A cm18 In this paper, we investigate humidity-responsive nanocapsules in a closed plastic chamber using Zn-coordinated lipid nanovesicles . The encapsulation of functional molecules for daily care products and agricultural chemicals and its release is a currently much researched topic.The humidity control approach proposed in this study could be used in a closed system, which has the advantage that it allows us to study a controlled release of chemicals from nanocapsules, because no chemicals or gases are exchanged when the humidity is varied. The control of the release of chemicals from nanocapsules, which are usually accompanied by a morphological change in the nanocapsules under various stimuli, is important because of their applications to medicine, food, and daily care products. However, research into humidity-responsive nanocapsules is far less reported upon than conventional pH-, light-, and temperature-responsive nanocapsules.vesicles .19,20Figles 19,20. This stles 19,20. This reIn conclusion, we have demonstrated a novel approach to controlling the humidity in a closed system with an RH between 20% and 90%. In comparison to the gas flow method and the approach that uses saturated salt solutions, there are no moving parts in our method nor are there any chemicals that will contaminate the experimental environment; furthermore, equilibrium is very quick to achieve. Owing to the high electrical conductivity of conducting polymers, our humidity control unit consumes very little power. We believe that this will allow for humidity control units that can be powered by batteries to be developed. Our proposed device could also contribute to the study of the controlled release of substances for potential future applications in daily care products or agricultural chemicals. This study not only presents new potential applications for conducting polymers but also provides a new way to make more compact, simple, and low-cost environmental chambers.There are no conflicts to declare.RA-008-C8RA01776J-s001RA-008-C8RA01776J-s002


Then, the graphene-modified coating for building was prepared by using graphene-modified styrofoam emulsion. All the performance indexes of the coating are in line with the industry standards, and it still showed benign EMI shielding effect even when the graphene content was low. It is demonstrated that in situ polymerization technology and the application of graphene in resin coatings modification will promote the development of green coatings.With the aim of developing green coatings, styrene–acrylic emulsion has been widely used in architectural coatings due to its excellent environmental protection and energy conservation. Nevertheless, the lack of water and oxygen resistance of water-based styrofoam coatings has promoted various nanomaterials being studied for modification. To improve the performance of waterborne styrofoam coating, we introduced the graphene nanopowder and expected to enable it with the function of electromagnetic interference (EMI) shielding to reduce the damage of electromagnetic radiation. In this paper, the problem of poor interface compatibility between graphene and polymer resin was successfully addressed by in situ polymerization. In the process of pre-polymerization of styrene–acrylic emulsion monomer, graphene-modified styrene–acrylic emulsion was obtained by introducing graphene aqueous dispersion. The results showed that the styrene–acrylic emulsion with 4 wt% aqueous graphene dispersions exhibited the best dispersion stability, improved water and oxygen resistance, and the conductivity reached 1.89 × 10 In the field of green coatings, waterborne coatings which contain no or only a small amount of organic solvents, have the great advantages of low pollution, being tasteless, and causing little or almost no harm to human health and the environment ,2,3. Thuformance ,15,16. Mformance ,18, so eformance .2 foaming technique [Compared with traditional metal-based EMI shielding materials, the excellent properties of conductive polymer composites include electrical conductivity, chemical and temperature resistance, light weight, high specific surface area and large aspect ratio, which are all conducive to the application of EMI shielding . Among technique . Bontas echnique  modifiedechnique . The graechnique ,26. Therechnique  synthesiechnique ,28, it iThis work uniquely introduced in situ polymerization which provides an ideal strategy to overcome the interfacial incompatibility between graphene and the polymer resins; surfactants were added to improve the dispersion of graphene in water; and it successfully realized an eco-friendly method of preparing graphene-modified styrene–acrylic emulsion in aqueous solution. The results revealed that graphene modification can effectively improve the rheological properties of the styrene–acrylic emulsion along with the excellent EMI shielding effect. Finally, this graphene-modified styrene–acrylic emulsion was successfully applied as a waterborne architectural coating which shows excellent water resistance and low water permeability. The successful modification of graphene also affords the coating with good electromagnetic shielding performance. Each performance index of the graphene-modified styrene–acrylic emulsion-based coating reaches the industry standard (T/CNCIA 01004-2017) for application as waterborne graphene electromagnetic shielding coating for architecture. We expect the strategy will open up a new vista in fabricating graphene-modified styrene–acrylic emulsion and the application of waterborne coatings.3) were all purchased from Chemical Reagent Co., Ltd.  with A.R. grade. Ethylene glycol, Thickening agent HS300, Dispersing agent P-19, Wetting agent X-405, Titanium dioxide, White clay (4000 mesh), CaCO3 (1250 mesh), Hydroxyethyl cellulose (HEC), Coalescing agents, Flatting agent 3020, Antifoaming agents 3016, Thickening agent ASE-60 and Corrosion remover 981 were all provided from Fuzhou Aidite New Material Technology Co., Ltd. . All the above chemicals were used as received without further purification.Graphene , sodium carboxymethyl cellulose , Polyvinyl alcohol and sodium ligninsulfonate (SLS) were purchased from Xiamen Kaina Co., Clariant Chemicals Co., Ltd.  and Aladdin Reagents Co., respectively. Styrene (St), butyl acrylate (BA), methyl methacrylate (MMA), propyl methacrylate (n-PMA), alkoxyphenol ethoxylate , sodium polymethacrylate , ammonium persulfate (APS) and sodium bicarbonate  and sodium carboxymethylcellulose (CMC) as stabilizer through the following process . First, Distilled water (150 g) and OP-10 (26 g) were added to a three-necked flask, and then stirred at high speed until foaming. Four kinds of monomers, St (200 g), MMA (50 g), BA (210 g) and n-PMA (9 g), were mixed and added to the foamed emulsifier solution within 30 min. Then the aqueous graphene dispersion was continuously added at the same speed. The obtained mixture was stirred at high speed for 20 min, and then stirred at low speed for 10 min to obtain a pre-emulsion.3 in 12 g deionized water) were added to above mixture at 70 °C. Then the remaining pre-emulsion and the initiator–buffer mixed solution (1.5 g APS and 1.5 g NaHCO3 in 80 g deionized water) were dripped in within 3 h. Finally, an extra dose of initiator solution (0.6 g APS in 10 g deionized water) was continuously added dropwise at the same rate to produce a sufficient polymerization. Cool down naturally after 2 h of reaction.Deionized water (220 g), OP-10 (4 g) and PMA (15 g) were added to a four-necked flask in sequence and stirred at high speed until foaming. One-third of the pre-emulsion and the initiator–buffer mixed solution  The preparation of graphene-modified styrene–acrylic emulsion architectural coatings requires the preparation of premixed slurry; according to the ratio of premixed slurry shown on the left of (2) According to the ratio on the right of Among the above, thickening agent HS300 and thickening agent ASE-60 are increasing the viscosity of the coating, so it can better adhere to the substrate material. Dispersing agent P-19 is used to disperse the particles which need to be dispersed in waterborne coatings on the surface, so that it has better stability. Wetting agent X-405 is to moisten the substrate. Titanium dioxide, White clay (4000 mesh) and CaCO3 (1250 mesh) are fillers. Hydroxyethyl cellulose (HEC) can act as a binder and thickener. Coalescing agents are to make the coating better film. The purpose of adding flatting agent 3020 is to make the fluidity of the coating better and smoother. In the process of high-speed stirring, samples will be bubbles, so it needs to be anti-foamed by agent 3016 to stir more fully and reduce the production of bubbles after coating film.The graphene-modified styrene–acrylic architectural coating is denoted as G-St/Ac-C. The coating without graphene (St/Ac-C) was also prepared for comparison.−1. Rheological properties of styrene–acrylic emulsion were measured using a rheometer . A 40 mm stainless steel parallel plate was used for the tests and the plate gap was 1 mm. All experiments were carried out at a constant temperature of 25 °C. The Zeta potential of aqueous graphene dispersion was measured using a Malvern Zetaszier Nano-ZS; the instrument measures the particle size by the principle of Dynamic Light Scattering (DLS). Before the test, the sample was diluted with deionized water to a certain multiple before measurement. Surface resistivity was measured by using a four-probe setup . The electromagnetic shielding efficiency for graphene-modified styrene–acrylic architectural coating was measured with a shielding effectiveness tester (DR-S02) using the flange coaxial test device for shielding effectiveness.The X-ray Diffraction (XRD) patterns were performed on a Bruker D8 diffractometer with Cu-Kα radiation (λ = 0.15406 nm) over a range of 10–80°. The field-emission scanning electron microscope  and transmission electron microscopy  were carried out to analyze the morphologies and microstructures of the graphene in the styrene–acrylic emulsion. Confocal Raman microspectrometer (DXR2xi) with an Arion laser at the excitation wavelength of 532 nm was used to collect Raman spectra of the samples. To confirm the amount of carbon in the nanocomposites, thermogravimetric analysis (TGA) was performed  in air atmosphere. Fourier-transform infrared (FTIR) spectra were obtained using a Thermo Fisher Scientific Instruments Nicolet iS10 FTIR spectrometer at room temperature in the wavenumber range of 400–4000 cm−1 are corresponding to the characteristic peaks of G-band and 2D-band of graphene, respectively [G/I2D value reveals the number of graphene layers. Generally, graphene with an IG/I2D about 0.5~1 contains 1–2 layers, while multiple layers when IG/I2D = 1.5~3. G/I2D values of the three sites which indicates the graphene stacks with multiple layers other than bulk graphite. Thus, in the following polymerization process, we chose the well-stabilized aqueous graphene dispersion with PVA/CMC (2.67 wt%:1.33 wt%) to modify the styrene–acrylic emulsion.Thus, with the aid of 3 wt% surfactants including PVA (3 wt%), CMC (3 wt%), SLS (3 wt%), PVA/CMC (1.5 wt%:1.5 wt%), PVA/SLS (1.5 wt%:1.5 wt%) and CMC/SLS (1.5 wt%:1.5 wt%), the stability of the dispersion with 5 wt% graphene is remarkably improved. In contrast, when 5 wt% graphene was dispersed in pure water, it almost completely stratifies within one week. Noticeably different from the other surfactant systems with distinct precipitation after two months, the dispersion with PVA/CMC shows little stratification, indicating excellent stability a. Transmectively ,31,32. Tθ = 26° increases. Compared with the film formed from the pure styrene–acrylic emulsion (Dynamic light scattering (DLS), X-ray diffraction (XRD) and transmission electron microscopy (TEM) were performed to identify the successful modification of graphene. Compared to the pure styrene–acrylic emulsion, DLS results show that with the addition of graphene, the size of the particles in the emulsion increases in line with the increasing of graphene addition a. Furtheemulsion c, the fiemulsion d–h show −1 is assigned to styrene–acrylic emulsions [1580/I1600 reveals the graphene content at the corresponding site. As 1580/I1600 gradually decrease from site 3 to site 1, and there is almost no graphene dispersion at site 1 in the blue area. In −1 which are assigned to the vibration of -CH3, -CH2, C=O, C-O, respectively, and the peaks at 759–1059 cm−1 are characteristic peaks of butyl acrylate, which are consistent with the literature results [Raman mapping was performed to characterize the dispersion state and the relative content of graphene in the emulsion. mulsions . Thus, t results . Thus, tFor coatings, the rheological properties are critical. Thus, the rheological properties of the obtained emulsions with different graphene content were investigated a–d. Figu−2 S/cm, when the addition reaches 4.0 wt%. Then, the conductivity sharply drops to 3.62 × 10−3 S/cm at the addition of 4.4 wt%. In order to figure out the mechanism behind the conductivity change with the graphene addition, the exact graphene content in the graphene-modified styrene–acrylic emulsion was investigated by thermogravimetric analysis (TGA), SEM topography and Raman mapping image. As shown in Compared to the traditional nonconductive styrene–acrylic emulsion, the loading of graphene endows the modified emulsion with good electrical conductivity. 3 is distinctly improved in the G-St/Ac-C, indicating that the addition of graphene may facilitate the crystallization of CaCO3 to form more ordered arrangement. CaCO3, as a main filler, has an important influence on the properties of the architectural coating. The enhanced crystallinity of CaCO3 may also be beneficial to improve water resistance and reduce water permeability. Furthermore, To verify the practical application as a waterborne coating, the graphene-modified styrene–acrylic architectural coating (G-St/Ac-C) was prepared according to the industrial formulation . AmazingIn this study, aqueous graphene dispersion with high stability was readily prepared and the graphene-modified styrene–acrylic emulsion was successfully synthesized by in situ polymerization in aqueous solution through a facile eco-friendly method. The graphene was first dispersed into aqueous solution with the aid of polymeric surfactant stabilizer PVA and CMC. Then the aqueous graphene dispersion was added to the pre-emulsion with monomers and initiator. Through in situ polymerization, the graphene was successfully loaded into the styrene–acrylic emulsion. The optimum graphene addition amount (4.0 wt%) was explored through systematically investigating the rheological properties, conductive properties and the exact graphene content with different graphene additions. The graphene modification improved the rheological properties of the styrene–acrylic emulsion and endowed it with excellent electrical conductivity. The emulsion was further applied as graphene electromagnetic shielding coating for architecture and every performance reaches the industry standard. We hope this in situ polymerization method for graphene-modified styrene–acrylic emulsions will be a potential application in the field of environmentally friendly coatings.


The SEM morphology revealed a sphere-like fluffy structure, particles of the 0.4%rGO-10%SnO2-Fe2O3 composite were smaller and more compact with a specific surface area of 223.19 m2/g, the first discharge capacity of 1423.75 mAh/g, and the specific capacity could be maintained at 687.60 mAh/g even after 100 cycles. It exhibited a good ratio performance and electrochemical reversibility, smaller charge transfer resistance, and contact resistance, which aided in lithium-ion transport. Its superior electrochemical performance was due to the addition of graphene, which made the spherical particle size distribution more uniform, effectively lowering the volume expansion during the process of charging and discharging and improving the electrochemical cycle stability of the anode materials.To enhance the conductivity and volume expansion during the charging and discharging of transition metal oxide anode materials, rGO-SnO These materials also have the advantages of low working potential, simple charging and discharging cycles, and abundant reserves, which makes them potential candidates [The acceleration of social progress and industrialization will create an increasingly high demand for energy resources. At present, the commercial lithium-ion battery anode material is mainly graphite, which has a small theoretical specific capacity 372 mAh/g) and hence cannot meet the power supply demand of large equipment ,2,3. The mAh/g anndidates . Howeverndidates ,13,14,15ndidates ,17,18.2@Fe2O3 double-shell hollow spheres. For a current density of 100 mA/g, the specific discharge capacity decreased to 464 mAh/g after 46 cycles while increased to 1043 mAh/g after 190 cycles, showcasing better electrochemical performance. Chai et al. [2O3 nanostructured anode materials by simple pyrolysis deposition of ferrocene on stainless steel substrates. After 300 cycles at a current density of 500 mA/g, it could still retain a high reversible specific capacity of 1138 mAh/g.Cui et al.  used a ti et al.  used glui et al.  prepared+ embedding and removal, alleviating volume expansion [2O3/graphene nano-sheets by a simple and effective spray drying method, which showed a specific capacity of 711 mAh/g after 50 cycles of charging and discharging, and the chemical properties were quite improved. Qin et al. [2O3/N-doped graphene (Fe2O3/N-rGO) anode materials by a one-step in situ hydrothermal growth method. The porous structure and the introduction of curly GO greatly improved the electrochemical performance of the composite electrode, and the discharge-specific capacity was maintained at 1072.5 mAh/g after 100 cycles. Yang et al. [3O4 nanoparticle coated with graphene (GE-Co3O4) exhibited a high reversible specific capacity of 1100 mAh/g during the first 10 cycles, and the reversible specific capacity could be maintained at 1000 mAh/g even after 130 cycles, showing excellent cycling performance. Therefore, it exhibited great potential as an anode material for lithium storage. Lian et al. [2/graphene composites. The SnO2 nanoparticles could be uniformly distributed on the graphene substrate and showed a reversible specific capacity of 1304 mAh/g at a current density of 100 mA/g. Zhou et al. [+ embedding. Hu et al. [2 nanospheres with GO. This compound exhibited excellent electrochemical performance with a high reversible specific capacity of 1107 mAh/g after 100 cycles at a current density of 0.1 A/g.Due to the unique structure of graphene, it can show good electrochemical performance when used as the anode material of lithium-ion batteries ,24,25,26xpansion ,33,34,35xpansion  preparedn et al.  preparedg et al.  introducn et al.  developeu et al.  synthesiu et al. ,42,43,44u et al.  combinedu et al.  synthesi2-Fe2O3 composite materials. The phase composition and microstructure were determined by XRD and SEM. The charge and discharge performance, cycle performance, rate performance, and AC impedance of the materials were tested. The physical and chemical properties and internal mechanisms of the composite materials were explored.To enhance the conductivity and volume expansion in the charging and discharging cycles of transition metal oxide anode materials, this paper employed the in situ hydrothermal synthesis method to prepare rGO-SnO2-Fe2O3 composite metal oxide. The Sn content was calculated as SnO2, the mass percentage was fixed at 10%, and the graphene content was varied as 0.2%, 0.4%, 0.6%, and 0.8%, respectively.A certain amount of graphene oxide was added to deionized water and ultrasonic dispersion for 1 h, then the percentage of tin chloride and ferric chloride was dissolved. Then, sodium hydroxide solution (1 mol/L) was added during the mixing process until the solution pH reached approximately 9. After stirring for 4 h, the mixture was shifted to the high-pressure reaction kettle  for 4 h under 100 °C. It was further cooled to room temperature and allowed to stand for 8 h, washed, dried at 60 °C for 24 h, and lastly, vacuum roasted at 400 °C for 4 h to obtain the rGO-SnOThe prepared anode material was used as the active material, acetylene black was used as the conductive agent, and PVDF was used as the binder. The mass ratio was fixed as 8:1:1. N-methyl pyrrolidone (NMP) was used as the solvent to prepare the slurry. After coating, vacuum drying at 80 °C for 12 h, and stamping, the electrode sheet was ready for use.6/ethylene carbonate (EC) + dimethyl carbonate (DMC) (volume ratio was 1:1) mixture solution was used as the electrolyte. The battery was assembled according to a certain sequence of a positive shell, electrode sheet, diaphragm, lithium sheet, gasket, spring sheet, and negative shell. During the assembly process, the electrolyte was added to both sides of the diaphragm.The electrochemical performance tests of electrode materials were executed by using the half-cell test system, the prepared electrode sheet as the anode, the lithium sheet as the counter electrode and auxiliary electrode, the polypropylene microporous membrane  as the diaphragm, and 1 mol/L LiPFThe surface morphology of the anode material was observed and analyzed by a SSX-550 tungsten filament analytical scanning electron microscope .A X ‘Pert Pro MPD diffractometer PW3040/60 manufactured by Koninklijke Philips N.V., Amsterdam, The Netherlands was used. The Kα of the Cu target was the radiation source (wavelength 1.540598 A), the working voltage was 40 kV, the sweep speed was set as 6°/min, and the sweep range was 10–90°.The surface area tester (Micromeritics ASAP 2020) produced by Micromeritics  was used to calculate the specific surface area of the sample by Brunauer–Emmett–Teller (BET) isotherm method.A constant current charge/discharge test was carried out following the steps of static-constant current discharge-static-constant current charge-constant voltage charge. The test voltage window was set as 0.01–3 V. The charge and discharge current values were calculated from the theoretical specific capacity and the mass of the active substance.The instrument used for the cyclic voltammetry test was the CHI660D electrochemical workstation of Shanghai Chenhua Company, Shanghai, China. The test conditions were as follows: scan rate of 0.1 mV/s, the voltage scan range of 0–3.0 V.In the Electrochemical impedance spectroscopy test, the frequency range was 0.01 Hz–1 MHz, and the voltage vibration amplitude was 5 mV.2-Fe2O3 composite oxide samples with varying graphene contents, and the corresponding specific surface area is listed in 2-Fe2O3 composite oxide exhibited an irregular structure. After adding graphene, the rGO-10%SnO2-Fe2O3 composite materials exhibited a globular fluffy structure, and the granular complex was distributed on the surface of the gossamer graphene, in between the lamellae  [4+ to Sn2+ disappeared. The oxidation peaks of the first cycle appeared at 1.7 V and 2.0 V, corresponding to the transformation of Fe0 to Fe3+ and Sn2+ to Sn4+. The cyclic voltammetry curves overlapped well, suggesting higher reversibility and better stability.Cyclic voltametric curves of 10%SnOnversion ,50,51. IEI film) ,53, and 2-Fe2O3 composites with different graphene contents are shown in 2-Fe2O3, 0.6%rGO-10%SnO2-Fe2O3, 0.8%rGO-10%SnO2-Fe2O3, 0.2%rGO-10%SnO2-Fe2O3 and 10%SnO2-Fe2O3. After graphene addition, the resistance of the material decreased, which was closely related to the effect of graphene on the microstructure. Among them, when the graphene content was 0.4%, the 0.4%rGO-10%SnO2-Fe2O3 anode material possessed the smallest semi-circuit radius, indicating that it had the smallest contact resistance and charge transfer resistance, which was conducive to the transport of lithium ions and was consistent with the cycling performance results. With the amount of graphene increasing, as in 0.8%rGO-10%SnO2-Fe2O3, the charge transfer resistance was increased due to the agglomeration phenomenon and lower specific surface area.The AC impedance spectra of rGO-SnO2-Fe2O3 anode materials were prepared by using SnO2-Fe2O3 as the matrix and adding graphene oxide in varying contents. The structural characterization and electrochemical performance of the above materials were investigated, and the following conclusions were drawn: (1) The phase structure of the rGO-SnO2-Fe2O3 composite was SnO2, and the morphology was a globular fluffy structure. The granular complex was distributed on the surface and between the lamellae of the bubble graphene. The morphology of 0.4%rGO-10%SnO2-Fe2O3 composite was the best, and the spherical particles were smaller and more in numbers. The spherical particles were more closely packed, and the specific surface area was 223.19 m2/g. (2) The cycle performance of the 0.4%rGO-10%SnO2-Fe2O3 anode material was the best, the first discharge-specific capacity was 1423.75 mAh/g, and after 100 cycles, the capacity was maintained at approximately 687.60 mAh/g. The results of different rate tests showed that the specific capacity of the 0.4%rGO-10%SnO2-Fe2O3 anode material decreased with an increase in the rate, but the overall rate of decline was relatively slow. (3) 0.4%rGO-10%SnO2-Fe2O3 exhibited better electrochemical reversibility, smaller contact resistance, and charge transfer resistance. All these characteristics were beneficial to the transport of lithium ions and were consistent with the cycling performance results. (4) The excellent electrochemical performance of 0.4%rGO-10%SnO2-Fe2O3 can be attributed to the addition of graphene, which made the size distribution of spherical particles more uniform, effectively alleviating the volume expansion phenomenon during the process of charging and discharging. This has further enhanced the electrochemical cycle stability of anode materials. It can be seen from the experimental results that the addition of graphene can improve the specific capacity and cycle stability. However, it has no significant effect on the capacity attenuation in the first lap, which will be paid more attention in the later research.In this paper, rGO-SnO


Recently, it was associated with higher rates of progression to chronic osteomyelitis in pediatric patients with acute MSSA osteomyelitis, independent of the treatment choice. Thus, its detection could be important for management of certain MSSA infections. Broth microdilution at high inoculum is the gold standard for the detection of the CzIE. Yet, this method is lengthy (3–5 days), cumbersome, and expensive. We developed a nitrocefin-based rapid test (∼3h) which can identify the CzIE among MSSA isolates and that can be incorporated in the laboratory workflow. Previously, this rapid test was validated in MSSA isolates from adult patients with bacteremia. Here, we aimed to validate it in isolates from pediatric patients with acute MSSA osteomyelitisThe cefazolin (Cz) inoculum effect (CzIE) defined as a Cz MIC ≥ 16 µg/mL at high inoculum . Performance metrics were calculated for the complete data set and for specific BlaZ types.We included 206 MSSA isolates from the same number pediatric patients from Houston, TX (2011–2018). All patients were diagnosed with acute MSSA osteomyelitis. The CzIE was determined using broth microdilution at high inoculum with a cutoff of Cz MIC ≥ 16 µg/mL. Whole genome sequence analysis was performed using Illumina Hi-Seq. BlaZ type was determined according to predicted BlaZ residues at position 119 and 207. The nitrocefin rapid test was performed following the published protocol . The false negative and false positive rate of 9.2% and 13.8%, respectively, with an overall accuracy of 89%. There were no false positive results among blaZ negative strains. Among type A BlaZ MSSA, the sensitivity was 96.7%, and the specificity was 80%, while in type C BlaZ, they were 70.5% and 92.8%, respectively.The prevalence of the CzIE was 33%. Compared to the gold standard, the nitrocefin rapid test had a Performance metrics of the Nitrocefin-based Rapid Test in 206 MSSA isolates from pediatric patients with acute MSSA osteomyelitis compared to the Gold Standard of Broth Microdilution at high Inoculum.The nitrocefin-based rapid test was able to correctly detect the CzIE in isolates from pediatric patients with MSSA acute osteomyelitis, with an overall accuracy of 89%. Implementation of this test may contribute to therapeutic decisions in deep-seated MSSA infections.Sheldon L. Kaplan, MD, MeMed: Grant/Research Support|Pfizer: Grant/Research Support Jonathon C. McNeil, MD, Agency for Healthcare Research and Quality: Grant/Research Support|Allergan: Provided reagents for unrelated research|Nabriva: Site investigator for multicenter clinical trial Cesar A. Arias, MD, PhD, Entasis: Grant/Research Support|MeMed Diagnostics Ltd: Grant/Research Support|Merck: Grant/Research Support.