Evaluation of novel synthetic conditioning polymers for shampoos.
Cationic polymers have traditionally been used in shampoo formulations to impart conditioning properties to hair. In this study, commercial synthetic cationic polymers were investigated using coacervate formation, objective wet comb analysis, silicone deposition and panel studies to determine structure function properties with the goal of developing novel conditioning polymers. New polymers were synthesized and, based on criteria determined in the first part of the study, found to have marginal improvement over existing synthetic cationic conditioning polymers. A novel experimental polymer developed for a different industry was also investigated for conditioning properties. This polymer showed significant enhancement of silicone deposition over current commercial polymers, including cationic guar, even at significantly reduced silicone and polymer concentrations. The experimental polymer exhibited parity or improvement over benchmark polymers in panel studies, and similar performance to other synthetic polymers in objective wet comb studies.
New high-charge density hydrophobically modified cationic HEC polymers for improved co-deposition of benefit agents and serious conditioning for problem hair.
A series of new high charge density Polyquaternium-67(1) (PQ-67) polymers have been prepared and evaluated in shampoo formulations. These new compositions represent an addition to the family of high-viscosity quaternized hydroxyethylcellulose (HEC) polymers with cationic substitution of trimethyl ammonium and dimethyldodecyl ammonium(2) (Figure 1A) described in (1) and (2). The evaluation protocol included objective lab methods and subjective panel studies on different hair types. Commercial conditioning polymers: PQ-67 (Polymers SoftCAT(3)) and cationic guar(4) (Jaguar C-13S(R)(5)) were used as performance benchmarks. It was found that increasing the cationic charge density of the PQ-67 polymers above 1.45 meq/g (equivalent of 2 weight-percent (wt.%) nitrogen) resulted in a several-fold boost of their co-deposition ability. These experimental, high charge density PQ-67 polymers were shown to deliver silicones and other performance ingredients from shampoo formulations more efficiently than any other polymer currently available on the market for rinse-off hair cleansing/conditioning applications. The polymers also provided improved wet and/or dry conditioning, volume control, and could be instrumental in achieving sleek looking hair and improved control/manageability of unruly or frizzy hair. The high charge density PQ-67 polymers are also ideally suited for highly-fragranced surfactant-based formulas that are used in aromatherapy and spa products due to their superior ability to deliver fragrance.
Photoreflectance characterization of vanadium-doped GaAs layers grown by metalorganic vapor phase epitaxy
Abstract We characterized the vanadium-doped (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy. The conductivity of the samples is checked by the Hall effect measurements, and it is n type with electrons concentration ranging from 2×10 13 to 2×10 17  cm −3 . We used the photoreflectance technique (PR) to study the effect of vanadium doping on the optical properties of GaAs. Our experimental results show that the built-in electric field F and the broadening parameter Γ 0 increase with V-doping concentration. Furthermore, the temperature dependence of the built-in electric field and the broadening parameter of GaAs:V samples have been investigated by PR. It has been observed that these parameters increase with increasing temperature. The decrease of the built-in electric field with decreasing temperature is due to the photovoltage effect.We characterized the vanadium-doped GaAs (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy.