Fabrication and structure-directing mechanism of oriented TS-1 films
The b-oriented TS-1 films on α-Al2O3 substrates were synthesized by using in situ crystallization by the inducing effect of the chitosan thin film.The synthesized TS-1 films were characterized with XRD and SEM.The functional groups on the chitosan film surface and the interactions between the chitosan film and synthesis solution were described by using diffuse-reflectance FT-IR and contact angle measurements.It was shown that the b-oriented TS-1 film could be synthesized with the help of the chitosan thin film,whereas the randomly oriented TS-1 film was obtained on the α-Al2O3 substrate without chitosan induction.The XRD patterns of the synthesized films revealed that the crystals possessed TS-1 zeolite structure.The diffuse-reflectance FT-IR spectrum and contact angle measurements exhibited that the functional groups were abundant on the surface of the chitosan thin film,which could attract organic and inorganic compounds.Therefore,a transitional layer could be formed on the chitosan film,with nucleation and crystal growth to sheet-shaped TS-1 crystal grains,eventually leading to the formation of the multilayer b-oriented TS-1 film.