New cyclotriphosphazene (CP) derivatives bearing two or six triethoxysilyl groups were synthesized via aminolysis of N 3 P 3 Cl 6 . With a view to decreasing the steric hindrance in the consequent sol-gel process, silane groups in a non-geminal position were introduced in the phosphazene ring in a two-step reaction. In the rst stage, non-geminal tetrasubstitution with morpholine or dimethylamine was performed. In the second stage, the preserved non-geminal chlorine atoms were replaced by 3-aminopropyl-triethoxysilyl groups. The structures of the products were con rmed by IR, 1 H-NMR, 13 C-NMR, and 31 P-NMR spectroscopy. The reactivity of the triethoxysilyl-containing CPs in the formation of a SiO 2 network was proved in the presence or in the absence of tetraethoxysilane (TEOS). By adding a water-soluble polymer -poly(vinyl alcohol) -as a third component, organic-inorganic composites were prepared and characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA).
Abstract:The influence of the macromolecular architecture of block copolymers containing poly(N,N-dimethyl acrylamide) (PDMA) on the optical characteristics and sensing properties of corresponding thin films is discussed. Series of hydrophilic PDMA-based copolymers of different chemical composition and chain architecture such as triblock, star-shaped, and branched were synthesized. The copolymers were characterized using conventional spectroscopic techniques as well as methods for characterization of copolymer macromolecular characteristics in solution, namely size-exclusion chromatography and static light scattering. Thin films of the copolymers of nanometer scale thickness were deposited on silicon substrates by the spin-coating method. The refractive index and extinction coefficient of the copolymer films were calculated from the reflectance spectra by using non-linear curve fitting methods and the composition-structure-optical properties relationships were evaluated. Humidity-sensing properties of the films were studied by measuring reflectance spectra of the films at a relative humidity range from 5 to 95%RH. The implementation of the copolymer films as optical sensors of humidity is justified and discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.