Structure and characteristics of organic-inorganic hybrid hydrogels based on poly(N-vinylcaprolactam)-SiO2

In the reaction system of poly(N-vinylcaprolactam)-water-tetramethoxysilane, the effect of concentrations and ratios between compounds on the structure and characteristics of the formed organicinorganic hybrid hydrogels based on poly(N-vinylcaprolactam) and silica particles is studied. When the over-all concentration of precursors is increased, the number of bonds between hydrogel components increases, and an increase in the number of network crosslinks is provided by an increased fraction of tetramethoxysilane. The method of small-angle X-ray analysis is used to estimate quantitative structural characteristics of silica particles in hydrogels. Silica particles are found to form a fractal three-dimensional structure, which is composed of individual compact clusters with lateral dimensions of 40–60 Å. The average linear dimensions of scattering anisometric particles are 100 × 120 × 360 three-dimensional structure is proposed for hydrogel formed via the interaction of poly(N-vinylcaprolactam) macromolecules and silica nano-particles. The average distance between silica particles is estimated.