The preparation and properties of hybridized hydrogels based on cubic thiol-functionalized silsesquioxane covalently linked with poly(N-isopropylacrylamide)

Firstly, nano-sized polyhedral oligomeric silsesquioxane with functional mercapto groups (POSS-SH) was prepared through hydrolytic condensation of 3-mercaptopropyl trimethoxysilane. Then N-isopropylacrylamide (NIPAm) was allowed to polymerize at the presence of POSS-SH and N,N-methylene-bisacrylamide to yield hybridized hydrogels. The hybridized hydrogels demonstrated thermosensitive behavior across the volume phase transition temperatures. The swelling and deswelling rates were greatly accelerated through the incorporating of POSS-SH into the gels, and the thermal properties of the hybridized hydrogels were reinforced compared with the neat PNIPAm hydrogel. These results were ascribed to nano-effect created by the hydrophobic POSS-SH nanoparticles. The hybridized hydrogels have potential applications in drug controlled release.