Fabrication and Properties of Thermosensitive Organic/Inorganic Hybrid Hydrogel Thin Films

We report on a facile method for fabricating thermosensitive organic/inorganic hybrid hydrogel thin films from a cross-linkable organic/inorganic hydrid copolymer, poly[N-isopropylacrylamide-co-3-(trimethoxysilyl)propylmethacrylate] [P(NIPAm-co-TMSPMA)]. Fourier transform infrared (FT-IR) spectra confirmed the formation of hybrid hydrogel thin films after hydrolysis of the methoxysilyl groups (Si−O−CH3) and subsequent condensation of the silanol groups (Si−OH). Atomic force microscopy (AFM) images revealed that the surface morphology of the hydrogel thin films depended on the supporting substrates. Microdomains were observed for the hydrogel thin films on a gold surface, which can be attributed to inhomogeneous network structures. The thermoresponsive swelling−deswelling behavior and the viscoelastic properties of the hydrogel thin films were investigated as a function of temperature (25–45 °C) by using a quartz crystal microbalance (QCM) operated in water. The high frequency shear modulus of the P(NIPAm-...