Synthesis and Characterization of Poly(N-isopropylacrylamide)/SBA-15 Silica Nanocomposites

The combination of the mesoporous silica material SBA-1 5 with the temperature-responsive hydrogels, such as poly(N-isopropylacrylamide) P(N-iPAAm) can lead to the formation of a material with the potential for application as a new drug delivery system, given that self-regulated delivery allows for drug release when needed. The present work studies the synthesis and characterization of hybrid systems consisting of the poly(N-isopropylacrylamide) hydrogel and SBA-15 by varying the amount of hydrogel within the silica network. A systematic study on the structural properties of hybrid samples, their thermal stability and the degradation of the polymer chains in silica was carried out through characterization techniques, including SAXS, thermogravimetry and physical adsorption of N2. The results were critically examined and compared with pure SBA-15. The present study's results demonstrated that the thermosensibility of P(N-iPAAm) was retained in the hybrid system, which presented a low critical solution temperature, similar to that of pure P(N-iPAAm). Moreover, the hydrogel did not fully occupy the available intrachannel space, making the [SBA-15/P(N-iPAAm)] hybrids a very promising candidate for hosting and further delivery, under appropriate conditions, of a variety of molecules of pharmaceutical interest.