(265h) Synthesis and Characterization of Thermally Responsive N-Isopropylacrylamide Hydrogels Copolymerized with Novel Hydrophobic Polyphenolic Crosslinkers
Thermosensitive hydrogels were synthesized by copolymerizing N-isopropylacrylamide (NIPAAm) with novel hydrophobic crosslinkers, including curcumin multiacrylate (CMA), quercetin multiacrylate (QMA), and 4,4'-dihydroxybiphenyl multiacrylate (44BMA). Gels were synthesized through free radical polymerization. The crosslinking process was investigated under differential scanning calorimetry (DSC) to obtain the optimized reaction conditions. Hydrogel compositions were then characterized using solid state-NMR (ss-NMR), and the temperature dependent swelling behavior and lower critical solution temperature (LCST) were characterized using swelling studies and differential scanning calorimetry (DSC). Increasing the crosslinker content resulted in a significant decrease in the LCST and swelling ratio of hydrogels, which could be attributed to the increased hydrophobicity introduced by crosslinkers. All of the hydrogels have demonstrated temperature responsive swelling with the extent of swelling decreasing with increasing crosslinker content. The lower crosslinker content gels displayed sharper phase transitions, while the high crosslinker content gels had broader phase transitions.