Thermoresponsive cryogels of poly(2-hydroxyethyl methacrylate-co-N-isopropyl acrylamide) (P(HEMA-co-NIPAM)): fabrication, characterization and water sorption study

Abstract

Cryogels of poly(2-hydroxyethyl methacrylate-co-N-isopropylacrylamide) (P(HEMA-co-NIPAM)) were prepared by cryogelation technique. Redox polymerization method was utilized to copolymerize monomers 2-hydroxyethyl methacrylate (HEMA) and N-isopropylacrylamide (NIPAM), using N, N′-methylene-bis-acrylamide (MBA) as cross-linker. Characterization of the as-prepared cryogels was done by Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis and X-ray diffraction techniques, respectively. During synthesis of cryogels, the concentrations of HEMA, NIPAM, MBA, redox initiator, and activator and the number of freezing–thawing cycles were varied to obtain different compositions of P(HEMA-co-NIPAM) cryogels. These cryogels were further evaluated for water sorption capacity through gravimetric method. The pH, temperature and nature of the swelling medium were also varied to observe their effects on water uptake capacity of the cryogels. The biocompatible nature of the materials was ascertained by blood hemolysis test. The prepared cryogels of P(HEMA-co-NIPAM) were found to be macroporous, have good water uptake potential, fair biocompatible, thermally stable nature, displayed temperature-sensitive water sorption behavior and thus showed potential to be utilized as scaffold in tissue engineering.