Smart pH/temperature Sensitive Hydrogels with Tailored Transition Temperature

Dual pH- and temperature-sensitive hydrogels have been prepared based on N-isopropylacrylamide (NIPAAm) and either po- tassium 5-methacryloyloxy-pentanoate (M4K) or potassium11-meth- acryloyloxy-undecanoate (M10K) as comonomers. The gels contain- ing M10K (longer methylene chain) showed a slightly lower swelling capacity than the gels containing M4K. Hydrogels were produced with specific phase transition temperature (Tcr) in the range from 12 to 76 o C for NIPAAm-C4 hydrogels (containing M4K) and from 16 to 36 o C for NIPAAm-C10 hydrogels (containing M10K) by control-