Thermoreversible hydrogels. XII. Effect of the polymerization conditions on the swelling behavior of the N-isopropylacrylamide gel

The swelling behavior for the poly(N-isopropylacrylamide) (NIPAAm) hydrogel prepared in various conditions such as various polymerization media, i.e., deionized water, acetone, and ethanol aqueous solution, and different poly merization temperatures were investigated in this work. The gels were also assessed for suitability in drug-controlled release. The results indicated that the swelling behavior of the gel was dependent on the polymerization m edia and temperature, that is, the swelling ratios of gel were related to t he pore size and the looser or denser structure of the gel. In addition, th e pore size of the gel could be controlled by adjusting the surrounding tem perature. Hence, the gel can be used to deliver drugs with different sizes. (C) 2000 John Wiley & Sons, Inc.