Study on the Swelling and Deswelling of the PH / Thermosensitive Hydrogel

Abstract

From the point of view of molecule design, pH/temperature responsive hydrogels were prepared based on the acrylic acid with the excellent pH sensitivity and N-isopropylacrylamide (NIPA) with the excellent temperature sensitivity by the traditional radical polymerization. Study focus on the swelling of the hydrogels, measurement of the swelling and deswelling under different ionic strength with various temperatures of the hydrogels were performed in our work. The results show that the ionic strength, the pH value and temperature are three key factors that affect the LCST of the hydrogel. In the same pH buffer solution, the swelling ratio decreases with temperature rises, and the ionic strength greatly affects the swelling of the pH temperature responsive hydrogel, the higher the ion concentration is, the lower the swelling ratio and the LCST are.