Preparation of a Polyelectrolyte Complex Gel and its pH-Dependent Swelling Behavior

Abstract

A Polyelectrolyte complex gel was made by mixing chitosan and xanthan solutions under the presence of NaCl. To study the effect of environmental pH on the swelling behavior, the gel in cylindrical shape was immersed in aqueous NaOH or HCI solution, and the diameter of the gel was measured at appropriate intervals. In the range of pH 10-12, the diameter increased with time, and the gel reached to the swelling equilibrium not more than 7 days. The gel also swelled at pH below 1.5, though it dissolved in the range of pH 0.2-1. No swelling was observed at pH from 2 to 9. The effect of salt concentration on the pH-dependent swelling of the gel was also investigated.