How does pH affect hydrogel?

Answer 1

pH has a vital role in formation of coacervates. pH changes the surface charge of the polymer in its solution. When two types of charges are present in the solution, the environment prefers binding and crosslinking. When this sort of aggregation develops, we see droplets of coacervates in the system. now How pH changes the surface charge density? The total charge of the polymer solution(system) is zero at its pI or isoelectric point which is fixed for a particular polyampholytic polymer like Gelatin. However no pI exists for purely anionic and purely cationic polymers. For example, Agar is a polyanionic polymer. When the pH of solution is less than the PI, the positive charges get dominated over it and vice versa. These charges affect the binding property in the system and hence the coacervate formation. Answered by Shilpi Boral.