pH-RESPONSIVE GEL, PROCESS FOR PRODUCING THE SAME, AND pH-RESPONSIVE VALVE

摘要

A pH-responsive gel which comprises a polymer, characterized in that when the weight of the pH-responsive gel in a solution having a pH of X (X is a number of 7 or smaller) is expressed by WX and the weight of the pH-responsive gel in a solution having a pH of Y (Y is a number of 7 or smaller, provided that YX and the difference between Y and X, i.e., Y-X, is 3 or smaller) is expressed by WY, then WY is from 0.2WX to 0.9WX. Also provided is a pH-responsive valve having a passage opening/closing member comprising a polymer hydrogel which reversibly shrinks and swells with pH. The liquid passage from the upstream side to the downstream side of the valve is opened by the pH-dependent shrinkage of the passage opening/closing member and is closed by the pH-dependent swelling of the passage opening/closing member.