Random pH-responsive copolymers, P(A/AaU) have been prepared from a pH-responsive pendant fatty acid-containing monomer (AaU) and a pendant sulfonate-containing monomer (AMPS). In water, P(A/AaU) formed unimer micelles under acidic conditions. Under basic conditions, the P(A/AaU) polymer chains expand due to the electrostatic repulsions. Although pH-responsive sunscreen shows waterproof properties under neutral conditions, it disperses under weakly basic conditions such as soap water. pH-responsive diblock copolymers with a pendant fatty acid-containing block were prepared. This review also discusses pH-responsive gelling agents based on ABA triblock copolymers.
