Thermo- and photo-responsive polymeric systems

Since the first reported thermal phase transition of poly(N-isopropylacrylamide) by Heskin in 1968, this unique polymer has continued to gain popularity. Because of their potential applications in the field of biomedical science, various responsive polymeric systems, such as those induced by pH, salt, co-solvent, thermal, light, electric and magnetic field, have been synthesized and studied. This review reports on recent developments (over the last 10 years) of thermo- and photo-responsive homopolymers, copolymers, microgels, hydrogels and polymer brushes at interfaces, where the synthesis, physicochemical properties, and potential applications are highlighted. Although homopolymers and microgels undergo phase transitions upon the application of external stimuli, block copolymers, however, self-assemble into different nanostructures. Such reversible phase transitions and self-assembly behaviors have generated many robust structures that can be applied in coating industries, personal/home care, petroleum, drug/protein/DNA delivery and separation processes.Sheng Dai, Palaniswamy Ravi and Kam Chiu Ta