Schiff's base as a stimuli-responsive linker in polymer chemistry

Schiff-base reactions are widely used in the field of chemistry. With many advantages, such as mild reaction conditions and high reaction rates, they were employed for protecting various functional groups and synthesizing a series of organic ligands. In polymer chemistry, they can serve as potential pH-responsive linkers in polymer chains because of their sensitive responses to changes in the pH value. With certain particular designs, the Schiff-base structure can cooperate with other reversible covalent bonds or supra-molecular interactions to form assemblies or gels, providing various functions and applications. This article aims to give a critical review of the recent literature on the Schiff-base reactions used in polymer chemistry and how they serve as a way of linking structures together. We will also cover some of the important developments on the functions and applications of these polymers.