Used as a reactive polymer in coatings and adhesives due to its ability to form complexes with metals and cross-linking agents. Employed in gas separation membranes for its selective permeability to certain gases like carbon dioxide. Serves as a precursor in the synthesis of functional materials, including catalysts and ion-exchange resins. Applied in biomedical fields for drug delivery systems because it can respond to pH changes. Also utilized in electronics as a component in sensors and conductive films when doped with appropriate agents. Additionally, it acts as a catalyst support in organic synthesis reactions, such as nucleophilic substitutions and hydrogenations, facilitating easy separation and reuse of metal catalysts like palladium or platinum.