Arun Mondal, Soumya Kolay, Dhiman Mondal, Aditi Banerjee, Mijanur Rahaman Molla
Dynamic covalent poly(disulfide)s are regarded as sustainable intelligent materials for the future because of their dynamicity and recyclability. Consequently, establishing a comprehensive process for the synthesis of poly(disulfide)s with varied structures and functionalities is highly valuable. This work describes a versatile and efficient cascade ring-opening polymerization (ROP) methodology and postpolymerization route for the synthesis of a library of functional poly(disulfide)s with structural diversity. Here, an amine activates a dormant thiolactone ring to produce a thiolate anion initiator, which subsequently opens the pentafluorophenyl ester (PFP-ester)-containing cyclic disulfide (1,2-dithiolane ring) monomer, thereby propagating polymerization at room temperature under open-air conditions. This cascade ring-opening approach facilitates one-step, in situ dual modification at the polymer chain end, thereby enabling pendant modification with both alcohols and amines through organocatalyzed transesterification and amidation, respectively, at room temperature. As a result, the polymerization approach combined with postpolymerization pendant modification allows multifunctionalization at the same polymer chain of poly(disulfide)s. The room-temperature and open-air mild reaction conditions for the polymerization and postpolymerization modification (PPM) protected the integrity of the delicate disulfide bonds. Previously, postpolymerization was largely unexplored for synthesizing a series of pendant ester and amide-functionalized poly(disulfide)s from a common, end-modified precursor poly(disulfide)s. However, this is now established in the current work through a meticulous design of the monomer and polymerization methodology. We anticipate that this versatile and convenient platform will provide access to numerous functional dynamic covalent poly(disulfide)s via minimal synthetic steps.