Title: Dithioacetal Bonds as Versatile Building Blocks for Dynamic Polymer Materials

Abstract: Dithioacetal is a well-known protective group in organic synthetic chemistry but have received limited attention in polymer science. Polydithioacetals can be readily synthesized from chain-growth polymerization of dithiols and aldehydes. The dissociation energy of the C-S bond in dithioacetals can be comparable to that of disulfides with adjacent aromatic groups. Despite being labile, dithioacetals are hydrolytically stable. This presentation highlights our recent findings on polydithioacetals capable of reversible entropy-driven ring-opening polymerization (ED-ROP) and ring-closing depolymerization, providing a versatile platform for the development of recyclable polymers. These dynamics behaviors are enabled by acid-catalyzed dithioacetal exchanges. A wide range of topologies, as well as thermal and mechanical properties can be accessed through copolymerization. The syntheses of polydithioacetals, thermodynamics and kinetics of the ring-opening and ring-closing reactions, and the advantages and challenges of ED-ROP for the development of sustainable polymers will be discussed.