Sulfur-Based Dynamic Covalent Polymers: From Reversible Bonds to Smart Materials

Dynamic covalent bonds (DCBs), known for their reversible cleavage and reformation under stimuli, have become a key focus in polymer science for designing adaptive materials. Among various dynamic motifs, sulfur is particularly notable for its abundance and versatile chemistry. Incorporating sulfur-based DCBs into polymer networks enables the creation of covalent adaptable networks (CANs) that combine the robustness of thermosets with the reprocessability of thermoplastics. This synergy imparts transformative functions such as self-healing, shape memory, and controllable degradation, addressing environmental challenges in material lifecycle. This minireview centers on sulfur chemistry, systematically elucidating the exchange mechanisms, characteristics, and applications of key sulfur-containing DCBs, including dynamic sulfur–sulfur or sulfur–selenium exchange, dynamic thioester exchange, reversible thiol-Michael addition, dynamic thioacetal exchange, dynamic thiocarbamate exchange, dynamic thiourea exchange, dynamic trithiocarbonate exchange, dynamic benzyl sulfide exchange, dynamic disulfenamide-amine exchange, dynamic NOS exchange, and dynamic sulfur-phenolate exchange. We compare the factors governing their dynamic behavior and illustrate how rational bond design enables precise control over material properties. Finally, current challenges and future perspectives are discussed, aiming to guide the development of next-generation sustainable, adaptive, and intelligent polymeric materials.