Glass transition temperature as a unified parameter to design self-healable elastomers

Self-healing ability of materials, particularly polymers, improves their functional stabilities and lifespan. To date, the designs for self-healable polymers have relied on specific intermolecular interactions or chemistries. We report a design methodology for self-healable polymers based on glass transition. Statistical copolymer series of two monomers with different glass transition temperatures (T_g) were synthesized, and their self-healing tendency depends on the T_g of the copolymers and the constituents. Self-healing occurs more efficiently when the difference in T_g between two monomer units is larger, within a narrow T_g range of the copolymers, irrespective of their functional groups. The self-healable copolymers are elastomeric and nonpolar. The strategy to graft glass transition onto self-healing would expand the scope of polymer design.