Dynamic Thiol–Michael Chemistry for Thermoresponsive Rehealable and Malleable Networks

Abstract

The thiol–Michael adduct is used as a thermoresponsive dynamic cross-linker in polymeric materials. Recently, the thiol–Michael reaction between thiols and conjugated alkenes has been used as a ligation reaction for polymer synthesis and functionalization. Here, the thiol–Michael reaction is demonstrated to be thermally responsive and dynamic. Small molecule model experiments demonstrate the potential for the thiol–Michael adducts to be used in dynamic covalent chemistry. Thiol–acrylate adducts are incorporated into a cross-linker to form a soft polymeric material. These thiol–Michael cross-linked materials display healing after being cut and malleability characteristics at 90 °C. Additionally, the data suggest that there is limited creep and stress relaxation at room temperature with complete recovery of creep once the strain is removed. These thiol–Michael cross-linked polymers show dynamic properties upon thermal stimulus, with long-term stability against mechanical deformation in the absence of this s...