Dual stimuli responsive self-healing and malleable materials based on dynamic thiol-Michael chemistry

Thiol-maleimide adducts have been used as dynamic crosslinkers to form soft, elastic, and stimuli responsive polymeric materials. Thiol-Michael adducts can undergo dynamic exchange at elevated temperature or elevated pH values. Due to the dynamic behaviour of thiol-Michael adducts, crosslinked polymeric materials display significant healing after cutting into half, and malleability upon exposure to solutions of elevated pH. These materials are also thermally responsive, showing self-healing properties and malleability at high temperatures (90 °C). The self-healing properties of these polymer materials are significantly higher than materials with non-dynamic crosslinkers. In addition, in mechanical stability experiments, these materials showed creep resistance and complete creep recovery at room temperature and pressure. These results indicate that the thiol-Michael reaction is dynamic and reversible in response to thermal and pH stimuli. These stimuli responsive self-healing, elastic, malleable, and mechanically stable polymeric materials open the door to have potential utilization in different applications such as coatings or elastomers with extended lifetimes.