Self-healing polymers with microphase-separated structure are plagued with inferior self-healing efficiency at room temperature due to a lack of dynamic interactions in hard domains. Herein, we describe a novel strategy of multiphase active hydrogen bonds (H-bonds), toward realizing fast and efficient self-healing at room temperature, even under harsh conditions. The core conception is to incorporate thiourea moieties into microphase-separated polyurea network to form multistrength H-bonds, which destroy the crystallization of hard domains and, at the same time, insert the dynamic reversible H-bonds in both hard and soft segments, accounting for the surprisingly self-healing performances. The synthesized polymeric material, poly(dimethylsiloxane)–4,4′-methylenebis(phenyl isocyanate)–1,1′-thiocarbonyldiimidazole, completely recovers all of the mechanical properties within 4 h at room temperature after rupture. Significantly, self-healing process can also take place at low temperature (restoration with an 85% efficiency in 48 h at −20 °C) or in the water (restoration with a 95% efficiency in 4 h). Depending on the cleavage/reformation of multiphase H-bonds, the material exhibits unprecedented ultrastrechability and notch-insensitiveness. It can be stretched up to 31 500% without fracture and reach a notch-insensitive stretching of up to 18 000%. These exceptional characteristics inspired us to fabricate highly stretchable self-healable underwater conductor and protective self-healing film for suppressing shuttling of polysulfides and preventing crack propagation in S cathode, which provide the pathway for applications in underwater electronic devices or advanced Li–S batteries.

原文链接

https://pubs.acs.org/doi/10.1021/acs.chemmater.9b02136