Biological systems are able to self-repair repeatedly and autonomously on multiple scale lengths, from DNA macromolecules to larger organs, such as veins, soft or hard tissues, and muscles. Leaf plants encode self-healing functions by incorporating viscoelastic responses to their tissue during growth, thus enabling deformations upon mechanical damage to close a wound. While numerous studies have shown that chemical modifications may be successful in achieving self-healing properties, the role of phase morphologies, viscoelasticity-driven shape memory effects and copolymer compositions was only recently explored. At micro scale, the formation of stable interfacial regions between hard and soft segments can facilitate efficient self-healing resulting from reduced chain slippages during damage in polycaprolactam-polyurethane (PCL-PU) polymers. In other studies we have shown that predominantly alternating chain segments create favorable interchain van der Waals forces forming “key-and-lock” interchain junctions within narrow molar compositional range of poly(methyl methacrylate)/n-butyl acrylate [p(MMA/nBA)] copolymer and its derivatives. The perturbation of ubiquitous van der Waals forces upon mechanical damage facilitates energetically unfavorable for interdigitated alternating/random copolymer motifs, thus enabling self-healing under ambient conditions. Although significantly different in terms of scale length, illustrate that self-healing can be achieved by controlling phase morphologies or chain topologies in commodity material and the use of van der Waals forces enables multiple recovery upon mechanical damage without external intervention.

Self-healing commodity copolymers

2019 Spring National Meeting

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