作者:Ying Yang、Dmitriy Davydovich、Chris C. Hornat、Xiaolin Liu、Marek W. Urban
DOI:10.1016/j.chempr.2018.06.001
日期:2018.8
Hierarchical multiphase fibrous morphologies provide strength and elasticity for biological species, facilitating responses to environmental changes. Wound closure of leaves is one example. If polymers can be formed in a similar manner by introducing multiphase-separated morphologies, self-healing in a variety of commoditymaterials can be achieved. In these studies, we demonstrate the role of phase morphologies, interphases, and viscoelasticity-driven shape memory effects on self-healing. We synthesized phase-separated polycaprolactone-polyurethane fibrous thermoplastic polymers in which microphase separation facilitates the formation of stable interfacial regions between hard and soft segments. Self-healing can be repeated many times. This behavior is attributed to the shape memory effect, given that micron-scale interphase reduces chain slippage, enabling entropic energy storage during damage. Chemically identical but nanophase-separated copolymers do not exhibit this behavior. These studies show that self-healing can be achieved by morphology control and facilitated by thermal or other volume-induced transitions.