Biomimetic Hybrid Networks with Excellent Toughness and Self-Healing Ability in the Glassy State

Loose connective tissue that widely exists in the human body is very tough and healable, due to the unique network formed by hyperbranched and linear fibers. Inspired by such structure, we develop a class of tough and healable polymeric glasses (THGs) by tailoring amine-carboxylate salt bridges between a hyperbranched polymer and high-molecular-weight linear copolymers. The high density of salt bridges leads to high yield strength (up to 49.7 MPa) and Young's modulus (1.1 GPa) of THGs. Meanwhile, the large free volume of the hyperbranched polymer and the molecular entanglements of the linear copolymers enable outstanding toughness (up to 91.9 MJ/m3), outperforming most commercial glassy polymers. More interestingly, THGs can be readily healed below and around the glass-transition temperature after mechanical damage. Therefore, this biomimetic approach enables the development of glassy polymers with combination of high strength, excellent toughness, and self-healing ability.