Stabilize and Reinforce Hydrogen-Bonded Polymer Complex Elastic Fiber by Catechol Chemistry and Coordination

Hydrogen-bonded polymer complex fiber of poly(ethylene oxide) (PEO) and poly(acrylic acid) (PAA) shows rubber elasticity in ambient environment, but the fiber has relatively low strength and weak stability. We apply the catechol chemistry and metal coordination to stabilize and strengthen the PEO/PAA fiber. PAA is grafted with dopamine (Dopa), and then combines with PEO to prepare fiber. PAA-Dopa in the fiber is cross-linked through oxidation induced dismutation and the metal ions are introduced through coordination. The cross-linking and coordination greatly improve the stability of the fiber against the erosion of alkaline water. Among four different metal coordination fibers, PEO/PAA-Dopa/Cu fiber keeps the excellent extensibility (∼1000%) and presents much higher initial modulus (∼7 MPa), ultimate strength (∼20 MPa), and toughness (∼60 MJ/m³) than its precursor PEO/PAA fiber. In addition, PEO/PAA-Dopa/Cu fiber shows quick recovery and large energy dissipation ratio compared with the PEO/PAA fiber. The distinct mechanical properties enhancement of the hydrogen-bonded complex fiber is attributed to the synergy of hydrogen bonds, coordination and covalent bond cross-linking.