Self-healable copolymers via van der Waals interactions
November 10-14, 2019
In these studies we developed fluoro-containing copolymers that for well-defined monomer molar ratios exhibit autonomous self-healing. This behavior is attributed to inter-digitated copolymer topologies facilitated by van der Waals (vdW) interactions. The main feature of vdW interactions is large polarizability (hydrophobicity) which in thermoplastic polymers leads to non-directional interactions between neighboring macromolecular segments. However, dipole-dipole directionality of the side groups can be enhanced by alternating/random copolymer compositions resulting from inter-chain vdW forces. Upon mechanical damage macromolecular segments will energetically favor original inter-chain conformations and return to original conformations, thus self-heal. Using chemical imaging (IR) and 1H NMR spectroscopy (NOESY, COSY) through-space and through-bond interactions were identified and used as input to molecular dynamic (MD) simulations in an effort to identify molecular events governing self-healing behavior.
Siyang Wang and Dmitriy Davydovich, "Self-healable copolymers via van der Waals interactions" in "Composites at Lake Louise 2019", John Kieffer, University of Michigan, USA Erik Spoeke, Sandia National Laboratories, USA Meisha Shofner, Georgia Institution of Technology, USA Eds, ECI Symposium Series, (2019). https://dc.engconfintl.org/composites_all_2019/9