Multiple-responsive shape memory polyacrylonitrile/graphene nanocomposites with rapid self-healing and recycling properties

It still remains a great challenge to endow polymer materials with multiple superior material properties by precise molecular design. Herein, we report a Diels–Alder (DA) based crosslinked polyacrylonitrile/graphene nanocomposite (PAN-DA/GR), which has multiple-responsive properties of shape memory, self-healing, and reprocessing in addition to enhanced mechanical properties. The graphene sheets, which are well dispersed in the DA-based crosslinked PAN network, can act as intrinsic localized thermal sources by converting the absorbed external IR/microwave energies into heat, to trigger the glass transition for elasticity-based shape memory properties and retro-DA (rDA) reactions for healing. The incorporation of Diels–Alder bonds also gives the material solid state plasticity through topological network rearrangement, thus leading to versatile shape adaptability. Moreover, both regional shape control and targeted self-healing of the nanocomposites can be simply achieved by IR laser irradiation. Besides, the incorporation of a small amount of graphene can significantly improve the mechanical strength with respect to the DA-based crosslinked PAN. Both DSC and in situ variable temperature (13)C solid-state NMR experiments were used to monitor the reversible DA reactions.