Using Molecules with Superior Water-Plasticity to Build Solid-Phase Molecular Self-Assembly: Room-Temperature Engineering Mendable and Recyclable Functional Supramolecular Plastics

Abstract

The brittleness of many supramolecular films in a dry environment has prevented their further application as supramolecular plastics. We report here the fabrication of supramolecular plastics displaying excellent dry-flexibility and mechanical strength through room-temperature solid-phase molecular self-assembly using water-locking polyelectrolyte and surfactant. Aided by mild mechanical pressure of about 0.5 MPa, the locked water enables the polyelectrolyte-bridged surfactant microdomains to merge into large mesophases to reduce the interface energy, which yields a transparent supramolecular film. The film still contains 2% water in a dry environment, which is capable of plasticizing the polyelectrolyte and surfactant; thus, it imparts excellent flexibility to the film. The dry film has a stress of 12 MPa and Young’s modulus of 188 MPa with a strain of 24%. This mechanical strength is comparable to that of the commercial soft polyethylene plastics. Since the noncovalent interactions in the film can be activated by water under mild mechanical pressure within seconds, mending a broken film by pressing a wet patch with mild mechanical force onto the damage becomes possible. Complete recycling can be achieved under the same conditions. We envision the current room-temperature mechanical force driven water-based recyclable and mendable supramolecular plastics would be very promising in reducing white pollution and generating integrated materials.