Reprocessable supramolecular polymer adhesives for on-demand adhesion in multiple scenarios

Abstract

Supramolecular polymer adhesives (SPA) based on dynamic non-covalent interactions exhibit a wide range of potential applications. However, achieving on-demand adhesion by precisely adjusting non-covalent interactions to achieve successful adhesion in a variety of situations has long been a challenge. Here we report a facile method to develop SPA based on natural molecules of lipoic acid (LA) and hydroxypropyl β-cyclodextrin (hCD) with tailored adhesion behavior and unique time-temperature dependent characteristics for on-demand adhesion in multiple scenarios. Through the balance between dynamic non-covalent bonds (hydrogen bonds) and dynamic covalent bonds (disulfide bonds), the depolymerization of poly(LA) can be precisely regulated rather than completely inhibited. The resultant SPA exhibits unique physical properties (gradual transformation from a semicrystalline to an amorphous state) and tunable adhesion strength (from 0.365 MPa to 6.429 MPa). Moreover, the resultant SPA is not only solvent-free, recyclable and reusable, but also has good processability, self-healing and wet adhesion abilities, and on-demand adhesion behavior with various substrates with different stiffnesses and moduli, thus opening it up to applications in a wide range of scenarios.