Self-healable ultrahydrophobic modified bio-based elastomer using Diels-Alder ‘click chemistry’

Inclusion of self-healing and water-repellant properties within a commercially available elastomer could be of great significance in prolonging its longevity and sustainability. Herein, Diels-Alder (DA) ‘click’ reaction was employed to introduce self-healing and ultrahydrophobic features in commercially available ENR. In this case, the furfuryl groups were grafted onto the backbone of the pristine elastomer, followed by their DA ‘click’ modification with polyhedral oligomeric silsesquioxane isobutyl maleimide (POSSMI) molecules. Besides the provision of dynamic covalent linkages, the DA modified elastomer showed significantly improved hydrophobicity [water contact angle (WCA) > 140°], because of the presence of nano-sized POSS materials on the surface. In contrast to pristine ENR, the DA adduct POSS hybrid elastomer showed remarkably improved thermal stability, surface hardness, and adhesion to metal substrates. On heating at 120 °C, the furan-maleimide DA covalent linkages cleaved, which re-installed on annealing at 60 °C. In consequence, the DA elastomers exhibited relatively higher mechanical and healing efficacy than the pristine ENR.