A super-stretched self-healing silicone elastomer based on high molecular weight polydimethylsiloxanes through intermolecular quadruple hydrogen bonding

Supramolecular silicone elastomer is a promising material for sustainable development. Here, quadruple hydrogen bonded ureidopyrimidinone (UPy) units were grafted onto high molecular weight polydimethylsiloxanes (PDMS), providing a novel supramolecular silicone elastomer. The high molecular weight PDMS precursor was prepared through a cyclic trimeric phosphazene base catalyzed ring-opening polymerization of Octamethylcyclotetrasiloxane (D-4) and tetravinyltetramethylcyclotetrasiloxane (V-4) with a well-controlled vinyl content. Its side chains were modified by hydroxyl groups via a thiol-ene reaction. Then UPy units were further grafted on the side chain of high molecular weight PDMS by the isocyanate-hydroxy reaction. The mechanical and self-healing properties of the elastomer can be controlled by adjusting the molecular weight of PDMS and the amount of UPy units. The obtained PDMS elastomers displayed excellent stretchability (elongation at break of 1513%), good self-healing efficiency (76% at 60? for 2 h), and high resilience (elastic recovery of 93% under 300% strain cyclic stretching).