Supramolecular Polydimethylsiloxane Elastomer with Enhanced Mechanical Properties and Self-Healing Ability Engineered by Synergetic Dynamic Bonds

Abstract

Hydrophobic elastomers are required for use in industry and daily life because of their versatile properties. Developing a hydrophobic elastomer with self-healing abilities and excellent mechanical performance has been very challenging because of the mutually exclusive nature of these properties. Herein, supramolecular polydimethylsiloxane (PDMS) elastomers with excellent self-healing and mechanical properties were designed through the synergetic combination of multistrength H-bonds and disulfide bonds. The hierarchical H-bonds formed with urethane, urea, and 2-ureido-4[1H]-pyrimidinone (UPy) moieties in the backbone of the supramolecular polymer endow the resultant polymers with effective reversible cross-linking, whereas during stretching, the dynamic dissociation and reassociation of H-bonds enable polymers with high extensibility and enhanced toughness and recoverability. In addition, disulfide bond exchange under heat enables polymer network rearrangement, thus imbuing the supramolecular elastomer with excellent self-healing ability. Based on the extraordinary properties of hydrophobic supramolecular PDMS elastomers, some smart materials can be prepared, such as oil/water separation foams and hydrophobic hot-melt adhesives. Therefore, this concept of synergetic dynamic bonds will point out a direction for the development of sustainable, green, and functional materials of the next generation.