Supramolecular Polydimethylsiloxane Elastomer with Enhanced Mechanical Properties and Self-Healing Ability Engineered by Synergetic Dynamic Bonds
Jian Li, Hongyao Niu, Yingfeng Yu, Yulei Gao, Qiang Wu, Fenfen Wang, Pingchuan Sun
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.