Ultrarobust, Stretchable, and Highly Elastic Supramolecular Elastomer with Hydrogen-Bond Interactions via sp2 Hybridized Boron-Urethane Bonds

Abstract

Elastomers are omnipresent in everyday life and industry, yet the development of an elastomer with both superb stress and toughness presents a prodigious challenge. In this report, a high-strength, tough, and high-elastic elastomer derived from sp² hybrid orbitals of phenylboronic acid was designed. The spatial conformation of network becomes significantly more compact due to the sp² hybridization of boron. This enhances supramolecular hydrogen bonding interactions, resulting in a marked improvement in the material's mechanical properties. Notably, the hydrogen bonding energy in the polyurethane chain segments enhanced by 37%. The robust hydrogen bonding imparts the elastomer with super high true stress (1.30 GPa), superior toughness (442.2 MJ·m⁻³), and super puncture resistance strength of 167.8·N·mm⁻¹. The material exhibited excellent fatigue resistance during continuous tensile cycles, while the irreversible deformation disappeared after standing at room temperature. Moreover, the elastomer bespeaks extraordinary elastic restorability, swiftly reverting to its primitive length after being extended to 16 times. This work provides a strategy that the mechanical properties of materials can be enhanced and toughened by utilizing spatial conformational changes in intermolecular interactions.