Tough silicone-based elastomers enhanced by synergistic Zn(ii)–carboxylate interactions and weak hydrogen bonds between incompatible soft segments†

Abstract

Achieving an optimal combination of high toughness, healability, and recyclability in silicone-based elastomers remains a significant challenge, primarily attributed to the inherently weak interactions between polysiloxane molecules. Herein, a thermoplastic poly(silicone-urea) elastomer exhibiting superior mechanical properties is developed by optimizing the synergistic Zn(II)–carboxylate interactions and weak hydrogen bonds between thermodynamically incompatible poly(dimethylsiloxane) (PDMS) and poly(propylene glycol) (PPG). Despite their distinct polarities, PDMS and PPG are chemically constrained, leading to microphase separations exclusively at the nanoscale. Furthermore, the hard segment comprises discrete and small hydrogen-bonding domains and metal-coordination domains. The forced compatibility and spontaneous phase separation of soft segments, in conjunction with the superimposed reversibility of discrete hard segment regions, can cooperatively dissipate energy during elastomer deformation. The obtained elastomer demonstrates a remarkable toughness of 69.9 MJ m⁻³, an exceptional stretchability of 2259%, and good elastic recovery under small deformation (≤300%) while preserving good recyclability and healability. These properties position the elastomer as a promising candidate for applications in flexible electronic devices, thereby contributing to the development of a sustainable society.