Robust Self-Healing PDMS-Based Elastomers Featuring Tunable Mechanical Properties Enabled by Dual Non-Covalent Interactions.

Abstract

It is desirable to develop highly efficient self-healing polydimethylsiloxane (PDMS) elastomers with excellent mechanical properties, which can be solved by introducing dual non-covalent interactions. However, most of the self-healing PDMS elastomers reported so far require harsh conditions, while the improvement of self-healing ability often compromises the mechanical properties. Moreover, hydrogen bonds of traditional urea derivatives tend to crystallize excessively, adversely affecting the stretchability and toughness of elastomers. In this work, strong Zn²⁺ coordination is introduced into a thiourea hydrogen bond network, which is unlikely to crystallize, resulting in a series of robust and efficient self-healing elastomers. By changing the content of Zn²⁺ ions, the mechanical properties of materials can be strategically tuned from superior stretchability (≈6000%) to high strength (≈4.2 MPa). In addition, the elastomers also possess favorable self-healing ability. The surface scratches can be completely healed at room temperature for 24 h, and the self-healing efficiency of mechanical properties under mild conditions (60 °C, 6 h) generally reached more than 90%. In addition, the applications of PDMS-BDTI-Zn on hydrophobic coatings are tentatively explored in view of the remarkable hydrophobicity of PDMS.