Interfacial controllable heterojunctions nanosheets as photothermal catalyzer for cyclic photothermal self-healing of polydimethylsiloxane coating

Abstract

A strategy to improve the number of self-healing cycles of traditional coatings was proposed, in which photothermal nanomaterials were integrated into the self-healing coating to effectively adjust the photothermal response temperature of the coating. Herein, an interface adjustable photothermal heterojunction composed of Bi2MoO6 and hydrothermal carbonation carbon (HTCC) was designed and integrated into polydimethylsiloxane (PDMS) to improve the photothermal self-healing efficiency of the coating. It is found that, by adjusting the interface combination degree, the heterojunction has a broader range of visible light absorption, more photogenerated electron hole pairs, a minor interfacial transfer resistance, and a longer lifetime of photogenerated electron hole pair, causing more photogenerated electrons and holes to have more chances to cross the heterojunction interface and release more heat. The photothermal tests indicate that the temperature of the PDMS-Bi2MoO6@HTCC-0.05 coating quickly reached about 75 °C and exhibited an excellent self-healing performance. The electrochemical tests demonstrate the multiple cycles self-healing performance of the PDMS-Bi2MoO6@HTCC-0.05 coating. In addition, the molecular dynamics calculation results also verified that the PDMS exhibited a higher level of self-healing performance after integrating Bi2MoO6@HTCC-0.05 nanosheets. The concept of adjustable photothermal response temperature coating will enrich the realization of multiple self-healing cycles.