Self-healing poly(siloxane-urethane) carbon nanotube composites with multi-band repairing capability and efficient recovery have significant photothermal response

Polymer silicone elastomers have attracted extensive attention in fields such as human- computer interaction and health monitoring. However, traditional silicone materials are prone to irreversible damage during usage, and most of them can only self-healing under ultraviolet light of specific unfriendly wavelengths. This is harmful to the user’s health and restricts their application in multi-band exposure scenarios. Hence, there is an urgent necessity to explore materials that can self-healing under diverse conditions. In this research, carbon nanotubes (CNTs) were integrated as a photothermal conversion agent into self-healing poly(siloxane-urethane) (PSiUe) materials to fabricate a poly(siloxane-urethane)-carbon nanotube composite (PSiUe-CNTs) with multi-band self-healing properties. The impacts of different CNTs contents on the mechanical properties, self-healing properties, and thermal stability of the PSiUe-CNTs composites were investigated. By analyzing the mechanical properties of the composites with different CNTs content, it is found that the composites exhibit excellent mechanical properties when the CNTs content is 8%. Further analysis of mechanical properties before and after self-healing showed that PSiUe-CNTs were in ultraviolet light (365 nm), visible light (400–760 nm), near-infrared light (0.78–1.4 μm), and far-infrared light (25–1000 μm) under exposure can reach more than 90% self-healing efficiency in 6-h repair time, which achieve multi-band self-healing. By comparing the results of the analysis of the elements near the scratch, it is proved that the content of N, O, and Fe elements has been increased to different degrees. In addition, the recyclability analysis showed that the recyclability of the composites was excellent, with recovery efficiency above 90%. Therefore, this unique multi-stimulus-responsive self-healing polymer material can fulfill the requirements of various application scenarios, especially those closer to sunlight, and shows broad application prospects.

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