Azobenzene-containing liquid crystalline composites for robust ultraviolet detectors based on conversion of illuminance-mechanical stress-electric signals

Wearable polymer ultraviolet (UV) detectors seriously suffer from slow response time. Here, the authors propose a UV illuminance-mechanical stress-electric signal conversion based on well-defined ionic liquid-containing liquid crystalline polymer and highly elastic polyurethane composite fabrics, to achieve a robust UV monitoring and shielding device with a fast response time of 5 s. Wearable ultraviolet (UV) detectors have attracted considerable interest in the military and civilian realms. However, semiconductor-based UV detectors are easily interfered by elongation due to the elastic modulus incompatibility between rigid semiconductors and polymer matrix. Polymer detectors containing UV responsive moieties seriously suffer from slow response time. Herein, a UV illuminance-mechanical stress-electric signal conversion has been proposed based on well-defined ionic liquid (IL)-containing liquid crystalline polymer (ILCP) and highly elastic polyurethane (TPU) composite fabrics, to achieve a robust UV monitoring and shielding device with a fast response time of 5 s. Due to the electrostatic interactions and hydrogen bonds between ILs and LC networks, the ILCP-based device can effectively prevent the exudation of ILs and maintain stable performance upon stretching, bending, washing and 1000 testing cycles upon 365 nm UV irradiation. This work provides a generalizable approach toward the development of full polymer-based wearable electronics and soft robots.

Automated summary

The study introduces a UV radiation detection device based on composite fabrics, utilizing ionic liquid and liquid crystal polymer materials to achieve fast response and stable operation in various complex environments. This device provides a generalizable approach for the development of full polymer wearable electronics and soft robots.