Synergic Ionic Liquid Systems: Light-Responsive and Self-Healable Poly(Ionic Liquid) Films Incorporating Azobenzene-Based Ionic Liquids

This study details the fabrication and characterization of poly(ionic liquid) (PIL) films incorporating azobenzene-based light-responsive ionic liquids, [AzoC6MIM][TFSI] (AzoIL). The fabricated PIL-AzoIL films exhibit light-induced cis–trans isomerization, leading to differences between ion mobilities and conductivities. Under UV light illumination, the [AzoC6MIM][TFSI] transitions from trans- to cis-form, resulting in polarity changes and increased conductivity. Conversely, visible light induces a return to the trans-form, decreasing the polarity and reducing the conductivities of the PIL-AzoIL films. The PIL-AzoIL films demonstrate enhanced thermal stabilities and light-responsive electrical properties. Moreover, the PIL-AzoIL films present self-healing properties, which can be observed by measuring the electrical and mechanical properties before and after the healing process. Last but not least, the PIL-AzoIL films can be employed as a visual sensor for detecting trifluoroacetic acid vapor.