Light‐Controllable Ionic Conductivity in a Polymeric Ionic Liquid

Abstract

Polymeric ionic liquids (PILs) have attracted considerable attention as electrolytes with high stability and mechanical durability. Light‐responsive materials are enabling for a variety of future technologies owing to their remote and noninvasive manipulation, spatiotemporal control, and low environmental impact. To address this potential, responsive PIL materials based on diarylethene units were designed to undergo light‐mediated conductivity changes. Key to this modulation is tuning of the cationic character of the imidazolium bridging unit upon photoswitching. Irradiation of these materials with UV light triggers a circa 70 % drop in conductivity in the solid state that can be recovered upon subsequent irradiation with visible light. This light‐responsive ionic conductivity enables spatiotemporal and reversible patterning of PIL films using light. This modulation of ionic conductivity allows for the development of light‐controlled electrical circuits and wearable photodetectors.

Wavelength-selective light-matter interactions in polymer science

“…Ion-transport modulation has been accomplished by Read de Alaniz and coworkers using a wavelength-selective polymer ionic liquid containing positively charged DAE units (DAE-4). 173 The key was tuning the cationic character of the imidazolium bridging group upon photoswitching (Figure 17A). Specifically, openDAE-4 (obtained upon irradiation with visible light) molecules are aromatic and delocalize the positive charge, weakening the ionic interactions.…”

Metal-Containing Poly(ionic liquid) Exhibiting Photogeneration of Coordination Network: Reversible Control of Viscoelasticity and Ionic Conductivity

“…23 Furthermore, the development of photocontrollable soft ionic conductors is an important topic of investigation. There are currently only a few examples of such materials, [24][25][26][27][28] most of which contain photochromic moieties.…”