Oral: Influence of Azobenzene Photoisomerization on Ionic Conductivity

Azobenzene is a well-studied molecule, whose trans-cis isomerization has been employed towards the development of photoswitchable materials. It has been demonstrated that this photoswitching is coupled to changes in intermolecular interactions as well as structural and dynamic changes in host polymer materials, all of which lead to changes in ion transport properties in bulk material. Here, we employ coarse-grained molecular dynamics simulations to investigate the feasibility of using both of these coupling effects synergistically to create light-responsive materials with significant conductivity changes. We examine three azobenzene-functionalized gels swollen with ionic liquid with either: 1) difunctional azobenzene incorporated into the main chain, 2) monofunctional azobenzene in side-chains perpendicular to the chain, and 3) monofunctional azobenzene side-chains with tethered organic cations. These three systems will enable us to decouple the intermolecular and intramolecular influences of isomerization on ionic conductivity. We present our analysis of microscopic structural and dynamic properties from molecular simulations to explain the phenomena observed by experiments. This analysis includes changes in glass transition temperature, nearest neighbor shells, and ionic liquid clustering.