Molecular Dynamics Simulation of the Influence of External Electric Fields on the Glass Transition Temperature of the Ionic Liquid 1-Ethyl-3-methylimidazolium Bis(trifluoromethylsulfonyl)imide

We present the results of moleculardynamics simulationsof theionic liquid (IL) 1-ethyl-3-methylimidazolium bis-(trifluoromethylsulfonyl)-imide[C(2)C(1)im]-[NTf2] in the presence ofexternal electric fields (EEFs) of varying strengths to understandthe effects of EEFs on the glass transition temperature T (g). We compute T (g) with an automatedand objective method and observe a depression in T (g) when cooling the IL within an EEF above a critical strength.The effect is reversible, and glasses prepared with EEFs recover theiroriginal zero-field T (g) when heated. Byexamining the dynamics and structure of the liquid phase, we findthat the EEF lowers the activation energy for diffusion, reducingthe energetic barrier for movement and consequently T (g). We show that the effect can be leveraged to drive anelectrified nonvapor compression refrigeration cycle.