Electric Field-Induced Critical Point Shift in a Binary Dielectric Polymer Blend

Phase-separating fluid and polymer mixtures provide a flexible platform for the design of functional materials containing multiple segregated domains. External electric fields provide a modality for biasing this behavior and tuning the miscibility of such mixtures; however, fundamental understanding of electric field effects on phase behavior has been limited by disagreement between theoretical predictions and experimental results.
In this talk, we report progress for a study of binary phase separation in dielectric fluids, performed using a recently developed field theory representation for polarizable molecular species. Polarizability contrast in such systems leads to van der Waals (VDW) interactions that favor immiscibility, inducing aggregation of the more strongly polarizable molecular species, and subsequent demixing. In addition to VDW interactions, which arise from local fluctuations in the polarization of the fluid, the mixture also admits a mean-field dielectric response to the applied field, which favors miscibility of the fluid. The effect of molecular architecture is also considered.