Jumping In and Out of the Phase Diagram Using Electric Fields: Time Scale for Remixing of Polystyrene/Poly(vinyl methyl ether) Blends.

We demonstrate it is possible to repeatedly jump polystyrene (PS)/poly(vinyl methyl ether) (PVME) blends from the one-phase to two-phase region by simply turning on and off an electric field at a fixed temperature near the phase boundary. This builds on our previous work that established electric fields enhance the miscibility of PS/PVME blends by shifting the phase separation temperature T S ( E ) of 50/50 blends up by 13.5 ± 1.4 K when field strengths of E = 1.7 × 10 7 V/m are applied ( J. Chem. Phys. 2014 , 141 , 134908). Monitoring the early stages of phase separation and remixing by fluorescence, we measure the remixing time scale τ( T ) with and without electric fields, finding τ( T ) is unchanged by the presence of the field and well fit by a Vogel-Fulcher-Tammann expression. These observations are consistent with a mobility-limited process several degrees from the phase boundary where electric fields have shifted the miscibility transition.