Fluctuation effects in ternary AB+A+B polymeric emulsions

TL;DR

This paper introduces a Monte Carlo simulation method to study thermal fluctuation effects in a ternary polymer blend, revealing shifts in phase transition lines and evidence of microemulsion phases consistent with experiments.

Contribution

The paper develops a Monte Carlo approach for field theories of polymeric fluids, capturing fluctuation effects and phase behavior beyond mean-field approximations.

Findings

Shift in order-disorder transition lines due to fluctuations

Identification of bicontinuous microemulsion phase near Lifshitz point

Agreement with experimental observations of phase behavior

Abstract

We present a Monte Carlo approach to incorporating the effect of thermal fluctuations in field theories of polymeric fluids. This method is applied to a field-theoretic model of a ternary blend of AB diblock copolymers with A and B homopolymers. We find a shift in the line of order-disorder transitions from their mean-field values, as well as strong signatures of the existence of a bicontinuous microemulsion phase in the vicinity of the mean-field Lifshitz critical point. This is in qualitative agreement with a recent series of experiments conducted with various three-dimensional realizations of this model system. Further, we also compare our results and the performance of the presently proposed simulation method to that of an alternative method involving the integration of complex Langevin dynamical equations.