Monte Carlo simulations of the temperature-dependent microstructure evolution of relaxor ferroelectric polymers

Abstract

Poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] relaxor ferroelectrics are drawing significant attention nowadays owing to their excellent multifunctionality and extensive applications. However, microstructures responsible for their relaxor behaviors have not been well understood to tailor their application-oriented properties. Monte Carlo (MC) modeling has been developed to successfully reproduce the relaxor ferroelectricity versus normal ferroelectricity of regiodefect-tuned P(VDF-TrFE) polymers. A series of MC simulations was conducted to understand the temperature-dependent microstructure evolutions of both P(VDF-TrFE) relaxor and normal ferroelectrics and further estimate their dielectric permittivity and hysteresis loops. In P(VDF-TrFE) relaxors, their microstructure evolution follows the slush model, involving various nanoscale domains. Significantly, a new phase, a large nanodomain with strongly correlated and randomly oriented dipoles, was found for the first time and is different from the traditional paraelectric phase. Our study not only provides a computational paradigm for ferroelectric polymers but also provides guidance for the design and synthesis of new relaxor polymers by tuning regiodefects.