Density functional theory for soft matter with mesoscopic length scale fluctuations included within field-theoretic formalism

TL;DR

This paper develops a mesoscopic density functional theory incorporating field-theoretic fluctuations for soft matter, predicting a universal phase sequence and complex structures like the gyroid phase based on microscopic interactions.

Contribution

It introduces a systematic coarse-graining approach combining density functional and field theory to predict phase behavior in soft-matter systems.

Findings

Universal phase sequence identified at varying densities

Prediction of complex phases such as the gyroid structure

Dependence of phases on specific interaction potentials

Abstract

Mesoscopic theory for soft-matter systems that combines density functional and statistical field theory is derived from the microscopic theory by a systematic coarse-graining procedure. Within the framework of this theory we obtain the universal sequence of phases: disordered, bcc, hexagonal, lamellar, inverted hexagonal, inverted bcc, disordered, for increasing density well below the close-packing density. In addition to the above phases, more complex phases may appear depending on the interaction potentials. For a particular form of the short-range attraction long-range repulsion potential we find the bicontinuous gyroid phase (Ia3d symmetry) that may be related to a network forming cluster of colloids in a mixture of colloids and nonadsorbing polymers.