Parameterized Density Functional Models for Block Copolymer Melts
Abstract
The derivation of density functional energies from the random phase approximation of self-consistent mean field theory is generalized and applied to a binary blend of diblock copolymers and homopolymers. A nonlocal transformation is incorporated into the density functional model prior to the strong segregation extrapolation step employed by Uneyama and Doi. The transformation affords a systematic parameterization of the free energy that preserves key structural features such as scattering structure factor. A simple choice of transformation is shown to incorporate the Tuebner and Strey microemulsion structure factor and provide a reduction to the microemulsion free energy. Without adjustable parameters, the associated phase diagrams are compared to experimental and self consistent mean field based results. A gradient descent of the free energy recovers dependence of end-state morphology on initial configurations, and identifies coexisting microstructures and transitions to two-phase behavior. Small angle x-ray data is simulated and used in classification of microphase morphology.
Cite
@article{arxiv.2307.00659,
title = {Parameterized Density Functional Models for Block Copolymer Melts},
author = {Sulin Wang and Yuan Chen and Zengqiang Tan and Keith Promislow},
journal= {arXiv preprint arXiv:2307.00659},
year = {2023}
}