Equilibrium of Free Surfaces and Nanoparticles in Self-Consistent Field Theory of Block Copolymers

TL;DR

This paper develops a comprehensive self-consistent field theory for block copolymer self-assembly near free surfaces and nanoparticles, accommodating complex geometries, surface energies, and grafting conditions, with applications demonstrated through various examples.

Contribution

It introduces a unified, general theory that handles diverse boundary conditions and particle shapes in block copolymer self-assembly, including triple-junction points and singularity-free pressure fields.

Findings

Successfully models meniscus formation in graphoepitaxy

Describes co-assembly of nano-rods and copolymer melts

Provides a boundary condition imposition procedure for complex surfaces

Abstract

This work presents a general and unified theory describing block copolymer self-assembly in the presence of free surfaces and nanoparticles in the context of Self-Consistent Filed Theory. Specifically, the derived theory applies to free and tethered polymer chains, nanoparticles of any shape, arbitrary non-uniform surface energies and grafting densities, and takes into account a possible formation of triple-junction points (e.g., polymer-air-substrate). One of the main ingredients of the proposed theory is a simple procedure for a consistent imposition of boundary conditions on surfaces with non-zero surface energies and/or non-zero grafting densities that results in singularity-free pressure-like fields, which is crucial for the calculation of forces. The generality of the theory is demonstrated using several representative examples such as the meniscus formation in the graphoepitaxy and the co-assembly of "polarized" nano-rods and diblock copolymer melts.