Force-induced desorption of uniform block copolymers

TL;DR

This paper rigorously analyzes how uniform block copolymers adsorb and desorb under force using self-avoiding walk models, revealing phase diagram structures and a novel mixed phase.

Contribution

It provides the first rigorous analysis of a self-avoiding walk model for force-induced desorption of block copolymers, including phase diagram characterization.

Findings

Dependence of free energy on adsorption and force parameters

Identification of phase diagram structures for different copolymer types

Discovery of a novel mixed phase in the model

Abstract

We investigate self-avoiding walk models of linear block copolymers adsorbed at a surface and desorbed by the action of a force. We rigorously establish the dependence of the free energy on the adsorption and force parameters, and the form of the phase diagram for several cases, including $AB$-diblock copolymers and $ABA$-triblock copolymers, pulled from an end vertex and from the central vertex. Our interest in block copolymers is partly motivated by the occurrence of a novel mixed phase in a directed walk model of diblock copolymers \cite{Iliev} and we believe that this paper is the first rigorous treatment of a self-avoiding walk model of the situation.