Interfacial layering in a three-component polymer system

TL;DR

This paper theoretically investigates the complex interfacial structure and evolution in a three-component polymer system, revealing layered formations and asymmetric growth driven by contrasting affinities among the species.

Contribution

It introduces a theoretical model for the interfacial dynamics of a three-component polymer system with competing interactions, highlighting novel layered structures and asymmetric growth behaviors.

Findings

Formation of multiple adjacent layers with distinct compositions

Asymmetric growth of the central mixing layer

Potential for unique mechanical properties due to layered structures

Abstract

We study theoretically the temporal evolution and the spatial structure of the interface between two polymer melts involving three different species (A, A* and B). The first melt is composed of two different polymer species A and A* which are fairly indifferent to one another (Flory parameter chi_AA* ~ 0). The second melt is made of a pure polymer B which is strongly attracted to species A (chi_AB < 0) but strongly repelled by species A* (chi_A*B > 0). We then show that, due to these contradictory tendencies, interesting properties arise during the evolution of the interface after the melts are put into contact: as diffusion proceeds, the interface structures into several adjacent "compartments", or layers, of differing chemical compositions, and in addition, the central mixing layer grows in a very asymmetric fashion. Such unusual behaviour might lead to interesting mechanical properties, and demonstrates on a specific case the potential richness of multi-component polymer interfaces (as compared to conventional two-component interfaces) for various applications.