Interface localisation-delocalisation transition in a symmetric polymer blend: a finite-size scaling Monte Carlo study

Abstract

Using extensive Monte Carlo simulations we study the phase diagram of a symmetric binary (AB) polymer blend confined into a thin film as a function of the film thickness D. The monomer-wall interactions are short ranged and antisymmetric, i.e, the left wall attracts the A-component of the mixture with the same strength as the right wall the B-component, and give rise to a first order wetting transition in a semi-infinite geometry. The phase diagram and the crossover between different critical behaviors is explored. For large film thicknesses we find a first order interface localisation/delocalisation transition and the phase diagram comprises two critical points, which are the finite film width analogies of the prewetting critical point. Using finite size scaling techniques we locate these critical points and present evidence of 2D Ising critical behavior. When we reduce the film width the two critical points approach the symmetry axis $\varphi =1/2$ of the phase diagram and for $D\approx 2R_g$ we encounter a tricritical point. For even smaller film thickness the interface localisation/delocalisation transition is second order and we find a single critical point at $\varphi =1/2$. Measuring the probability distribution of the interface position we determine the effective interaction between the wall and the interface. This effective interface potential depends on the lateral system size even away from the critical points. Its system size dependence stems from the large but finite correlation length of capillary waves. This finding gives direct evidence for a renormalization of the interface potential by capillary waves in the framework of a microscopic model.

Phys.Rev.E

References in corpus (4)

• A symmetric polymer blend confined into a film with antisymmetric surfaces: interplay between wetting behavior and phase diagram
• Non-monotonous crossover between capillary condensation and interface localisation/delocalisation transition in binary polymer blends
• Finite size effects on the phase diagram of a binary mixture confined between competing walls
• Critical-point finite-size scaling in the microcanonical ensemble

Cited by in corpus (8)

• Flat Histogram Method of Wang-Landau and N-fold Way
• Kinetics of Phase Separation in Thin Films: Simulations for the Diffusive Case
• Parameter passing between Molecular Dynamics and continuum models for droplets on solid substrates - The static case
• Study of first-order interface localization-delocalization transition in thin Ising-films using Wang-Landau sampling
• From Capillary Condensation to Interface Localization Transitions in Colloid Polymer Mixtures Confined in Thin Film Geometry
• Phase transitions in nanosystems caused by interface motion: The Ising bi-pyramid with competing surface fields
• Probing interface localization-delocalization transitions by colloids
• Interface repulsion and lamellar structures in thin films of homopolymer blends due to thermal oscillations