Microphase morphology in two dimensional fluids under lateral confinement

TL;DR

This study investigates how lateral confinement influences the microphase morphology of a two-dimensional fluid with competing interactions, revealing temperature-dependent structural transitions and orientation changes of micro-domains.

Contribution

It demonstrates the impact of confinement and temperature on microdomain structures, including novel temperature-induced transitions not observed in bulk fluids.

Findings

Neutral walls induce a switch from stripes to droplets at lower temperatures.

Stripe orientation can change from parallel to perpendicular due to confinement.

Mixed microdomain morphologies can be stabilized depending on parameters.

Abstract

We study the effects of confinement between two parallel walls on a two dimensional fluid with competing interactions which lead to the formation of particle micro-domains at the thermodynamic equilibrium (microphases or microseparation). The possibility to induce structural changes of the morphology of the micro-domains is explored, under different confinement conditions and temperatures. In presence of neutral walls, a switch from stripes of particles to circular clusters (droplets) occurs as the temperature decreases, which does not happen in bulk. While the passage from droplets to stripes, as the density increases, is a well known phenomenon, the change of the stripes into droplets as an effect of temperature is rather unexpected. Depending on the wall separation and on the wall-fluid interaction parameters, the stripes can switch from parallel to perpendicular to the walls and also a mixed morphology can be stable.