# Particles with selective wetting affect spinodal decomposition microstructures

## TL;DR

This study uses mesoscale simulations to investigate how immobile particles with selective wetting influence microstructure evolution during spinodal decomposition in ternary mixtures, revealing new effects on structure formation and coarsening.

## Contribution

It introduces novel insights into the effects of strongly wetting particles on microstructure development in spinodal decomposition, including non-bicontinuous to bicontinuous transitions and layer evolution.

## Key findings

- Microstructures are not bicontinuous in symmetric mixtures with particles.
- Asymmetric mixtures evolve from non-bicontinuous to bicontinuous microstructures.
- Late-stage domain growth follows the Lifshitz-Slyozov-Wagner law, R(t) ~ t^{1/3}.

## Abstract

We have used mesoscale simulations to study the effect of immobile particles on microstructure formation during spinodal decomposition in ternary mixtures such as polymer blends. Specifically, we have explored a regime of interparticle spacings (which are a few times the characteristic spinodal length scale) in which we might expect interesting new effects arising from interactions among wetting, spinodal decomposition and coarsening. In this paper, we report three new effects for systems in which the particle phase has a strong preference for being wetted by one of the components (say, A). In the presence of particles, microstructures are not bicontinuous in a symmetric mixture. An asymmetric mixture, on the other hand, first forms a non-bicontinuous microstructure which then evolves into a bicontinuous one at intermediate times. Moreover, while wetting of the particle phase by the preferred component (A) creates alternating A-rich and B-rich layers around the particles, curvature-driven coarsening leads to shrinking and disappearance of the first A-rich layer, leaving a layer of the non-preferred component in contact with the particle. At late simulation times, domains of the matrix components coarsen following the Lifshitz-Slyozov-Wagner law, $R_1(t) \sim t^{1/3}$.