Nonequilibrium growth of patchy-colloid networks on substrates

TL;DR

This study explores how nonequilibrium conditions and substrates influence the irreversible self-assembly of patchy colloids, revealing unique fractal networks and optimal mixture compositions that differ from equilibrium structures.

Contribution

It introduces a numerical investigation of nonequilibrium patchy colloid adhesion on substrates, highlighting structural regimes and optimal mixture ratios for enhanced density.

Findings

Fractal network structures with distinct regimes are formed.

An optimal mixture ratio maximizes film density.

Nonequilibrium conditions produce structures different from equilibrium phases.

Abstract

Patchy colloids with highly directional interactions are ideal building blocks to control the local arrangements resulting from their spontaneous self-organization. Here we propose their use, combined with substrates and nonequilibrium conditions, to obtain structures, different from those of equilibrium thermodynamic phases. Specifically, we investigate numerically the irreversible adhesion of three-patch colloids near attractive substrates, and analyze the fractal network of connected particles that is formed. The network density profile exhibits three distinct regimes, with different structural and scaling properties, which we characterize in detail. The adsorption of a mixture of three- and two-patch colloids is also considered. An optimal fraction of two-patch colloids is found where the total density of the film is maximized, in contrast to the equilibrium gel structures where a monotonic decrease of the density has been reported.