The structure of clusters formed by Stockmayer supracolloidal magnetic polymers

TL;DR

This study uses molecular dynamics simulations to explore how different topologies of Stockmayer supracolloidal magnetic polymers self-assemble, revealing that their shape and internal structure depend on topology.

Contribution

It provides new insights into the self-assembly behavior of various SMP topologies without central attraction, highlighting the influence of topology on cluster formation.

Findings

Cluster shape varies with SMP topology

Compact clusters form with isotropic attraction

Internal structure depends on SMP topology

Abstract

Unlike Stockmayer fluids, that prove to undergo gas-liquid transition on cooling, the system of dipolar hard or soft spheres without any additional central attraction so far has not been shown to have a critical point. Instead, in the latter, one observes diverse self-assembly scenarios. Crosslinking dipolar soft spheres into supracolloidal magnetic polymer-like structures (SMPs) changes the self-assembly behaviour. Moreover, aggregation in systems of SMPs strongly depends on the constituent topology. For Y- and X-shaped SMPs, under the same conditions in which dipolar hard spheres would form chains, the formation of very large loose gel-like clusters was observed [Journal of Molecular Liquids, 271, 631 (2018)]. In this work, using molecular dynamics simulations, we investigate self-assembly in suspensions of four topologically different SMPs -- chains, rings, X and Y -- monomers in which interact via Stockmayer potential. As expected, compact drop-like clusters are formed by SMPs in all cases if the central isotropic attraction is introduced, however, their shape and internal structure turn out to depend on the SMPs topology.