Reversible self-assembly of patchy particles into monodisperse icosahedral clusters

TL;DR

This study explores how to design patchy particles that reversibly self-assemble into uniform icosahedral clusters, balancing structural specificity and kinetic accessibility to optimize yield and pathway diversity.

Contribution

It introduces a systematic analysis of patch width and temperature effects on self-assembly, revealing robustness and alternative patch configurations for icosahedral clusters.

Findings

Optimal patch width balances specificity and kinetics.

Assembly pathways include direct nucleation and disordered intermediates.

Robustness to patch placement and alternative patch designs are demonstrated.

Abstract

We systematically study the design of simple patchy sphere models that reversibly self-assemble into monodisperse icosahedral clusters. We find that the optimal patch width is a compromise between structural specificity (the patches must be narrow enough to energetically select the desired clusters) and kinetic accessibility (they must be sufficiently wide to avoid kinetic traps). Similarly, for good yields the temperature must be low enough for the clusters to be thermodynamically stable, but the clusters must also have enough thermal energy to allow incorrectly formed bonds to be broken. Ordered clusters can form through a number of different dynamic pathways, including direct nucleation and indirect pathways involving large disordered intermediates. The latter pathway is related to a reentrant liquid-to-gas transition that occurs for intermediate patch widths upon lowering the temperature. We also find that the assembly process is robust to inaccurate patch placement up to a certain threshold, and that it is possible to replace the five discrete patches with a single ring patch with no significant loss in yield.