Understanding tetrahedral liquids through patchy colloids

TL;DR

This study explores how tuning patch width and range in a model of tetrahedral patchy colloids influences the structure and properties of the resulting networks, providing insights into glass formation in tetrahedral liquids.

Contribution

It introduces a tunable model for tetrahedral colloids that allows detailed analysis of network formation and links to water and silica models, enhancing understanding of glass-forming ability.

Findings

Bonding angle controls network compressibility

Patch angular width affects structure factor pre-peak

Mapping to water and silica models elucidates glass formation

Abstract

We investigate the structural properties of a simple model for tetrahedral patchy colloids in which the patch width and the patch range can be tuned independently. For wide bond angles, a fully bonded network can be generated by standard Monte Carlo or molecular dynamics simulations of the model, providing a neat method for generating defect-free random tetrahedral networks. This offers the possibility of focusing on the role of the patch angular width on the structure of the fully bonded network. The analysis of the fully bonded configurations as a function of the bonding angle shows how the bonding angle controls the system compressibility, the strength of the pre-peak in the structure factor and ring size distribution. Comparison with models of liquid water and silica allows us to find the best mapping between these continuous potentials and the colloidal one. Building on previous studies focused on the connection between angular range and crystallization, the mapping makes it possible to shed new light on the glass-forming ability of network-forming tetrahedral liquids.