Toward Hyperuniform Disorder via Self‐Assembly of Bidisperse Colloidal Patterns at an Electrode

Abstract

Abstract While hyperuniform‐disordered patterns have been researched from a theoretical perspective for two decades, large scale experimental realizations remain scarce. In this work, as a potential route to overcome this issue, 2D patterns are evaluated that form through sedimentation of charged particles from a colloidal dispersion at an electrically conductive substrate. The particles are given a sufficient amount of time to form various morphologies and then locked in place irreversibly by setting attractive particle‐substrate potentials. The system can be interpreted as a 2D, however, comparisons to previous numerical works remain qualitative, as the latter do not consider the constant exchange of particles with the 3D bulk of the dispersion. For monodisperse colloids, depending on particle density, random sequential adsorption‐like, fluid, and crystalline phases are obtained, of which the fluid phase most effectively suppresses density fluctuations, or in terms of the hyperuniformity metric HS ≈ 8.7 × 10−3. For bidisperse colloids, the particle sizes tend to segregate at high density thereby reducing the ability of the system to suppress density fluctuations, which are explained within the framework of a eutectic system. The latter also provides hints that the degree of hyperuniformity can be increased by tuning the size distribution to the eutectic point.

Keywords

• crystallization
• electro‐assembly
• eutectic system
• phase segregation
• sedimentation
• self‐organization