Capillary Assembly of Colloids: Interactions on Planar and Curved Interfaces

TL;DR

This paper reviews how capillary interactions at fluid interfaces enable the directed assembly of colloids into organized structures, influenced by interface curvature, particle shape, and surface chemistry.

Contribution

It provides a comprehensive overview of recent advances in understanding capillary assembly mechanisms on planar and curved interfaces.

Findings

Interface curvature guides colloid migration and pattern formation.

Contact line pinning affects assembly configurations.

Curvature acts as an external field influencing structure formation.

Abstract

In directed assembly, small building clocks are assembled into an organized structures under the influence of guiding fields. Capillary interactions provide a versatile route for structure formation. Colloids adsorbed on fluid interfaces distort the interface, which creates an associated energy field. When neighboring distortions overlap, colloids interact to minimize interfacial area. Contact line pinning, particle shape and surface chemistry play important roles in structure formation. Interface curvature acts like an external field; particles migrate and assemble in patterns dictated by curvature gradients. We review basic analysis and recent findings in this rapidly evolving literature. Understanding the roles of assembly is essential for tuning the mechanical, physical, and optical properties of the structure.