Towards a Tetravalent Chemistry of Colloids

TL;DR

This paper introduces a method to create colloids with four-fold valence by coating particles with anisotropic nano-objects, enabling new self-assembly and functionalization possibilities inspired by chemical bonding.

Contribution

It proposes a novel coating strategy for colloids to achieve tetravalent bonding, analyzing defect configurations and methods to control valence states.

Findings

Estimation of nematic Frank constants relevant to coatings

Analysis of defect configurations on spherical colloids

Discussion of methods to achieve different valences

Abstract

We propose coating spherical particles or droplets with anisotropic nano-sized objects to allow micron-scale colloids to link or functionalize with a four-fold valence, similar to the sp3 hybridized chemical bonds associated with, e.g., carbon, silicon and germanium. Candidates for such coatings include triblock copolymers, gemini lipids, metallic or semiconducting nanorods and conventional liquid crystal compounds. We estimate the size of the relevant nematic Frank constants, discuss how to obtain other valences and analyze the thermal distortions of ground state configurations of defects on the sphere.