Stable smectic phase in suspensions of polydisperse colloidal platelets with identical thickness

TL;DR

This paper demonstrates the formation of a stable smectic phase in highly polydisperse colloidal platelet suspensions with uniform thickness, combining experimental observations and density-functional theory analysis.

Contribution

It reports the first observation of a stable smectic phase in polydisperse discotic colloids with uniform thickness, supported by experimental and theoretical insights.

Findings

Observation of isotropic--nematic transition with increasing volume fraction

Detection of smectic phase via X-ray, TEM, and optical microscopy

Theoretical explanation of phase behavior using density-functional theory

Abstract

We report the nematic and smectic ordering in a new aqueous suspension of monolayer $\alpha$-Zirconium phosphate platelets possessing a high polydispersity in diameter but uniform thickness. We observe an isotropic--nematic transition as the platelet volume fraction increases, followed by the formation of a smectic, an elusive phase that has been rarely seen in discotic liquid crystals. The smectic phase is characterized by X-ray diffraction, high-resolution transmission electron microscopy, and optical microscopy. The phase equilibria in this highly polydisperse suspension is rationalized in terms of a theoretical approach based on density--functional theory.