A two-dimensional nematic phase of magnetic nanorods

TL;DR

This paper investigates a hybrid mesophase of magnetic nanorods confined in lamellar layers, demonstrating field-induced ordering and spontaneous in-plane nematic transition, modeled by a two-dimensional Onsager theory.

Contribution

It introduces a novel two-dimensional nematic phase of magnetic nanorods confined in lamellar structures, with experimental measurements and theoretical modeling of their ordering behavior.

Findings

Magnetic nanorods form independent 2D nematic layers.

The in-plane isotropic-nematic transition is first-order.

Magnetic field induces ordering of nanorods within layers.

Abstract

We report a hybrid mesophase consisting of magnetic nanorods confined between the non-ionic surfactant bilayers of a lamellar phase. The magnetic field-induced ordering of the nanorods was measured experimentally and modeled by a two-dimensional Onsager theory including the third virial coefficient. The nanorods are strongly confined in layers, with no orientational coupling from one layer to the next. At high volume concentration they exhibit spontaneous in-plane orientational ordering and form a stack of independent two-dimensional nematic systems. This isotropic-nematic transition is first-order.