Liquid crystalline cellulose-based nematogels

TL;DR

This paper presents a scalable method to create cellulose-based nematogels with tunable optical properties, enabling rapid electric switching and temperature responsiveness for potential use in smart windows and flexible displays.

Contribution

Introduction of a new self-assembled cellulose nanofiber nematogel with tunable optical properties and fast electric switching capabilities.

Findings

Sub-millisecond electric transparency switching

Temperature-responsive optical behavior

Potential applications in smart windows and flexible displays

Abstract

Physical properties of composite materials can be pre-engineered by controlling their structure and composition at the mesoscale. Yet, approaches for achieving this are limited and rarely scalable. We introduce a new breed of self-assembled nematogels formed by an orientationally ordered network of thin cellulose nanofibers infiltrated with a thermotropic nematic fluid. The interplay of orientational ordering within the nematic network and that of the small-molecule liquid crystal around it yields a composite with highly tunable optical properties. By means of combining experimental characterization and modeling, we demonstrate sub-millisecond electric switching of transparency and facile responses of the composite to temperature changes. Finally, we discuss a host of potential technological uses of these self-assembled nematogel composites, ranging from smart and privacy windows to novel flexible displays.