# Cellulose-Refined Cholesteric Liquid Crystal Films with Both Right- and Left-Handed Circularly Polarized Light Reflection

## TL;DR

This paper presents a method to create cellulose-based films that reflect both right- and left-handed circularly polarized light using shear-induced molecular changes.

## Contribution

A novel strategy to produce solid-state cholesteric liquid crystal films with dual-handed CPL reflection using sheared cellulose derivatives.

## Key findings

- Shear-induced optical retardation over 300 nm enables both-handed CPL reflection in CLC films.
- Both right- and left-handed CPL reflection was achieved using HPC and ethyl cellulose derivatives.
- The Sénarmont method confirmed helical molecular distortion under shear.

## Abstract

Biomass-refinery enables sustainable production of viable
fuels
and materials. Cellulose has garnered significant attention as the
most earth-abundant renewable polymer. Hydroxypropyl cellulose (HPC)
derivatives are known to self-organize cholesteric liquid crystal
(CLC) mesophase with right-handed macromolecular sense, leading to
the chiroptical effect of right-handed circularly polarized light
(CPL) reflection. In this report, we establish a promising strategy
to prepare solid-state CLC films with both right- and left-handed
CPL reflection by shearing chemically modified cellulose derivatives.
A key piece of equipment is the rheometer with precisely tunable shear
conditions. Both-handed CPL reflection arises from shear-induced enhancement
in optical retardation over 300 nm by distorting helical molecular
assemblages, as confirmed with the Sénarmont method. The polarization
state of incident light is altered within the film thickness direction.
Moreover, we successfully fabricate intriguing CLC films with both-handed
CPL reflection using inherently right-handed CLCs of the HPC derivative
and also inherently left-handed CLCs of the ethyl cellulose derivative.