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

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.