Hydroxypropylcellulose-based liquid crystal materials

Abstract

Hydroxypropyl cellulose is regarded distinctive cellulose derivative due to its unique properties and could display a lyotropic cholesteric liquid-crystalline phase in a variety solvents. This work deals with studying the role of cellulose- and carbon-based nanoparticles on liquid crystal performance of modified hydroxypropyl cellulose (HPC) in lyotropic suspension and nanocomposite films in a comparison study. The lyotropic suspension of HPC and HPC-nanocomposites were characterized by rheological study and optical properties. The Fourier Transformed Infrared Spectroscopy (FTIR), X‐ray Diffractometry (XRD), Thermogravimetric Analysis (TGA), mechanical analysis, scanning electron microscope (SEM) and optical properties were the techniques used to characterize the nanocomposite films. The results showed that, introducing the cellulose and carbon nanoparticles lowered the critical concentration of lyotropic suspension of HPC from 30 wt.% to 26–28 wt.% and earlier appearance of anisotropic phases was occurred which evidenced by the rheological curves and optical properties. The FTIR, XRD and TGA of nanocomposite films showed no change in backbone chemical structure of HPC but the incorporation of nanoparticles, especially cellulose-based NPs, enhanced the crystallinity, thermal stability behaviour and mechanical properties. The behaviour of carbon-NPs in HPC film was unaccepted, where it deteriorated the mechanical properties. The nanocomposite films displayed good fingerprint texture (especially with cellulose nanocrystals) with moderated defined morphologies that promote the liquid crystal nanocomposite development.

Keywords

• Lyotropic liquid crystalline polymer
• Hydroxypropyl cellulose (HPC)
• Cellulose-based nanoparticles
• Carbon-based nanoparticles
• Rheology
• Critical concentration