Superior liquid crystal properties of nanochitin-graphite oxide based nanocomposites

Abstract

Lowering the critical concentration required for liquid crystal (LC) phase formation is essential for improving the performance and economic feasibility of LC-based nanobiomaterials. In this study, the effect of graphite oxide (GO) on the optical behaviour of chitin nanoparticle (Ch-NP) precursors was investigated. Chitin nanoparticles were prepared using two different methods: conventional acid hydrolysis (Ch-NP) and microwave-assisted extraction (MCh-NP). The obtained nanoparticles and their GO-based hybrids were characterized using Transmission Electron Microscopy (TEM), Attenuated Total Reflection–Fourier Transform Infrared Spectroscopy (ATR-FTIR), X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA), and Polarizing Optical Microscopy (POM). The results indicate that microwave-assisted processing improves the structural and optical properties of the nanoparticles. MCh-NPs exhibited a higher crystallinity index (84.01%) compared with Ch-NPs (81.2%), along with a significantly lower critical concentration for LC phase formation (1 wt% versus 5 wt%). Furthermore, incorporating GO at a ratio of 5:95 (GO:chitin) enhanced the crystallinity and optical characteristics of the resulting nanocomposites. TEM observations revealed differences in particle morphology and size distribution between the Ch-NP and MCh-NP based hybrids. Notably, the addition of GO dramatically reduced the critical LC phase concentration to 0.05 wt%, which is lower than previously reported values in the literature. These findings highlight the potential of combining microwave-assisted chitin nanoparticles with GO to develop highly efficient LC nanobiomaterials.