H-bonded liquid crystals: effect of ZnO nanoparticles on the enhancement in electrical conductivity

Abstract Integrating nanoparticles (NPs) with liquid crystals has emerged as a contemporary research domain in soft matter. The interplay between the two can substantially transform their properties and dynamics. The study conducted the experiments using nanocomposites of hydrogen-bonded supramolecular calamitic liquid crystals doped with ZnO NPs. It is found that the concentration of ZnO and the carbon chain length of the host compounds played a significant role in determining the mesophase transition and crystallization temperatures. The study aimed to investigate the effect of NPs on the electrical properties of liquid crystal nanocomposites, using varying weight percentages (0.5wt%, 2wt%, and 5wt%). Zinc oxide NPs with a particle size of 118 nm is synthesized using a simple starting material. Hydrogen-bonded liquid crystals (HBLCs) viz., P8:FBA and P18:FBA with chain lengths of 8 and 18 carbons, obtained from acid moieties and Schiff bases acted as a host. The nanocomposites exhibited enhanced conductivity with the increase in the dopant concentration while the conductivity decreased as the chain length increased from 8 to 18. It is believed that an increased concentration of NPs increases conductivity through the ion hopping pathway. Adding ZnO NPs to the host HBLC reduces the activation energy and enhances conductivity, making it suitable as functional materials.