Investigation of the mesogenic behavior of alkoxy and fluorine tail terminated alkoxy nitrobiphenyls for chemoresponsive liquid crystals

ABSTRACT

Liquid crystal properties of compounds with a variety of polar terminal groups including cyano, fluoro, isothiocyanato, etc., were studied well, however, not enough attention was given to nitro terminal compounds. In this work, a series of fluorine tail terminated alkoxy nitrobiphenyl compounds were synthesised and their mesogenic properties were analysed. In addition, the simple alkoxy nitrobiphenyl compounds were synthesised and analysed in order to compare them with fluoro-alkoxy nitrobiphenyl compounds and for binary mixture analysis. Fluorine tail termination to the alkoxy chain does suppress the smectic phase that was observed for the simple alkoxy nitrobiphenyl compounds with longer chains. Fluorine tail terminated alkoxy nitrobiphenyl compounds with longer chains (C7-C10) show monotropic nematic phase around ambient temperature and supercooling properties and these compounds are useful for a binary mixture analysis. Moreover, computation and experimental analyses of the alkoxy nitrobiphenyl compounds were performed to investigate the potential use of these nitro terminal compounds as chemoresponsive liquid crystal materials.

GRAPHICAL ABSTRACT

KEYWORDS:

• Nitrobiphenyl
• tail fluorinated alkoxy
• nucleophilic substitution reaction (S_N2)
• nematic phase
• homeotropic anchoring
• chemoresponsive sensor

Disclosure statement

Prof. Nicholas L. Abbott declares a financial interest in Platypus Technologies LLC, a for‐profit company that has developed LC‐based analytic technologies for conflicts of interest.

Additional information

Funding

This work was supported by three grants from the National Science Foundation (DMR-1921696, DMR-1921722, and DMR-1921668). Part of the computational work conducted by T.W. and M.M. in this study was carried out through external computational resource facilities at the National Energy Research Scientific Computing Centre (NERSC) through the U.S. DOE, Office of Science under Contract No. DE-AC02-05CH11231; and the Centre for Nanoscale Materials (CNM) at Argonne National Laboratory (ANL) through the U.S. DOE, Office of Science under Contract No. DE-AC02-06CH11357.