New room temperature nematogens by cyano tail termination of alkoxy and alkylcyanobiphenyls and their anchoring behavior on metal salt-decorated surface

ABSTRACT

A series of cyano tail-terminated alkoxy and alkyl cyanobiphenyl compounds and some cyano-p-terphenyl derivatives were synthesized and mesogenic properties described. Comparison with the K series and M series indicates that the terminal cyano group generally enhances the supercooling of the molecules. Furthermore, several binary LC mixtures formed by the cyano tail-terminated compounds were found exhibiting promising room temperature nematic phases ranges comparable to the commercial quaternary mixture E7. The equimolar binary mixture of CN5OCB and CN7OCB shows homeotropic ordering at the metal salts-decorated surfaces and planar ordering at the free surface, which is consistent with G_BE values we calculated. As such, these materials are promising candidates for sensor devices which display a rapid response to a variety of analytes.

Graphical Abstract

KEYWORDS:

• Room temperature
• nematogens
• cyano tail termination
• cyanobiphenyls
• anchoring behavior

Acknowledgments

This work was supported by the National Science Foundation (DMREF grant DMR-1435195) and the Army Research Office (W911NF-14-1-0140). Part of the computational work conducted by T.S., J.I.G and M.M. in this study was carried out through external computational resource facilities at: the DoD High Performance Computing Modernization Program (US Air Force Research Laboratory DoD Supercomputing Resource Center (AFRL DSRC), the US Army Engineer Research and Development Center (ERDC), and the Navy DoD Supercomputing Resource Center (Navy DSRC), ARONC43623362), supported by the Department of Defense; the National Energy Research Scientific Computing Center (NERSC) through the U.S. DOE, Office of Science under Contract No. DE-AC02-05CH11231; and the Center for Nanoscale Materials (CNM) at Argonne National Laboratory (ANL) through the U.S. DOE, Office of Science under Contract No. DE-AC02-06CH11357.

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.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

This work was supported by the Army Research Office [W911NF-14-1-0140 and W911NF-19-1-0071] and the National Science Foundation [DMR-19022683 and DMR-1435195].