Perspective on structure-property relationship of room temperature single-component liquid crystals

ABSTRACT

Ever since the serendipitous discovery of liquid crystals (LC) by Friedrich Reinitzer in 1888, a significant number of LCs have been synthesised and characterised. The ever-growing LCs emanating from conventional and non-conventional systems find applications in various electronic appliances such as flat-panel TV displays, notebooks, digital cameras, and domestic devices. The room temperature LCs (RT-LCs 20 to ±80 °C), either as single-component/composites, act as a starting point for such applications. Therefore, the quest for such RT-LCs is always valued and carved out as a promising niche for many such devices. Molecular design and the structure-property relationship are the recurrent themes for stable and single-component RT-LCs. The LC molecules starting from simple benzenoids to macrocycles with flexible hydrocarbon chains as spacer/terminal tails needed to be tethered in a precise pattern may lead to potential LCs. To craft stable and single-component RT-LCs, functional groups (nitrile, halogens, nitro, aldehydes, amine, thiol, alcohol, ketone, ester, amide) are frequently employed. RT-LCs with viscosity, dielectric, birefringence, and polarity enables the reduction of the number of components in a composites mixture. This review describes the genesis and importance of the single component RT-LCs, state-of-the-art LC research, perspectives, and new design strategies for venturing into a new horizon.

Graphical abstract

• Elucidation of the design principles for molecular structure-based liquid crystals (LCs) and compiled the existing single component thermotropic (SLCs) based on the overview from literature. • Room temperature thermotropic LCs (RT-LCs 20 to ±80 °C) offer promising means to variety of device applications including flat panel TV displays, notebook, digital cameras, domestic devices. • Underlying principles for compounds featuring SLCs and insights from existing LCs can help in designing better SLCs that are yet to discovered by broadening the chemical space.

KEYWORDS:

• Room temperature liquid crystals
• single-component
• thermotropic
• device applications
• molecular design
• fragment-Based drug discovery

Acknowledgement

G. Shanker, and Bishwajit Paul acknowledges Faculty Recharge Programme, University Grants Commission (UGC-FRP), New Delhi, INDIA for their support. Also, GS thanks BANGALORE UNIVERSITY, Jnana Bharathi Campus, Bengaluru – 560056, for the financial support No:Dev:D2a:Financial Support:Dr.GS:Chem:2021-2022. GS and BP acknowledges the funding by Bangalore University (UO DEV:D2a:BU-RP:2020-21). Graphical Abstract folding funnel has been adopted from Ken A. Dill folding funnel hypothesis.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The work was supported by the Bangalore University [No:Dev:D2a:Financial Support:Dr.GS:Chem:2021-2022].