Design of liquid crystals: from a nematogen to thiophene-based π-conjugated mesogens

Abstract

It is fundamentally important to study the relationships between structures and properties of liquid crystals. Professor G.W. Gray developed new rod-like nematic liquid crystals, 4-alkyl- and 4-alkoxy-4ʹ-cyanobiphenyls, which act as materials for stable informational liquid crystal displays. This molecule was invented based on his deep understanding of the relationships of chemical structure and physical properties of liquid crystals. After the discovery of nematogenic liquid crystals for display application, the advent of the molecular design and synthesis of liquid crystals has produced a variety of new family of functional liquid crystals. For example, as a new twist of rigid rod mesogens, oligothiophene rings have emerged recently. Due to their extended π-conjugated systems, oligothiophene-based liquid crystals exhibit various electronic and optical functions. In this review, we describe the impact of Professor Gray’s nematic liquid crystals as well as the structures and functions of oligothiophene-based liquid crystals.

Keywords:

• liquid crystal
• nematic
• mesogen
• supramolecular liquid crystal
• oligothiophene
• carrier transport
• liquid-crystalline semiconductor

Acknowledgements

The authors thank Masanari Nakayama for his contribution to the article.

Additional information

Funding

Partial financial support by Grant-in-Aid for Scientific Research [grant no. 22107003] on Innovative Areas of ‘Fusion Materials’ [grant no. 2206] from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) for T.K. is gratefully acknowledged. M.F. is thankful for partial financial support from a Grant-in-Aid for Scientific Research on Innovative Areas [New Polymeric Materials Based on Element-Blocks, grant no. 25102533] from the Ministry of Education, Culture, Sports, Science and Technology.