Ferroelectricity in liquid crystals—materials, properties and applications

Abstract

Molecular chirality confers the necessary reduced symmetry to tilted smectic liquid crystals and disordered crystals to generate ferroelectric properties. By definition, ferroelectrics are materials that possess a spontaneous polarisation in the absence of an external field, and on the application of an electric field, the polarisation can be reoriented. Combine the fluidity of liquid crystals with ferroelectric properties and a fast-switching electro-optic device is possible. However, the road was very rocky in developing ferroelectric technology into commercially viable devices, despite the many advantages over the existing nematic-based devices. Indeed, research and development is on-going to enable ferroelectric technology to be more widely adopted. This review introduces the phenomenon of ferroelectric liquid crystals and charts the development of the technology to commercially viable devices, with a specific focus on the development of suitable materials in terms of design, synthesis and properties.

Keywords:

• liquid crystals
• ferroelectric
• synthesis
• chirality
• smectic C

Acknowledgements

I thank all colleagues and collaborators who I have had the pleasure of working with over many years of research, in particular Professor John Goodby FRS and Dr Rob Lewis. Most importantly, I am most grateful to my mentor, supervisor, colleague and very good friend the late Professor Ken Toyne for his unstinting support, guidance and advice for over 25 years.