Design and synthesis of ferroelectric and antiferroelectric liquid crystals


In cooperation with the Liquid Crystals Group of the Department of Dielectrics we work on the molecular design and synthetic methods leading to new ferroelectric and antiferroelectric materials with self-organising (liquid crystalline) nature.

We mainly focus on materials of rod-like and bent-core molecular shape. Typically, we chemically modify the molecular structure by introduction of lateral substituents like methyl- and methoxy- group or halogens. Such substituents influence the geometry and electronic distribution in the molecule resulting in changes of self-organising properties of molecules and as a result, the change in particular bulk physical properties of the final material.

In molecular design of our new mesogens and chiral additives for LC mixtures we focus on utilisation of natural molecules as a source of chirality. Except for bent-core mesogens the chirality is the only way to induce ferroelectric and antiferroelectric behaviour of liquid crystalline materials.  Natural chiral compounds are not only cheap and readily available alternative to synthetic substances, but their incorporation in the molecular structure usually improves the biodegradability and thus lowers the potential negative ecological impact of these compounds. For the study of self-organisation and molecular dynamics in liquid crystalline state by 2H-NMR, we also synthesise selectively deuterated liquid crystals. 

Example of molecular structure of material based on lactic acid showing ferroelectric SmC* phase and molecular organisation in the surface stabilised form of this mesophase
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