Development and applications of cholesteric liquid crystals

The development and realisation of applications utilising the cholesteric or chiral nematic phase have benefited from the materials research work carried out by George Gray and his colleagues. His work on cholesteric materials started in the 1950s with the synthesis of cholesteryl esters and the observation in them of an unusual blue fog phase which he later studied in more detail. He went on to identify the molecular features that give rise to the characteristic cholesteric helical structure and the role of molecular structure and chirality on the properties of the cholesteric phase. This pioneering work paved the way for a wide range of applications of which a few are exemplified.