The chemistry of liquid crystals

The nature of the liquid crystal phases formed by different compounds and the thermal and other physical characteristics of these phases are strongly affected by the stereochemistry and structure of the molecules. Precise structure-property correlations of an embracing nature cannot yet be quantified, but even a qualitative understanding of such relations is desirable from many standpoints, including that of the achievement of still better liquid crystal materials for the ever widening range of applications that is emerging for these ordered but fluid systems. By means of a range of selected examples, an attempt is made to illustrate not only those areas where generalizations seem possible, but also others wherein the properties of the materials are much more difficult to understand, to such an extent that doubt must be cast on at least some theoretical concepts of the liquid crystal state.