Chirality of liquid crystal systems
Chirality is a fundamental concept in science, manifesting itself through the lack of mirror symmetry and is observed in the natural world as well as man-made materials. Chiral objects are objects which cannot be transformed into their mirror images by either rotation or translation. The easiest example to illustrate chirality in nature is the human hand. The right hand does not fit into a left-handed glove. Other well known examples include helically growing plants, snail shells and optically active crystals like quartz.
Molecules of opposite chiral handedness have very distinct differences. One of the most pronounced examples is found in oranges and lemons. The molecules that give both of their distinctive smells are actually of the same constitution, but differing in their chiral configuration, i.e. one handedness of the molecule is perceived as the smell of orange whereas the other handedness is perceived as the smell of lemon.
The identification and quantification of chirality is critically important in many areas of research, for example in drug manufacture where one chiral handedness of a molecule can be a life saving treatment whereas the other can lead to serious side effects. Liquid crystals are ideally suited materials to observe and study the effects of chirality due to their unique material properties; self-organisation, ferroelectricity in a fluid media and optical properties