Optical monitoring of gases with cholesteric liquid crystals

Cholesteric liquid crystals doped with reactive chiral compounds are used for describing a new approach to optical monitors for gases. The method is based on cholesteric pitch length changes caused by a change in helical twisting power and it is used for monitoring carbon dioxide via reversible carbamate formation and for oxygen using the irreversible oxidation of a chiral dithiol to a disulfide.