Liquid crystals have the unusual property of responding to changes in temperature with striking changes in colour. Since these changes can also take place in the range of room temperatures, the crystals have potential value for artists. These organic materials seem to possess two sharp and distinct melting points between which they are said to be in the ‘liquid crystal’ state. Liquid crystals are classified as nematic, smectic and cholesteric, depending on their molecular structure. Cholesteric liquid crystals, which are composed of cholesterol ester derivatives with eccentric molecular structures, are the most interesting. They respond not only to variations of temperature but also to mechanical stress, electromagnetic radiation and chemical environment with chamelion-like colour changes. The combination of colours exhibited by a particular liquid crystal depends on its chemical composition, on the magnitude of the applied stress and on the relative angles of illumination and viewing. A recent process, called encapsulation, permits liquid crystals to be produced in a convenient form which is durable and easy to use. The techniques of application of the liquid crystals as surface coatings are presented and current uses of these materials are outlined. Possible future developments are also mentioned but the question of how liquid crystals may be used by artists is left open.
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