What are Liquid crystals ? Its History & Discovery
Any of various liquids in which molecules are regularly arrayed like a solid crystal along one or two dimensions, but are free in the other dimensions as with typical liquids. Liquid crystals often display unusual and often manipulable optical properties such as anisotropic scattering. They can be divided into two classes, Thermo tropic(nematic, chiral nematic, and smectic.) and Lyotropic. Transitions to thermotropic phases are initiated by changes in temperature, while those to lyotropic phases can also be initiated by changes in concentration.
The Discovery, March 1, 1888 Friedrich Reinitzer, a plant physiologist at the Charles University, in Prague, notices that the plant derivative cholesteryl benzoate has two melting points. New Compounds Identified, 1889 — 1908 European scientists identify more than 200 compounds exhibiting liquid crystal behavior, but no commercial uses are found. Flowing Crystals Get Their Name , January 1, 1889 Otto Lehmann, a physical chemist working in Aachen, Germany, publishes an article on what he terms fliessende Krystalle, or “flowing crystals,” noting that within a certain temperature range cholesteryl benzoate pours like a liquid but refracts polarized light like a crystalline solid. Three Classes of Crystal, November 1, 1922 French crystallographer Georges Friedel publishes an article in which he divides liquid crystals into three categories based on their molecular organization: nematic, smectic, and cholesteric. Recent Developments
Nematic Liquid Crystal Confined in Electrochemically Etched Porous Silicon: Optical Characterization and Applications in Photonics. Liquid Crystals into Planar Photonic Crystals .
Manipulating Nematic Liquid Crystals-based Magnetophotonic Crystals. A New Method of Generating Atmospheric Turbulence with a Liquid Crystal Spatial Light Modulator. Three Dimensional Temperature Distribution Analysis of...
Please join StudyMode to read the full document