Liquid Crystal

Brief Synopsis

History

• Many scientists had already observed this phenomenon of liquid crystals prior to its "discovery", however the Austrian botanist Friedrich Reinitzer is more often then not given credit for its discovery.

Friedrich Reinitzer

• Friedrich Reinitzer

Description

• Cloudy liquid between solid and liquid phase.
  • Liquid Crystal flows and will take the shape of its container , however the cloudiness suggests it differs from liquids.

• Solids possess both positional order (molecules are constrained to occupy certain positions) and orientational order (the manner in which the molecules are oriented with respect to one another ?only nearest neighbor?). When a solid melts to a liquid both types of order are completely lost. However, when a solid melts to a liquid crystal only the positional order is completely lost.

• • Molecules are free to move about as in a liquid, however they on average spend more time pointing along the direction of orientation.

• Phase of matter "between" solid and liquid

• Thermotropic : Order Determined by temperature

• Lyotropic

Phases

• Nematic: No positional order; long-ranger orientation order

• Smectic: Positionally ordered along one direction

• Chiral

Applications

• Many common liquids are liquid crystals (i.e. soap)

Displays

• Televisions

Thermometer

• Mood Ring

Sources

Chien, Liquid Crystal Materials, Devices, and Applications IX

Collins, Liquid Crystals