Liquid crystal structures contain the physical characteristics of liquids and solids.
Solids and liquids are two distinct classifications for nongaseous materials. These materials differ in their physical structures and how their molecules behave. Liquid crystals show characteristics of both solids and liquids, and can take on the properties of one or the other under certain conditions. Because of these unique characteristics, liquid crystals may provide new directions within modern technology developments.
History
The discovery of liquid crystals brought a new phase of matter into existence within the scientific world. According to Case Western Reserve University, the discovery came about through an experiment conducted in 1888 by Friedrich Reinitzer, an Austrian botanist. By heating a material called cholesteryl benzoate, Reinitzer observed that the material melted in two distinct phases. The first phase produced a cloudy liquid. Further heating caused the cloudy liquid to become clear. As a result, this new liquid-solid material--now known as liquid crystals--became known as a new form of matter.
Identification
Liquid crystals possess a unique physical makeup that incorporates the orderly molecular structure found in solids and the flexibility of structure found in liquids, according to Case Western Reserve University. This means their molecules naturally align themselves in a certain direction; however, the spacing between molecules creates a less dense structure. In effect, liquid crystal molecules appear as disconnected rodlike shapes. The molecules align themselves along a common axis, which creates an order, or stability like solids have.
Features
Because of their physical characteristics, liquid crystal structures are measured in three different orders, or dimensions--orientational order, bond orientational order and positional order--according to Case Western Reserve University. Orientational order measures the degree of alignment in terms of how much molecules point towards a certain axis, or in a certain direction. Bond orientational order measures how aligned each molecule is with the one alongside it. Positional order measures the degree of symmetry present throughout a liquid crystal structure.
Effects
The three structural orders contained inside liquid crystals represent a polymorphic state in which different phases of the material can be observed at the same time. As a result, it can be difficult to identify which state (crystal solid or liquid) a material is in. These phases appear as a liquid-solid continuum contained inside the material, according to Case Western Reserve University. Individual phases are described as subphases, or mesophases. When working with liquid crystal structures, scientists can manipulate subphases to produce different optical effects.
Uses
Liquid crystal materials are used to manufacture many different devices, some of which include watch faces, camcorder viewers and liquid crystal displays, according to the Science Encyclopedia. When exposed to light, the molecular structures contained inside liquid crystals can control how light rays pass through its crystalline material. This makes for variations in light intensity, color and where the light is directed. Researchers continue to develop new ways of controlling how molecules are arranged within structures to create new effects.
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