How liquid crystals are formed?
Liquid crystals that are formed by temperature change (“partial melting” of the solid phase) are called thermotropic liquid crystals. Lyotropic liquid crystals are formed due to changes in the concentration of surfactants in a solvent.
What are the phases of liquid crystal?
Next, the primary phases of liquid crystals are described: the isotropic, nematic, cholesteric (or helical), and smectic phases.
How is liquid crystal phase determined?
The existence of liquid crystal phase can be detected by using polarized optical microscopy, since liquid crystal phase exhibits its unique texture under microscopy. The contrasting areas in the texture correspond to domains where LCs are oriented towards different directions.
What is nematic phase of liquid crystal?
The nematic liquid crystal phase is characterized by molecules that have no positional order but tend to point in the same direction (along the director). In the following diagram, notice that the molecules point vertically but are arranged with no particular order.
Do liquid crystals flow?
Liquid crystals (LCs) are a state of matter which has properties between those of conventional liquids and those of solid crystals. For instance, a liquid crystal may flow like a liquid, but its molecules may be oriented in a crystal-like way.
What are liquid crystals in chemistry?
Liquid crystal (LC) is an intermediate state between crystal and liquid showing the properties of both. For example, liquid crystal may flow like a liquid but its molecules may have a specific crystal-like orientation.
What are liquid crystals in physics?
liquid crystal, substance that blends the structures and properties of the normally disparate liquid and crystalline solid states. Liquids can flow, for example, while solids cannot, and crystalline solids possess special symmetry properties that liquids lack.
What are liquid crystals chemistry?
What do you understand by liquid crystals?
A liquid crystal is a state of matter between liquid and solid (a “mesophase”). They change shape like a fluid but have the molecular alignment characteristics of a solid crystal.
What is nematic and smectic?
The key difference between nematic smectic and cholesteric liquid crystals is that nematic liquid crystals have no ordered structure of molecules, and smectic liquid crystals have a layered molecular structure, whereas cholesteric liquid crystals have molecules in a twisted and chiral arrangement.
What is the nematic phase?
The nematic phase is characterized by one-dimensional orientational order of the molecules by virtue of correlations of the long molecular axes, although the orientational order is not polar. There is no translational order within the nematic phase.
Why do liquid crystals form?
Ordinary solids melt into ordinary liquids as the temperature increases—e.g., ice melts into liquid water. Some solids actually melt twice or more as temperature rises. Between the crystalline solid at low temperatures and the ordinary liquid state at high temperatures lies an intermediate state, the liquid crystal.