What are liquid crystals explain its types with applications?
There are three types of liquid crystal: nematic, smectic and cholesteric. In the liquid crystalline phase, the vector about which the molecules are preferentially oriented, n, is known as the “director”. The long axes of the molecules will tend to align in this direction.
What are inorganic liquid crystals?
Organic liquid crystals and lyotropic liquid-crystalline inorganic fine particles. Liquid crystal (LC) is one of the most representative functional materials, which shows both fluidity and crystallinity. Material showing liquid crystalline property induced by the changes of the temperatures is called as thermotropic LC …
What is Mesophase in liquid crystal?
The term mesophase is used to describe the “subphases” of liquid crystal materials. Mesophases are formed by changing the amount of order in the sample, either by imposing order in only one or two dimensions, or by allowing the molecules to have a degree of translational motion.
What are the applications of liquid crystal in pharmaceutical industry?
Liquid crystal formulations have been used in cosmetics and pharmaceutical controlled release dosage forms. These formulations get enhanced penetration of biologically active materials like vitamin A) through the skin.
What is meant by mesophase?
In chemistry and chemical physics, a mesophase is a state of matter intermediate between liquid and solid. Gelatin is a common example of a partially ordered structure in a mesophase. Further, biological structures such as the lipid bilayers of cell membranes are examples of mesophases.
How do liquid crystals bend light?
If you ‘cross’ two polarisers (i.e. arrange them at 90 degrees to each other) then light does not pass through. This is the basis of the LCD, but between the cross polars the liquid crystals are arranged with a ‘twist’. This twist allows light to pass through.
What are Liquid Crystal Display explain their working with the help of neat diagram?
The liquid crystal display screen works on the principle of blocking light rather than emitting light. LCDs require a backlight as they do not emit light them. We always use devices which are made up of LCD’s displays which are replacing the use of cathode ray tube.
Why liquid crystals are used in controlled drug delivery system?
Liquid crystals have been recently studied as novel drug delivery system. The reason behind this is their similarity to colloidal systems in living organisms. They have proven to be advantageous over Traditional, Dermal, Parentral and Oral Dosage forms.
What are the properties of liquid crystals?
What are Liquid Crystals? Liquid crystal materials generally have several common characteristics. Among these are a rod-like molecular structure, rigidness of the long axis, and strong dipoles and/or easily polarizable substituents.
What is thermotropic liquid crystal?
Thermotropic liquid crystals (LC) are anisotropic liquids that possess a mesophase (a phase with crystal and liquid properties) within a certain temperature range. In a spectrometer magnet, LC molecules tend to orient to a common direction which defines the director of the liquid crystal.
What are bent-core molecules?
Bent-core (BC) molecules became an attractive liquid crystal class due to their potential use in smart displays and photonic devices.
What is the orientation of the bent core molecules?
The bent-core molecules are preferentially packed into bent directions and parallelly aligned to each layer.
Is naphthalene the central core of bent-core benzene compounds?
The presence of 2,7-disubstituted naphthalene as central core in bent-core compounds mainly destabilized the mesophases, compared with 1,3-disubstituted benzene derivatives.
What are the properties of biaxial crystals?
The properties of biaxial liquid crystals can be influenced by the substituents of central nucleus, lateral arms, and terminal units. The central aromatic core generally consists of naphthalene, benzene, and heterocyclic units.