What is meant by lyotropic liquid crystals?
Lyotropic liquid crystals are formed in mixtures of amphiphiles (e.g., surfactants) and solvents, for example, detergents and water. Consequently, these phases are thermodynamically stable at defined temperatures, pressures, and concentrations. For example, at low curvatures lamellar phases are formed.
Is an example of lyotropic liquid crystal?
A mixture of soap and water is an everyday example of a lyotropic liquid crystal. Historically, the term was used to describe the common behavior of materials composed of amphiphilic molecules upon the addition of a solvent.
Which of the following is an example of lyotropic liquid crystal compound?
Soap is an everyday example of a lyotropic liquid crystal. The content of water or other solvent molecules changes the self-assembled structures. At very low amphiphile concentration, the molecules will be dispersed randomly without any ordering.
Is Kevlar a lyotropic?
For example, poly(p-phenylene terephthal- amide) (PPTA) which is the chemical structure of Kevlar® is a lyotropic LCP and exhibits outstanding mechanical properties, good thermal stability, and ex- cellent chemical resistance, but this polyamide fiber can only be spinned from its conc. H2SO4 solution.
What are the applications of liquid crystal?
Liquid crystals are everywhere. They are used in all kinds of display devices including computer monitors and laptop screens, TVs, clocks, visors, and navigation systems. Each pixel in a monitor is an assembly of liquid crystals controlled by its own electromagnetic field.
What is the difference between thermotropic and lyotropic liquid crystals?
Thermotropic and lyotropic are two types of liquid crystals. Thermotropic liquid crystals are crystals having a mesophase within a certain temperature range, while lyotropic liquid crystals are crystals forms that form from the dissolution of an amphiphilic mesogen in a suitable solvent.
What are thermotropic and lyotropic liquid crystals?
What is smectic liquid crystal?
A “liquid crystal”- (LC) is an organic compound whose molecules align themselves with an applied electric field. Smectic liquid crystals consist of flat layers of cigar-shaped molecules with their long axes oriented perpendicularly to the plane of the layer.
What is mesophase state?
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.
What are liquid crystals Why are they so called?
Polymers and Organic Compounds, Optical Properties of Below a certain critical temperature Tc, cholesterol shows an optical anisotropy (birefringence) like a crystal, despite the appearance of a cloudy fluid. Due to such an intermediate character, the name of “liquid crystals” was given to these novel materials.