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Physical Chemistry

Mesophase

Definition and meaning of Mesophase in chemistry.

Mesophase is an intermediate state of matter that exhibits physical properties existing between those of a conventional isotropic liquid and a highly ordered solid crystal.

In more detail

Substances occupying a mesophase, most notably liquid crystals, can physically flow much like ordinary liquids while still maintaining a significant degree of long-range molecular orientational order typical of solid crystals. This partially ordered internal structure means their physical properties, such as their refractive index and dielectric constant, are highly directionally dependent, a property known as anisotropy. Mesophases are usually formed by molecules possessing rigid, rod-like or disc-like geometries that spontaneously align themselves when placed under specific temperature ranges or when dissolved in certain solvents.

Key facts

FieldPhysical Chemistry
Common TypeLiquid crystals
Key PropertyAnisotropy
Example

The nematic liquid crystal phase widely utilized in LCD television screens is a mesophase where the rod-like molecules tend to orient in the same general direction while still moving freely past one another.

Frequently asked questions

Where are mesophases practically applied?

They are heavily utilized in modern display technologies, such as liquid crystal displays (LCDs), because their molecular alignment can be precisely controlled by external electric fields.

What causes a substance to enter a mesophase state?

Mesophases typically occur within specific transitional temperature ranges (thermotropic) or at certain solute concentrations in a solvent medium (lyotropic).

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