# What is anisotropic fluids

Anisotropy (Greek: "an (ti)" against / not "isos" equal, "tropos" rotation, direction) denotes the directional dependence of a property or a process. Anisotropy is the opposite of isotropy. The term is used in this sense in physics (e.g. radiation, magnetism, speed of propagation of earthquake waves), materials science, crystallography and mathematics applied to different properties of the systems under consideration.

### Examples

• The sun's radiation is isotropic, that of a laser is anisotropic.
• Directional arrangement of the crystallites in the metal (texture): this results in an anisotropy of the elastic and plastic deformability.
• The birefringence (optics) is based on an anisotropy of the refractive index.
• Liquid crystals are anisotropic liquids.
• An element x of a bilinear space (V, b) is called anisotropic if the equation b(x, x) = 0 does not apply.
• The elasticity of materials is generally anisotropic. This is described with the laws of elasticity. The most famous anisotropic elasticity laws are triclinic anisotropic, the orthotropic and the transversely isotropic Law of elasticity.
Examples: glass and carbon fiber reinforced plastics (GRP and CFRP) have a direction-dependent law of elasticity.
• Anisotropic etching of semiconductors enables a more precise control of the material removal. For this purpose, etchants are used that work preferentially in certain directions of the crystal lattice.
• All minerals are anisotropic.
• Fluorescence can be anisotropic to a certain extent, i.e. the emerging fluorescence radiation is not evenly distributed in terms of its plane of oscillation in these cases.