Do liquid crystals have long range order?
Do liquid crystals have long range order?
The key characteristic of liquid crystals is that they exhibit long-range order in at least orientation, while largely maintaining the molecular mobility of isotropic liquids (at least for the nematic phase which has no long-range positional order and where the molecules thus have very large translational freedom).
What are the chemical properties of 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 are liquid crystals mention their classification?
Liquid crystals are classified in many ways, molecules within the mesophases (mesogens) can be calamitic (rod-like), discotic (disc-like), amphiphilic, nonamphiphilic, metal containing, non-metal containing and low molecular weight or polymeric. Liquid crystals either show thermotropic behaviour or lyotropic behaviour.
What is order parameter of liquid crystal?
For a perfect crystal, the order parameter evaluates to one. Typical values for the order parameter of a liquid crystal range between 0.3 and 0.9, with the exact value a function of temperature, as a result of kinetic molecular motion.
How do you characterize liquid crystal?
The main factors to be considered for describing liquid crystalline structure involve their positional, orientational and bond orientational or- der. By considering these parameters, one can iden- tify the proper phase as well as the interactions between molecules of liquid crystals.
How is liquid crystal phase determined?
If the temperature is too low, thermal motion is hard to perform, so the material will become crystal phase. The existence of liquid crystal phase can be detected by using polarized optical microscopy, since liquid crystal phase exhibits its unique texture under microscopy.
What is a liquid crystal phase?
A liquid crystal is a thermodynamic stable phase characterized by anisotropy of properties Without the existence of a three-dimensional crystal lattice, generally lying in the temperature Range between the solid and isotropic liquid phase, hence the term mesophase.
