[Picture Credits: Oleg Lavrentovich from the Liquid Crystal Institute at Kent State University, for more pictures see here. Click to enlarge.]
A liquid crystal like the one pictured above is an anisotropic fluid formed by rod-like or disk-like molecules, typically some nanometers in length, that tend to be parallel to a common direction, similar to the ones used in an LCD screen. The properties of these crystals depend on the temperature, the above one is in the nematic phase, where the molecules have no positional order, but they have long-range orientational order. That is, though the molecules positions are randomly distributed as in a liquid, they all point in the same direction within each domain. This ordering is not perfect on sup domain scales. For more information on the arising defects, see e.g.
- "Topological point defects in nematic liquid crystals"
By M. Kleman and O. D. Lavrentovich
and if somebody can tell me why this paper belongs in a 'Philosophical Magazine' (Vol. 86, Nos. 25–26, 1–11 September 2006, 4117–4137), I'd really want to know. Oh well, I can give you my philosophy: defects are interesting, and beauty is not just in simplicity.
TAGS: PHYSICS, LIQUID CRYSTALS