|MadSci Network: Chemistry|
The answer should start with "What are crystals?":
Crystals are molecules ordered in a repetitive manner and on a lond range in all three dimentions. A good resource on crystals is Crystallography World Wide
Liquid crystals are molecules that are ordered in a two dimenssional but not in a perfect array, such would be membranes that would be cooled and other material of the type. All are connected by the fact that crystal, liquid crystal, and "cryst..." materials diffract X-ray and light. Liquid crystal polymers are best described in the plastic encyclopedia under Plastic Materials. I am sure you'll be able to find the proper uses for it there.
Try the links in the MadSci Library for more information on Chemistry.