Why Have Only One Color When You Can Have Them All?
The pigments consist of an organic polymer network comprising a so-called liquid crystalline phase. Liquid crystals (LCs) are molecules that enter a state of matter showing characteristics of both isotropic melt and the ordered crystal when heated above their melting point. In the LC state, the molecules are moving like a liquid but still exhibit degrees of molecular order normally only found in solid crystals. Consequently, some physical properties are angle dependent in the liquid crystalline state, including refractive index, thus adding unique optical properties to the system.
Several kinds of LC phase structures are known. The most common one, the nematic LC phase, is observed in the case of markedly stiff, cigar-shaped molecules. In their liquid crystalline state, the molecules are oriented along a director.