Cholesteric liquid crystals - The Storage Model
Cholesteric liquid crystals are distorted forms of the nematic phase. The spiral arrangement of the molecules in this mesophase is responsible for its unique optical properties, selective reflection of circularly-polarized light and a rotatory power a thousand times greater than that of an ordinary optically active substance. Cholesterics also exhibit dynamical convective instabilities which give rise to the Storage Mode or Memory Effect. Two models - the Heilmeier Model based on the principle of field-induced emulsion and the Carr-Helfrich Model which assumes charge accumulation, will be studied and compared. Recent researches on the Storage Model, i.e., lifetime measurements, IR laser beam, approach, applications in microencapsulation and xerographic techniques will also be discussed.