Ferroelectric liquid crystalline polymers applications

Kiefer, R., Application of ferroelectric liquid crystalline polymers, in Ferroelectric Polymers Chemistry, Physics, and Applications (H. S. Nalwa, ed.), Marcel Dekker, New York, 1995, pp. 815-880. 

The surface-stabilized ferroelectric liquid crystals in the smectic C (SmC ) phase are among the most interesting types of liquid-crystalline systems because of their potential applications in high-resolution flat panel displays and fast electro-optical devices [73-76]. Within this class of compounds, ferroelectric liquid-crystalline polymers (FLCPs) have gained theoretical and practical interest as systems which combine the properties of polymers and ferroelectric liquid crystals. This combination is achieved by attaching the ferroelectric mesogen to a main chain via a flexible spacer... 

Application of the concepts obtained in the study of PVDF and its copolymers has been made for other types of novel polymers with similar polar chemical structure. For example, poly(vinylidene cyanide) (PVDCN) and its copolymer with vinyl n-fatty acid ester have ciMmical structures close to that of PVDF F atoms arc displaced by CN groups. These polymers are also attracting attention because of their characteristic electric properties. Odd-numbered members of nylon (nylon 7, nylon 11, etc.) and ferroelectric liquid-crystalline polymers (FLCP) are also the candidates for ferroelectric polymers. These substances are still new. and their structural study has not yet been developed extensively compared with the study of PVDF and its copolymers. 

Ferroelectric Liquid Crystalline Polymers Properties and Applications... 

Perhaps one of the most important applications of chiral induction is in the area of liquid crystals. Upon addition of a wide range of appropriate chiral compounds, the achiral nematic, smectic C, and discotic phases are converted into the chiral cholesteric (or twisted nematic), the ferroelectric smectic C and the chiral discotic phases. As a first example, we take the induction of chirality in the columns of aromatic chromophores present in some liquid-crystalline polymers. " The polymers, achiral polyesters incorporating triphenylene moieties, display discotic mesophases, which upon doping with chiral electron acceptors based on tetranitro-9-fluorene, form chiral discotic phases in which the chirality is determined by the dopant. These conclusions were reached on the basis of CD spectra in which strong Cotton effects were observed. Interestingly, the chiral dopants were unable to dramatically influence the chiral winding of triphenylene polymers that already incorporated ste-reogenic centers. 

Suda K, Akagi K (2008) Electro-optical behavior of ferroelectric liquid crystalline polyphenylene derivatives. J Polym Sci A Polym Chem 46 3591-3610 Sun HY, Chen HX, Zheng MS (2005) Synthesis, properties and applications of the polyphenylene. HuaXue Tong Bao 7 515-521... 

Ferroelectric liquid crystals (FLC) have attracted attention because of their high speed response and memory effect (7-5). The characteristics of fast response and memory effect make them suitable in electro-optical device applications, such as display, light valve and memory devices. Ferroelectric side chain liquid crystalline polymers (FLCPs) exhibit desirable mechanical properties of polymers and electro-optical properties of low molecular weight FLC, which have been investigated extensively Corresponding author. 

It can be safely predicted that applications of liquid crystals will expand in the future to more and more sophisticated areas of electronics. Potential applications of ferroelectric liquid crystals (e.g. fast shutters, complex multiplexed displays) are particularly exciting. The only LC that can show ferroelectric property is the chiral smectic C. Viable ferroelectric displays have however not yet materialized. Antifer-roelectric phases may also have good potential in display applications. Supertwisted nematic displays of twist artgles of around 240° and materials with low viscosity which respond relatively fast, have found considerable application. Another development is the polymer dispersed liquid crystal display in which small nematic droplets ( 2 gm in diameter) are formed in a polymer matrix. Liquid crystalline elastomers with novel physical properties would have many applications. 

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