Ferroelectric liquid crystals applications

Ferroelectric Liquid Crystals Principles, Properties and Applications (PMade ph a Gordon and Breach)... 

Liquid crystals have found widespread application in optical display devices as well as in detection of temperature uniformity and impurities. These properties are related to the orientational order of molecules in the temperature region between and the melting point. The possible applications of ferroelectric liquid crystals are promising. Superconductors (type II) can be used to create high magnetic fields at low power the ability of type I superconductors to trap magnetic flux within the domains of the normal material may also have applications. 

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. 

Azo and azoxy series of ferroelectric liquid crystals Several of these were prepared one of them is shown in Figure 39. Unfortunately, these materials are not so stable and therefore useless for practical applications. 

Ferroelectric Liquid Crystals Designed for Electronic Nonlinear Optical Applications... 

More modern, much faster responding liquid crystalline displays use ferroelectric liquid crystals such as p decyloxybenzylidine-//-amine-2-methylbulylcinnamale, which can be switched between two stable states by application of an external field. Such properties may also be useful in optical data storage. 

The paper is organized as follows. Sect. 2 describes the general principles and recent results for the synthesis of cyclotriveratrylenes Sect. 3 describes some applications of these compounds to host-guest chemistry. This latter section is devoted principally to the cryptophanes, and to host molecules containing one CTV unit that have recently been described. Sec. 4 presents some prospective work in the field of material sciences, i.e., ferroelectric liquid crystals and organic three-dimensional charge transfer salts. 

Applications of cyclotriveratrylenes and cryptophanes to the design of materials for optoelectronics are still in the area of prospective research. We only mention here works dealing with ferroelectric liquid crystals and three-dimensional charge transfer salts. 

Calamitic metallomesogens forming a chiral smectic C phase (SmC ) are ferroelectric materials. Due to the low symmetry of this phase when the helix is unwound (C2) the molecular dipoles are aUgned within the layers of the SmC phase, giving rise to ferroelectric order in the layers. Because the SmC phase has a helical structure, there is no net macroscopic dipole moment for the bulk phase. However, it is possible to unwind the helix by application of an external electric field or by surface anchoring in thin cells. Under such conditions, a well-aligned film of the ferroelectric liquid crystal can exhibit a net polarisation, called the spontaneous polarisation (Ps). Ferroelectric liquid crystals are of interest for display applications because the macroscopic polarisation can be switched very fast by an... 

Goodby JW, Blinc R, Clark NA, Lagerwall ST, Osipov MA, Pikin SA, Sakurai T, Yoshino K, Zeks B (1991) Ferroelectric liquid crystals principles, properties, and applications, Gordon and Breach Science Publishers, Amsterdam... 

The twist grain boundary smectic phase was discovered serendipitously at Bell Laboratories in 1987. Its discovery followed the back-tracking of a number of decisions made concerning the development of ferroelectric liquid crystals for display device applications. 

During the 1980s the development of ferroelectric liquid crystals continued at Bell Laboratories, and the above property-structure correlations suggested to us that, for the development of smectic C and smectic materials which would be suitable for use in applications of ferroelectric displays, it would not be wise to investigate 1-methylalkyl-substituted systems because of the... 

Goodby JW (1994) In Bloor D, Brook RJ, Flemings MG, Mahajan S (eds) The Encyclopedia of Advanced Materials, Pergamon Press, Oxford, p 1325-1334 Goodby JW, Nishiyama 1, Slaney AJ, Booth CJ, Toyne KJ (1993) 14 37 Goodby JW, Blinc R, Clark NA, Lagerwall ST, Osipov MA, Pikin SA, Sakurai T, Yoshino K, Zeks B (1991) Ferroelectric Liquid Crystals Principles, Properties and Applications, Gordon and Breach, Philadelphia, p 99-123... 

It is our belief that block copolymers containing LC segments are materials with novel and unencountered properties which will offer great opportunities for developing high performance materials. Here we would like to give two examples. One example is a microphase stabilized ferroelectric liquid crystal (MSFLC) [109] for potential flat panel display applications, while the other is a material for stable, low surface energy [110] application. 

Ferroelectric liquid crystals (FLC) are of great interest due to their fast electro-optical response which is about 1,000 times faster than conventional twisted nematic cells [131]. The geometry used is called a surface stabilized FLC cell which utilizes a very thin gap (=2 pm) to unwind the FLC supramolecular pitch (=1-2 pm) since the bulk FLC materials do not show macroscopic polarization. This very thin gap, however, leads to difficulties in manufacturing large panels and very poor shock resistance. Researchers have proposed the concept of microphase stabilized FLC [79,109, 130] using FLC-coil diblock copolymers for electro-optical applications as shown in Fig. 15. This concept takes advantage of ferroelectric liquid crystallinity and block copolymer microphase separation since the block... 

Shelton and Shen, these harmonic generation studies are more novel than useful, in terms of possible practical applications. There has also been recent work on second harmonic generations in ferroelectric liquid crystals [13], but the observed conversion efficiency is still quite small compared to currently commercially available inorganic crystals. 

Much of this early effort dealt with modulator technology that is considered too slow (1-100 kilohertz) for high-speed applications such as optical interconnection and memory read/write. This includes modulators based on electrooptic effects in ferroelectric liquid crystals (ELCs) and in a ceramic containing lead, lanthanum, zinc, and titanium (PLZT). These electrooptic materials are bonded in some fashion to Si circuits to create hybrid SPAs. 

Komfield Ja, Wand M, Kurji Z. Ferroelectric liquid crystal (lie) polymers. US Patent Application 20100220279 2010. 

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