Liquid crystalline mixtures

Several liquid-crystalline mixtures have been employed In this work. They and several of their physical characteristics are collected In Table I. As expected, the bulky BN molecules disturb mesophase order causing transition temperatures to be lowered. Monotropic c+K transitions are approximate since they depend upon the rate of cooling and other factors. 

For a discussion of the principles underlying the calculation of phase diagrams for liquid crystalline mixtures see M. Domon and J. Billard, in Proceedings of the International Liquid Crystals Conference, Bangalore, December 1973, Pramana Supplement I, p. 131. 

The present contribution is focussed on the relation between chain packing and mesophase structure in liquid crystalline mixtures of phospholipids with alkyl polyfoxy-ethylene) surfactants. These compounds are frequently... 

Fig. 2 Deuterium ordering profiles of the sn-1 and sn-2 chains of DMPC-dj4 in lamellar (left panel) and hexagonal (right panel) liquid crystalline mixtures with Ci2Es. Water content 50 wt%. Temperature, 30 °C. The molar ratios DMPC-d54,/Ci2E8 are given in the insets. The profile for pure DMPC-dj4 is included for comparison...

Table 1 Average length , area , interfacial area , and thermal expansion coefficient a, of the sn-1 chain of DMPC-ds4 in CizEg/DMPC-ds4 liquid-crystalline mixtures (water content 50 wt%)...

Liquid Crystals I 1.3 Physical Properties of Some Liquid Crystalline Mixtures 975... 

Part 5 covers special structures such as liquid crystals, solid surfaces and mesoscopic and nanostructured materials. The chapter on liquid crystals covers physical properties of the most common liquid crystalline substances as well as some liquid crystalline mixtures. Data compiled in the chapter on solid surfaces refer to atomically clean and well characterized surfaces. The values reported are mainly averages from different authors where reference to the original papers is made. In the chapter on nanostructured materials emphasis is placed on size and confinement effects. The properties associated with electronic confinement are addressed and particular attention is drawn to semiconductor-doped matrices. The two main applications of nanostructured magnetic materials, spintronics and ultrahigh-density data storage media, are also treated. 

Unfortunately, most of the liquid crystalline mixtures are far from being ideal solutions. Intermolecular interactions result in the deviation of experimental data from theoretical data. Moreover, new phases can occur in mixtures of nematogens. For example, a binary mixture may be more preferable for the formation of the smectic A phase, due to a specific packing of different-type molecules with each other [35]. In addition, many mixtures display a so-called reentrant polymorphism. 

In liquid crystalline mixtures the following additivity law for the effective value of dielectric anisotropy is valid ... 

In 1995, Inui etal. reported that the liquid crystalline mixture (I) shown below gives switching without hysteresis or threshold properties [29],... 

Preparation and control of the size and structure of fuel cell catalysts in the nanosize range using templates synthesis methods has attracted some attention. The best known synthesis method is probably the deposition of metal films from lyotropic liquid crystalline mixtures developed to by Phil Bartlett s group [71-73]. They have used the method to deposit films of Pt, Pt/Ru alloys, and other metals. 

The 4- and 5-fluorooxazole derivatives have also the potential technical application. Thus, it has been found that some lluorinated oxazoles, even when admixed in small amount, have a favorable effect on the properties of liquid-crystalline mixtures [76]. 

Wingen R, Hornung B, Ogawea A, Schmidt W (2001) Fluorinated azoles, and their use in liquid-crystalline mixtures. US Patent 6,231,786, 15 May 2001... 

Diffusivities of binary, ternary and multi-component liquid crystalline mixtures, e.g. of soap (potassium laurate (PL), water [25, 58], and lipid (dipalmitoylphosphatidylcho-line (DPPC) [25, 59] systems in lamellar, hexagonal, cubic, nematic and micellar mesophases [25,60,61] have been studied extensively by pulsed-field-gradient NMR [25] and optical techniques [62], partly because of their intimate relation to the structure and dynamical performance of biological membranes [18]. The main distinction from thermotropic phases is that for layered structures a noticeable diffusion occurs only within the layers (i.e. lateral, frequently written as Dl, but in our notation DjJ, whereas it is negligibly small and difficult to detect across the layers [60-62] (transverse migration, for bilayers denoted by flip-flop ) so the mobility is essentially two dimensional, and the anisotropy ratio is so great that it is seldom specified explicit-... 

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