Mesophase current research

Beginning with a discussion of the necessary basic physics and chemistry, the book proceeds to a description of the main topics of current research in this field. The Langmuir-Blodgett technique, self-assembly, and methods of film deposition exploiting the ordered structure of mesophases are discussed. Separate chapters are devoted to the properties and computer modelling of both liquid crystals and films at the air/water interface. Order in biomemebranes is also discussed. 

The primary aim is to introduce the current concepts used to interpret the properties of homogeneous, optically transparent, self-assembling aqueous solutions of small molecule surfactants that form into association colloids composed of charged or uncharged surfactants into micelles, miaoemul-sions, vesicles, or other mesophases. Pseudophase models are used to interpret chemical reactivity in surfactant solutions. Large surface-active molecules such as proteins, starches, and polymers are not considered. Much of the information is on surfactant solutions at room temperature and atmospheric pressure because most of the important properties, concepts, and unanswered questions can be developed at ambient conditions. Effects of additives such as salts, alcohols, and oils, and temperature are introduced briefly. Many introductory books include substantial sections on surfactant self-assembly. " Current research on a variety of topics is periodically reviewed in Current Opinion in Colloid and Interface Science. 

The rapid rise in computer speed over recent years has led to atom-based simulations of liquid crystals becoming an important new area of research. Molecular mechanics and Monte Carlo studies of isolated liquid crystal molecules are now routine. However, care must be taken to model properly the influence of a nematic mean field if information about molecular structure in a mesophase is required. The current state-of-the-art consists of studies of (in the order of) 100 molecules in the bulk, in contact with a surface, or in a bilayer in contact with a solvent. Current simulation times can extend to around 10 ns and are sufficient to observe the growth of mesophases from an isotropic liquid. The results from a number of studies look very promising, and a wealth of structural and dynamic data now exists for bulk phases, monolayers and bilayers. Continued development of force fields for liquid crystals will be particularly important in the next few years, and particular emphasis must be placed on the development of all-atom force fields that are able to reproduce liquid phase densities for small molecules. Without these it will be difficult to obtain accurate phase transition temperatures. It will also be necessary to extend atomistic models to several thousand molecules to remove major system size effects which are present in all current work. This will be greatly facilitated by modern parallel simulation methods that allow molecular dynamics simulations to be carried out in parallel on multi-processor systems [115]. 

The complexity of formation of mesophase must not be underestimated. With the exception of a few model compounds, it is the industrial pitch which is the source of mesophase. Such materials contain thousands of reactive molecules and there is an interdependence in the carbonization system which currently is known to us but not analyzed in depth. This is an area for further research. Formation of mesophase is further complicated because it involves chemistry within a fluid/plastic system of increasing viscosity. And in the delayed coker, volatile release and liquid turbulence are yet additional factors in influencing final structure in mesophase. 

Current Mesophase Research. With a view to production of carbon fibres and of graphite/carbon artifacts of specialized use, the research programmes appear to be orientated towards -... 

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