Liquid crystal plastic

This calculation, which holds true for most metals, is generally applicable to TPs. However, the designer is to be familiar with the inherently nonlinear, anisotropic nature of most plastics, particularly the fiber-reinforced and liquid crystal plastics (Chapter 6). 

Electro-optic The liquid crystal plastics exhibit some of the properties of crystalline solids and still flow easily as liquids (Chapter 6). One group of these materials is based on low polymers with strong field interacting side chains. Using these materials, there has developed a field of electro-optic devices whose characteristics can be changed sharply by the application of an electric field. 

Because all glasses are clearly solids, the names liquid crystal glass or plastic crystal glass are awkward. The terms LC-, PC- and CD-glass thus stand for glass obtained by quenching a liquid crystal, plastic crystal, or condis crystal, respectively. 

The thermotropic mesophases are well enough understood to propose a subdivision into six types. Depending on the type of disorder, they are called liquid crystals, plastic crystals or condis crystals (positional and if applicable conformational disorder, orientational disorder, and conformational disorder, respectively). For the corresponding glasses, which represent the frozen-in mesophases, the names LC-, PC-, and CD-glasses are proposed (Fig. 2). For macromolecules not only equilibrium... 

The differences between the three mesophases, liquid crystal, plastic crystal and condis crystal could be clarified and, although difficult to classify, intermediate cases remain. If the molecule permits dynamic conformational disorder in the liquid phase, the same is usually also possible in a similar temperature range in the liquid-crystalline and plastic-crystalline phases. 

Liquid crystals, plastic crystals and condis crystals... 

To begin with, and contrary to a still widely held belief, the words liquid-crystalline and mesomorphic are not synonymous. The term mesomorphic phases was introduced by Friedel in 1922 [1] it is now often abbreviated to meso-phases. He defined them as phases with microscopic structures between solids and ordinary isotropic liquids. Not much happened in this area until 1955 when Kast [2] tried to characterize such phases in terms of lateral, longitudinal, and steric disorder. The next step occurred in 1984 when Wunderlich and Grebowicz [3] defined condis crystals for the first time. Following them [3,4] we now distinguish three kinds of mesophases liquid crystals, plastic crystals, and condis crystals. 

G. W. Gray and P. A. Winsor, eds.. Liquid Crystals Plastics Crystals, Vol. 1, John Wiley Sons, Inc. New York, 1974. 

The internal molecular arrangement of a solid in general can be projected as a continuum between well-ordered crystalline state and completely disordered amorphous state (Fig. 1.2). A crystalline material is depicted as having three-dimensional long-range symmetry operators over a domain of at least 1000 individual molecules. A mesophase material (liquid crystals, plastic crystals) is depicted as having intermediate symmetry operators, and an amorphous state has no symmetry operators (Klug and Alexander 1974). 

Changes in relaxation rates also arise from changes in the electric field gradient in the vicinity of the nucleus. Such variations can be induced by intermolecular aggregation, solvation, or binding of added species (e.g., metal ions to basic binding sites). Phase changes (isotropic liquid crystal > plastic crystal) can also be probed via relaxation and line-shape studies (8). 

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