Weak elastic properties

Chandrasekhar, 1977). This cooperative behavior results in weak elastic properties. Then, the application of an electric field can easily change the molecular orientation, which is initially fixed by the mechanical boundary conditions. The concomitant changes in the optical properties form the basis of liquid crystal displays (LCD). 

For more details about the sensory properties of the pectin preparations additional sizes such as thixotropy and viscosity have to be referred to (see figure 6). Fruit preparations with apple pectin Classic AY 901 have a relatively high yield point after shearing, a small thixotropic area, and a relatively high viscosity. This supports the statement, that their texture is weakly elastic and highly reversible. The apple pectin Classic AY 905 gives products with a sufficiently high yield point at 35 % soluble solids and a pronounced area of thixotropy. 

The cis-polyisoprene molecule consists of various chains held together by weak van der Waals interactions and has a coiled structure. Thus, it can be stretched like a spring and exhibits elastic properties. 

Successful assembly requires matching features of the template, meaning that wavelength and height have to be of the same dimensions. Additionally, adhesion of particles and surface must be avoided by weak repulsive forces. In this context, polyelectrolyte multilayer-wrinkles are particularly useful, as the wettability of the multilayer is determined by the part of the layer adjacent to the film/solution or film/air interface respectively, while the elastic properties are determined by the total film [84], Thus, elastic constants can be adjusted largely independent from wettability properties. 

Figure 3. Ratio of the mean square root displacements derivatives along directions of weak and strong coupling, calculated in the model of a highly anisotropic layered crystal. Its anisotropy of interatomic interaction and elastic properties correspond to those of NbSe2. The pronounced maximum on this curve corresponds to a minimum on the temperature dependence of the thermal expansion along the layers.

The properties of the surplus segment probability p and the effective constraint coordination number z are less well established. It seems possible that p will dep d on polymer species to some extent, since loop projection may be easier for a more locally flexible chain. Weak dependences on concentration and temf rature are likely for the same reason. On the other hand, z characterizes the topology on a fairly large scale and therefore may be virtually a universal constant. Diese however are only some speculations. Values of p and z can be established by various experiments, p from the elastic properties of networks and also from the relaxation of star polymers, z from relative relaxation rates of linear and star molecules in liquids and networks and also from measurements of diffusion rates of stars in linear chain liquids. The adequacy of the... 

Figure 8 summarizes the properties of the gels produced by heating 1% gum solutions to 90°C for 10 minutes in the presence of cations, followed by cooling. The native PS-60 forms weak elastic gels which have the same melting and setting temperatures with no hysteresis. 

Fibrous networks with permanent interconnections will effectively entrap and immobilize liquid in the meshes, and possess both the elastic properties of ideal solids and the viscosity properties of Newtonian liquids. Consequently, self-supporting supramolecular materials will be obtained [8-10,15-21]. til contrast, systems consisting of nonpermanent/or transient interconnecting (or entangled) fibers or needles can only form weak and viscous paste at low concentrations [6,7]. 

Turbidity is a distinctive feature of the nematic phase. This is a consequence of large birefringence and weak elasticity. These properties favor low power devices. The optical path length in a nematic device is limited 100 jam by turbidity. The following expression for the optical scattering cross section can be written in the limit Aw/n... 

Remarkable elastic properties are observed in mixtures of weak and strong polar compounds [46-49]. The situation is simple for the concentration dependences of Kn and K221 which obeyed a simple additivity law [46]... 

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