Crystalline Glassy

The thickness of the membrane phase can be either macroscopic ( thick )—membranes with a thickness greater than micrometres—or microscopic ( thin ), i.e. with thicknesses comparable to molecular dimensions (biological membranes and their models, bilayer lipid films). Thick membranes are crystalline, glassy or liquid, while thin membranes possess the properties of liquid crystals (fluid) or gels (crystalline). 

Contrary to a fluid in the gaseous state, a liquid has a surface, and is characterized by a surface tension. For water, the surface tension is 72 mN m" at 25°C [1,2]. Again, contrary to the fluid in the gaseous state, the volume of a liquid does not change appreciably under pressure it has a low compressibility and shares this property with matter in the solid (crystalline, glassy, or amorphous) state. For water, the compressibility is 0.452 (GPa)" at 25°C [1,2]. These are macroscopic, or bulk, properties that single out the liquid state from other states of aggregation of matter. 

Fig. 2 Schematic of dilation mechanism that is a prerequisite for the flow of solids. (A) In undisturbed state, grains are interlocked and behave much like an ordinary solid. (B) A granular bed dilates in response to applied shear, and can then flow. (C) In the flowing state, the bed can form distinct crystalline, glassy, fluid-like and gas-like phases. The crystalline phase is regular and ordered, the glassy phase is disordered but static, the fluid-like state flows but exhibits enduring contacts, and the gas-like state is characterized by rapid and brief interparticle contacts.

Conventional, Non-Liquid Crystalline Glassy Polymers Amorphous Poly(ethyleneterephthalate) [PET] (25) Poly(vinylchloride) [PVC] (26)... 

Polymers without flexible spacer groups. The DSC curves of t he polymer 3 indicated the existence of a liquid crystalline glassy state at room temperature. The polymer was found to be smectic. Two melting peaks were observed in the temperature range between 300 and 310 deg. C. These peaks are not as easily observed as in the case of the polymers discussed above, since the decomposition takes place in the same temperature range. The occurrence of exothermic peaks on cooling nevertheless indicates that reversible melting and crystallization processes take place. 

ELECTRICAL CONDUCTIVITY AND CHEMICAL BONDING IN CRYSTALLINE, GLASSY, AND LIQUID PHASES ... 

A qualitative quantum-mechanical treatment Is given of the mechanism of chemical bonding in crystalline, glassy, and liquid phases. It ls shown that the electrical properties of some substances can be explained on the basis of a relationship between the number of valence electrons, the number and kind of orbitals, and the overlap of the orbitals. 

High-resolution NMR in the solid state of matter has been developed fairly recently. Since this technique can detect the local structure of molecules via chemical shift and magnetic relaxation, it has been possible to obtain detailed information on chain conformation as well as chain dynamics of macromolecules not only in the crystalline state but also in the non-crystalline, glassy or rubbery state. This chapter gives a brief description of the basic principles of solid-state high-resolution NMR as well as its recent application to crystalline polymers. 

Figure 3.15 The time-dependence of cross-polarised signal intensity for crystalline, glassy and...

Most aspects have not been worked out for the thermodynamic properties and equilibria of systems of macromolecules in the crystalline, glassy, or solution form. There is much uncertainty about the use of dilute solution reference states for supercritical components, particularly in multisolute, multisolvent solutions. 

The following notation will be used to specify phases as a crystalline, glassy, or total system where V = total system, = amorphous system, and crystalline... 

The diffuse maximum at 26 = 18.7 and the shoulder at 20 26.3 on the WAXS diagram for the pristine PI (Figure 3a) evidenced its non-crystalline (glassy) state with small-scale order parameters of 0.47 nm and 0.34 nm (presumably, characteristic interchain and intrachain spacings, respectively). The essentially similar WAXS patterns for the PNC imply little influence of the organosilicon nanophase on the small-scale structure of PI. 

One of the few studies of transport in liquid crystalline glassy polymers has yielded some interesting results (140). The liquid and more ordered nematic morphologies characteristic of these highly rigid rod-like materials is compared in... 

By these various procedures block copolypeptides have been obtained with different combinations of crystalline, glassy or elastomeric, or hydrophilic and hydrophobic segments. In some cases, a sensitive group of the aminocarboxylic acid component has to be protected during the... 

We have to note at this point that despite the observed tendency of the polyesters studied to form the liquid-crystalline glassy state, no effort has been made so far, to study oriented samples of solid mcLCPs. As measurements of Davis and Ward have shown in the past, such studies may provide us with more significant information on different mechanisms governing the a- and j8-processes than can be extracted from measurements on unoriented materials. 

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