Unusual Multilayers

Characterization of these unusual multilayer samples was accomplished using small angle X ray diffraction, electro diffraction and Fourier transform infrared spectroscopy. ... 

Unusual Multilayers In previous work we demonstrated that multilayers of poly(vinyl stearate) which normally occur as X layers (head to tail) can be prepare gWith the side chains packed in Y layers (head-head-tail-tail)L By the technique described in the experimental section we have obtained an X structure for multilayers of the polymerized cadmium salt of octadecylacrylic acid, a g material that normally forms Y structures. As with vinyl stearate the turn around of the cadmium salt of octadecylacrylic acrylic acid monomer layers during the up trip through the gas-water interface is precluded by polymerizing each layer underneath the watergSurface. This has been verified by changes in the infrared spectrum and by x-ray diffraction measurements, which show that the repeat corresponds to 2SA not 56A as would be expected for head-head-tail-tall layers. 

However, it was soon realized that the resulting anchored complexes exhibited unusual catalytic properties, and that the grafted catalysts could be obtained with controlled dispersion (isolated species, monolayers, multilayers). It appears that the nature of the catalysts obtained depends on many parameters such as the nature of the precursor. 

C4 has resulted in a drastic reduction in the extent of multilayer adsoiption. The reason for this unusual physisorpdon behaviour is that the molecules in the localized monolayer are oriented to allow directional hydrogen bonding between their hydroxyls and the hydrated alumina surface. The alkyl groups are therefore directed away from the surface and thereby provide an effective low-energy screen against further adsorption. 

The thin inner shell of the core-shell polymers contained less than 20% rubber by weight, with 60% by weight of a plastic core in the particles. It is unusual to enhance the toughness of the normally brittle epoxy-resin system at such a low level of rubber content. We believe that the unique design, the use of a multilayer toughener with a thin, elastomeric inner layer, and the large plastic core together produced behavior like that of solid rubber particles and, hence, enhanced crack resistance. 

S-enantiomers. The unusual behavior of the J -enantiomer can be explained e.g. with multilayer adsorption processes (Mihibachler et al., 2001). A more detailed discussion related to consequences of inflection points in isotherm courses is given by Arnell and Fornstedt (2006). 

By alternating layers of hard and soft materials, such as polystyrene and polypropylene, it is possible to achieve synergistic effects in properties, similar to polyblending. For example, a better combination of stiffness, ductility, and toughness can be obtained in polystyrene-polypropylene multilayer films than in either component alone. Such materials also display unusual optical behavior, such as total reflection, at certain wavelengths (Alfrey et al., 1969), because the films tend to reflect light in a manlier similar to the reflection of x-rays by crystals. 

Electroformation allows the formation of giant vesides as large as 100 mm in diameter, induding some unusual multicompartment and multilayered stractures where vesides are encapsulated inside larger vesides in a peapod- or onion-like fashion. ... 

Most thermoforming operations produce a relatively large amount of scrap in each cycle. Scrap rates of 30% are not unusual. If the sheet is produced in one location and thermoformed in another, or if the material is multilayer, reuse of scrap is more difficult than in extrusion blow molding. 

In clinical analysis, precision, accuracy, speed, and low cost are important considerations. These goals have sometimes been achieved by unusual devices, e.g., disposable potentiometric cells made by planar multilayer film technology, similar to photographic films. Reduction of sensor costs has been attempted by mass production of sensors using technologies of the semiconductor industry (ISFETs). There still appears to be some instability problems with ISFET devices and they do not appear to be in routine use in the clinical field. 

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