Films unidirectionally oriented

Figure 3. Unidirectionally oriented A-S-D triads in LB films containing 15 alternate bilayers consisting of a triad-CaT (1 5) and a pure CaT monolayer. In type a (a), the D tails of A-S-D triads orient towards the air, while in type b (b) the tails orient towards the substrate plate.

SSPM of alternate LB films containing unidirectionally oriented A-S-D triads... 

Figure 17. The change in the surface potential by step illumination for ca. 2-3 s with a He-Cd laser of 441.6 nm in a total reflection mode on (a) a type a alternate and (b) a type b alternate LB film containing 15 unidirectionally oriented A-S-D triad monolayers, and (c) a black LB film.

Infrared linear dichroism measurements may be performed on unidirectionally oriented samples. In the case of DNA, the favored axis of orientation is the axis of the double helix. Films are prepared by unidirectional stroking while the sample is gently dried. Two spectra are recorded with the electric field of the incident light oriented parallelly... 

M. Fujihira, H. Yamada, Molecular Photodiodes Consisting of Unidirectionally Oriented Amphipathic Acceptor Sensitized Donor Triads , Thin Solid Films, 160, 125 (1988)... 

A fairly recent development is the manufacture of cross-laminated unidirectionally oriented films which can be used for the manufacture of sacks. Rasmussen " invented this process in which films are spirally cut from unidirectionally stretched tubes and laminated by means of an adhesive. The orientation directions of both layers are perpendicular to each other and at an angle of approx. 45° to the longitudinal direction of the laminate. Sacks manufactured from cross-laminated high-density polyethylene film have very high strength, tear strength and puncture resistance and are sold under the trade name Valeron . 

For the SMM studies of LB films containing unidirectionally oriented A-S-D triads, the alternate LB multilayer systems shown in Fig. 26 are constructed [95]. In the LB assemblies, linear-type A-S-D triads are arranged unidirectionally in two ways with the D tail of the triad toward the air (a) or toward the substrate plate (b), respectively. For the fabrication of these LB assemblies, a fatty acid is used as a... 

Molecular orientation is another important factor influencing mechanical properties of coextruded films (11). Biaxial orientation can greatly improve film strength. However, uniaxial or highly unbalanced orientation causes poor transverse properties, which result in easy splitting of coextruded films in the machine direction. This tendency may occur even when a relatively thin layer responds to unidirectional orientation and propagates failure to thicker adjacent layers. 

Preparation of a new type of nanostructured composite thin film in which one component possesses unidirectional order while the other component is randomly oriented. 

Orientation consists of a controlled system of stretching TP molecules in unioriented [unidirectional (UD)] or bioriented [biaxial direction (BD)]. UD orientation can be in the machine direction (MD) or transverse direction (TD).207 Orientation improves strength, stiffness, optics, electrical, and/or other properties with the usual result that improved product performance-to-cost occur. This technique is used during the processing of many different products such as films, sheets, pipes, fibers, tapes, etc. 

The actual coefficient of friction of a molybdenum disulphide film will depend on the integrity of the film, contact pressure, temperature, humidity, film thickness and presence of contaminants. For a pure, smooth, dense, properly-oriented film at high contact pressure in a clean, dry atmosphere in unidirectional sliding, coefficients of friction as low as 0.02 have been reported. With impurities, poor orientation, humidity and low pressure, the coefficient of friction may be as high as 0.3. 

Lancaster studied the transfer of molybdenum disulphide and graphite to low-carbon steel discs from compacts. The compacts were formed at relatively low pressures, up to 80 MPa, but later work ° indicated that when compacts were formed at higher pressures up to 1500 MPa, there was no obvious difference in the nature of the transfer films produced from them. It can therefore be assumed that the crystallites in the compacts were mainly randomly oriented, although there is some evidence that in unidirectional pressing of a lamellar solid a relatively high degree of orientation occurs in the surface layers. 

In Figure 12.9 (a), (i) there are six 111 diffraction poles, rather than three, around the central (111) pole, and (ii) three diffraction poles, (111), (111), and (111) are more intense that the other poles, (111), (111), and (111). The result (i) indicates that there are two possible orientations of diamond crystals that are rotated by 60° in plane with respect to each other. A similar type of orientational structure has been observed for p-SiC(l 11) epitaxially grown on 6H-SiC(0001) [395]. In this case, incoherent boundaries, called double positioning boundaries, are formed in the film by 60°-rotated domains. On the other hand, the result (ii) indicates that the three orientations, (111), (111), and (111), are preferable to other three orientations. The existence of non-equivalent diamond orientations on the Pt(lll) surface was attributed to interactions with the second nearest neighbor Pt atoms. However, the incoherent boundaries due to the existence of 60°-rotated diamond crystals have not been identified yet. It is of interest that an azimuthally unidirectional surface was formed as the diamond CVD was continued for a longer time, as seen in Figure 12.7 (b). 

Desper, C. R., Stein, R. S. Measurement of pole figures and orientation functions for polyethylene films prepared by unidirectional and oriented crystallization. J. Appl. Phys. 37,39W(1966). 

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