Films form adherent

Tungsten disulfide forms adherent, soft, continuous films on a variety of surfaces and exhibits good lubricating properties similar to molybdenum disulfide and graphite (51) (see also Lubrication and lubricants). Itis also reported to be a semiconductor (qv). 

Copolymers wet and adhere well to nonporous surfaces, such as plastics and metals. They form soft, flexible films, in contrast to the tough, horny films formed by homopolymers, and are more water-resistant. As the ratio of comonomer to vinyl acetate increases, the variety of plastics to which the copolymer adheres also increases. Comonomers containing functional groups often adhere to specific surfaces for example, carboxyl containing polymers adhere well to metals. 

Metals that depend on a relatively thick protective coating of corrosion product for corrosion resistance are frequently subject to erosion-corrosion. This is due to the poor adherence of these coatings relative to the thin films formed by the classical passive metals, such as stainless steel and titanium. Both stainless steel and titanium are relatively immune to erosion-corrosion in most cooling water environments. 

Thin sheets of mica or polymer films, which are coated with silver on the back side, are adhered to two cylindrical quartz lenses using an adhesive. It may be noted that it is necessary to use an adhesive that deforms elastically. One of the lenses, with a polymer film adhered on it, is mounted on a weak cantilever spring, and the other is mounted on a rigid support. The axes of these lenses are aligned perpendicular to each other, and the geometry of two orthogonally crossed cylinders corresponds to a sphere on a flat surface. The back-silvered tbin films form an optical interferometer which makes it possible... 

There are many temporary protectives on the market and it would be impracticable to describe them individually. However, they may be classified according to the type of film formed, i.e. soft film, hard film and oil film the soft film may be further sub-divided into solvent-deposited thin film, hot-dip thick film, smearing and slushing types. All these types are removable with common petroleum solvents. There are also strippable types based on plastics (deposited by hot dipping or from solvents) or rubber latex (deposited from emulsions) these do not adhere to the metal surfaces and are removed by peeling. In addition there are volatile corrosion inhibitors (V.C.I.) consisting of substances, the vapour from which inhibits corrosion of ferrous metals. 

Cationic and hydrophobe modified polysaccharides are preferred excipients for personal care products since they are substantive (adherent) to anionic or hydrophobic substrates (skin, hair, mucosa), hydrophilic, film forming, compatible with many therapeutic agents, nonpenetrating, and nonirritating. Polymer JR and Quatrisoft (Figure 1), are two such materials... 

To demonstrate film-forming properties of the latex, prepare a drawdown bar by adhering a double thickness of adhesive tape to each end of a glass rod. 

Paints are commonly divided into oil-base, or solvent systems, and latex, or water-base, paints. These paints are essentially a suspension of inorganic pigments and a resin, or vehicle, in a suitable solvent. Paints protect wood surfaces by forming an ultraviolet absorbing film that adheres strongly to the surface. 

One of the primary advantages of the polycide concept is that the silicide top layer oxidizes readily to form a dense adherent Si02 overlayer, and the polycide structure underneath remains intact. Also, the oxide film forms within a reasonable time. Oxide thicknesses formed by dry 02 oxidation are shown in Figure 10, as a function of time and temperature. 

The mercury film electrode (MFE), used for stripping analysis or flow amperometry, consists of a very thin (10-100-pm) layer of mercury covering a conducting and inert support. Because of the adherent oxide films on metal surfaces, and the interaction of metals with mercury, glassy carbon is most often used as a substrate for the MFE. The mercury film formed on a glassy carbon support is actually composed of many droplets. Because they do not... 

Corrosion is the oxidation of a neutral metal atom to form a positive ion. The reason that this is not a desirable reaction is that the positive ion form of a metal is generally soluble and so the corrosion weakens the metal. In some cases, the oxidation actually creates a protective film over the metal. As aluminum oxidizes, the Al203 formed adheres so strongly to the aluminum metal that it protects the aluminum from further oxidation. Millions of dollars a year are spent in the management of corrosion in the home and in industry. 

LPD deposition of ceramic thin films is a potentially general approach to improving the abrasion resistance and thermo-oxidative stability of polymers. Dutschke et al.14,15 have deposited titania on variously treated polystyrene (PS). Continuous, adherent anatase films form on PS either after hydroxylation in... 

Though Method 2 had been reported12 to give adherent titania films only on sulfonated surfaces, we compared PMR-15 with and without CISO3H activation in a 22-h deposition. In both cases, adherent anatase films with significant (004) orientation formed, 660-690 nm on the sulfonated surface and 520-630 nm thick on the untreated substrate (Table 1). In a similar study on PS,15 films formed with or without grafted sulfonic acid groups on the surface, but were only adherent on the sulfonated surface. 

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