Adhesion between surfaces

Liquid or solid films which reduce or prevent adhesion between surfaces solid-solid, solid-paste, solid-liquid. Waxes, metallic soaps, glycerides (particularly stearates), polyvinyl alcohol, polyethene, silicones, and fluorocarbons are all used as abherents in metal, rubber, food, polymer, paper and glass processing. 

Adhesion between surfaces whereby valence forces predominate that are similar to those promoting cohesion. 

Stuart and Hlady [37] found that unintentional lateral forces influenced their measurements of adhesion between surface-bound protein molecules and colloid probe-bound ligands. They noted a greatly exaggerated separation distance and a stick-shp behavior in their adhesion curves, which they attribute to roUiug and buckling of the cantilever under the influence of lateral forces as the sample was retracted with the probe stuck to it. 

Eriksson M, Notley SM, Pelton R, Wagberg L. The role of polymer compatibility in the adhesion between surfaces saturated with modified dextrans. J Colloid Interface Sci 2007 310 312-320. 

Such copolymers may also be effectively employed to enhance adhesion between surfaces of different composition using copolymers with groups having different activity. These complex systems obtained by reaction (graft, block, homopolymers) have been termed interpolymer. For these and additional reasons, increasing amounts of block and graft copolymers are produced by the major plastics companies throughout the world. 

Research on friction has concentrated on the quantitative description of the areas of actual contact, the strength of adhesion between surfaces, the shear strength of the interface, interactions between A and S, the deformation component P, and interaction between the deformation and adhesion. 

The most important requirements to assure good adhesion between surfaces are the cleanliness and chemical and physical condition of the surfaces. The adhesive chosen must be able to wet the surfaces so that a contact angle of less than 90° results, as... 

Reasons for nse good spreading characteristics, improvement of prodnction rate, redaction of adhesion between surface of equipment and plastic materials in contact (mostly during their production)... 

Polymers in solution have an enormous effect on the adhesion between surfaces. Such polymers are used as lubricants, as thickeners, as colloid stabilisers, as binders, glues, and inks. Also they are ubiquitous in biological systems. Their practical significance is large but understanding their effects remains to be explored to a great extent. This section describes some experimental observations of the adhesion forces and draws a schematic theoretical picture of the effects. 

Obviously, roughness is a barrier which inhibits molecular contact and strong adhesion between surfaces. But more significantly, the roughness does not usually deform elastically as the surfaces make contact, as shown in Fig. 8.2. 

Adhesion, mechanical—Adhesion between surfaces in which the adhesive holds the parts together by interlocking action. (See also adhesion, specific.)... 

Adhesion, specific—(sometimes called adhesion, molecular). Adhesion between surfaces which are held together by valence forces of the same type as those which give rise to cohesion. (See also adhesion, mechanical.)... 

Increasing or reducing adhesion between surfaces, depending on the substrate and method of application, for example, surfaces of organic films, glass, and metals. 

Fig. 8 Diagram of the three sub-processes in the use of pre-formed PECs as a strength agent (7) PEC formation, (2) PEC adsorption onto a surface and (i) effect on adhesion between surfaces...

Ankerfors C (2012) Polyelectrolyte complexes prcparatimi, characterization, and use for control of wet and dry adhesion between surfaces. KTH Royal Institute of Technology, Stockholm... 

The surface energy has an immediate effect on the adhesion between surfaces, which nowadays is an important issue in MEMS. 

Fatty acid amides are well known as an important class of polymer additives used as a slip agent or lubricant to prevent unwanted adhesion. Unfortunately the addition of such amides for the purpose of antiblock additives for polymer sheets, in glass laminates (reduction of imwanted adhesion between surfaces of the polymer sheet itself) adversely affects the optical characteristics of the polymer sheet, such as haze, transparency, and film clarity, as well as adhesion of the polymer sheet to glass. Consequently, the inclusion of fatty acid amides polymer sheet interlayers in glass laminates is necessary. 

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