Molecular adhesion

Evans et al., 1995] Evans, E., Ritchie, K., and Merkel, R. Sensitive force technique to probe molecular adhesion and structural linkages at biological interfaces. Biophys. J. 68 (1995) 2580-2587... 

Evans and Ritchie, 1997] Evans, E., and Ritchie, K. Dynamic strength of molecular adhesion bonds. Biophys. J. 72 (1997) 1541-1555... 

When the water film is squeezed out, the thick water layer is removed and the surfaces are separated by lubricant film of only molecular dimensions. Under these conditions, which are referred to as BL conditions, the very thin film of water is bonded to the substrate by very strong molecular adhesion forces and it has obviously lost its bulk fluid properties. The bulk viscosity of the water plays little or no part in the frictional behavior, which is influenced by the nature of the underlying surface. By comparing with the friction force of an elastomer sliding on a rigid surface in a dry state, Moore was able to conclude that for an elastomer sliding on a rigid surface under BL conditions, one can expect ... 

Of the intrinsic properties the molecular adhesion the softening temperature and the relative hardness of the two materials are the most important. Friction is high when molecular adhesion is high therefore friction of a material with itself is usually higher than that with a dissimilar material. 

In certain cases, self-assembly methods can be employed to prepare multilayered thin films analogous to LB films. Typically, once the surface has been primed with a molecular adhesion layer, subsequent layers are assembled in a layer-by-layer fashion where the end group of the previously deposited layer directs the assembly of the next layer. Strong electrostatic or covalent interactions between the layers serve to stabilize the assemblies. The most notable examples of self-assembled multilayered films are those based upon metal phosphonates [21]. Although these multilayers are structurally analogous to LB films, their thermal and solvent stability makes them potentially more useful in many applications, including electron-transfer studies. 

Kendall, Kevin. Molecular Adhesion and Its Applications The Sticky Universe. New York Kluwer Academic/Plenum Publishers, 2001. 

Adhesion The adhesion of two different materials caused by atomic or molecular adhesive forces. 

A further problem that is associated with fine and ultrafine solids and can be remedied by size enlargement is that the entire mass of powder particles responds to the presence of the naturally existing molecular adhesion. This means that, in bulk, they adhere to each other and do not settle under the influence of gravity. 

Initially, with the completion of development wells, such fields, for a short time, give high yields of oil accompanied by a sharp drop in reservoir pressure. During that stage, the elastic forces of viscous oil and the energy of dissolved gas constitute the principal reservoir drives. Bound formation water also assists in displacing the oil from the reservoir by weakening the forces of molecular adhesion betwen the oil and the rocks. 

The secretion of the active substance by the leucocytes is not instantaneous it takes place slowly, and is hindered by cold. It appears very sensitive, as we have seen, to the influence of the wail of the vessel in which the blood is preserved. Blood, in contact with paraffin or vaseline, curdles more slowly than if it touches glass or porcelain. It is very probable that the phenomenon of molecular adhesion enters to accelerate the enzymic secretion, but it is necessary to observe that this explanation of the part played by the wall in the coagulation of blood is not exclusive. Bordet and Gengou, in experiments which we shall describe later, have, in fact, shown that plasma, deprived of every cell, is likewise much slower to coagulate in a parafiined vessel than in a glass vessel. It appears that other factors, which we shall study later, enter into this phenomenon. 

Two principle mechanisms that are discussed as possible corrosion protection mechanisms on mild steel are discussed in short. ICPs may induce the formation of a passive oxide [206]. The ICP will be reduced as a consequence of passivation and will be reoxidized by oxygen reduction. Consequently, the ICP may promote the cathodic oxygen reduction on the polymer surface rather than at the metal-polymer interface. On the basis of the good corrosion results gained by the combination of a molecular adhesion promoter and the subsequent electrodeposition of the polymethylthiophene film Rammelt and coworkers [207] concluded that the essential aspect of the corrosion protection by ICPs could be the local separation of iron oxidation and oxygen reduction. This would eliminate the local pH increase at the metal surface and subsequent cathodic disbondment. 

Mechanical properties of materials have recently been correlated to cellular or tissue responses [74,75]. To date, studies have demonstrated that stem cells and tissue cells (such as skin, muscle, and brain cells) sense and respond to local matrix (e.g., extracellular matrix or synthetic material) stiffness through the formation of molecular adhesion complexes and changes in the actin-myosin cytoskeleton, which provide a feedback of the matrix stiffness for cell adhesion, motility, and differentiation [74]. For example, epithelial cells and fibroblasts on a collagen-coated polyacrylamide substrate that allows the stiffness to be altered (elastic moduli from 5 to 80Pa) revealed less cytoskeletal spreading and higher rates of motility or lamelhpodial activity on flexible... 

INTRODUCTION TO MOLECULAR ADHESION AND FRACTURE THE ADHESION PARADOX... 

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