Adhesion free energy

Free energy of adhesion Free energy of cohesion Free energy of spreading Glass transition temperature Rate of energy input to filament Volume... 

Finally, Newmann and co-workers [30] (see also Ref. 31) have argued that while free energy contributions may not be strictly additive as in Eq. IV-11, there should, in principle, be an equation of state relating the work of adhesion to the separate liquid surface tensions such as... 

The interfacial free energy per unit area is given by the adhesion force Fo/lrR", estimate the Hamaker constant responsible for the adhesion force in the crossed-cylinder geometry illustrated in the inset to Fig. VI-6. 

Returning to more surface chemical considerations, most literature discussions that relate adhesion to work of adhesion or to contact angle deal with surface free energy quantities. It has been pointed out that structural distortions are generally present in adsorbed layers and must be present if bulk liquid adsorbate forms a finite contact angle with the substrate (see Ref. 115). Thus both the entropy and the energy of adsorption are important (relative to bulk liquid). The... 

While the surface tension of the adhesive, is easily measured in the laboratory, the other terms in Wa, by themselves, are not. A second easily measurable property associated with the solid-liquid-air system, however, is the contact angle, 9, the angle, drawn in the liquid, between the solid-liquid and the liquid-air interfaces, drawn in the plane perpendicular to the three-phase interline, as shown in Fig. 4. Minimization of the free energy of the solid-liquid-air... 

The effect of the chemical makeup of the adhesive/adherend system on contact angle and wetting is manifest through the influence of such chemistry on the surface free energies of the adhesive-air (or other fluid medium), adherend-air... 

Most polymer pairs are thermodynamically incompatible, in the sense that their free energy of mixing is positive. This does not mean that there is absolutely no interdiffusion at all at the interface between them adjacent to the interface limited interdiffusion occurs, which can be seen as an increasing of the low surface entropy implied by a smooth surface [30-33]. This nanoscale roughening of an interface can increase the adhesion between the polymers. 

Oxidation of polyethylene by sulphuric acid and potassium chlorate [9,10] improves its adhesiveness. The free energy of adhesion of the polymer is found to increase linearly with the surface density of the hydrophyl-lic sites created by oxidation. 

The adsorption theory states that the bioadhesive bond formed between an adhesive substrate and tissue or mucosae is due to van der Waals interactions, hydrogen bonds, and related forces. Alternatively, when mucus or saliva are interacting with a solid dosage form, the molecules of the liquid are adsorbed on the solid surface. This is an exothermic process. The free energy of adsorption is given by Eq. (1). 

Freitas, A. A., Quina, F.H., and Carroll, F.A. Eshmahon of water-organic interfacial tensions. A linear free energy relationship analysis of interfacial adhesion, J. Phys. Chem. B, 101 (38) 7488-7493, 1997. 

E(hg) is negative for adhesive systems and —E(he) is traditionally known as the free energy of adhesion. 

---