Wetting theory

Wetting, theory, 530 Windows, smart, 364 Work function... 

Comparison of Detergency Performance with Experimental and Thermodynamic Wetting Theories... 

The wetting theory is applicable to liquid bioadhesive systems. According to this theory, the ability of a bioadhesive material to spread and determine an intimate contact with the biological substrate plays a major role in bond formation [44], This theory uses interfacial tensions to predict spreading and, in turn, bioadhesion. In the past, the surface energy of both bioadhesive materials and tissues or mucus have been extensively studied to predict the bioadhesive performance [47-49]. 

According to the very popular wetting theory a material (bioadhesive, phase b) displaces the surrounding liquid (e.g. the gastric content, phase g) and adheres spontaneously on the mucus (tissue, phase t) when the spreading coefficient, Ws(b), is positive, i.e. ... 

There is no unified theory to explain the process of mucoadhesion. The total phenomenon of mucoadhesion is a combined result of all these theories. First, the polymer gets wet and swells (wetting theory) followed by the noncovalent (physical) bonds created within the mucus-polymer interface (electronic and adsorption theory). Then, the polymer and protein chains interpenetrate (diffusion theory) and entangle together to form further noncovalent (physical) and covalent... 

The poor wetting theory leaves several questions unanswered. Chen et al. (35) argued that above the minimum wetting rate, wettability and surface tension should only have a minor effect on packii efficiency. Also, high relative volatility and hi liquid viscosity q>pear to be detrimental to efficiency, especially in aqueous systems, and this cannot be explained by poor wettability. Finally, there is uncertain regarding the concetitration at which the transition firom an organic system HETP to an aqueous system HETP takes place. 

Mechanical Theory Electrostatic (Electronic) Theory Diffusion Theory Wetting Theory Chemical Bonding 1.6.5.1 Acid-Base Theory Weak Boundary Layer Theory... 

It is curious that the conventional wetting theory has not been more widely challenged, since the most commonly studied nanopatterned hydrophobic surfaces are plant leaves covered with inherently hydrophilic epicuticular waxes. For example. 

In which y is the interfacial tension, 0 the contact angle, K a correction factor for the shape of the pores and d the pore diameter. Cos 0 is determined by the interfacial tensions between the three components filter membrane material, hquid and air. It is the same angle as in the wetting theory as discussed in (Sect. 18.3.2). The manufacturer supplies the value of the bubble point for hydrophilic filters for a filter moistened with purified water at a specified temperature. A different liquid or product or different temperature in the membrane results in a different interfacial tension and thus a different bubble point. 

Spaull, A.J.B., Cahn s perfect wetting theory in determining monolayer capacity, J. Chem. Technol. Biotechnol., 57(1), 87-92(1993). 

All the studies conducted on fracture of bulk polymers are certainly relevant to the adherence of polymers, the mechanisms of losses at a crack tip being the same viscoelastic losses due to moving stresses, work to extract chains or fibrils, and viscous drag in the presence of a liquid. It is probable that the various theories of adhesion, namely, theory of wetting, theory of the rheological factor, theory of the chemical bond, theory of the weak boundary layer, and theory of interdiffusion, are all valid, each corresponding to an emphasis on a dominant mechanism. 

In view of the various assumptions and approximations made, the result may be regarded as tentative. Despite the many weak links in the knowledge of the properties of strength and the equivocality of the wetting theory, the agreement between the theory and experiments is deemed more than merely fortuitous. 

The analysis makes use of relaxation and retardation spectra of elastomers. The estimation of the magnitude of friction has not yet been attempted. However, a major step towards that goal has been shown. In particular the wetting theory has been found to be useful in describing the strength of a countersurface in adhesion. 

Fruitful discussions on wetting theories with P.G. de Gennes and J.F. Joanny are gratefully acknowledged. 

BeUanger H, Darmanin T, deGivenchy ET, Guittard E (2014) Chenucal and physical pathways for the preparation of superoleophobic surfaces and related wetting theories. Chem Rev 114 2694-2716... 

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