Total Work of Adhesion

Upon combining Eqs. 88 and 85, one finds that the total work of adhesion is related to the surface energies of the contacting materials as well as the enthalpy associated with acid-base interactions by... 

TWA, total work of adhesion MDF, maximum detachment force. 

After the determination of the dispersive work of adhesion from the Hexane experiment the total work of adhesion can be determined for Dichloromethane. This probe molecule represents a monopolar acid according to the van Oss concept and can be therefore used to determine the base number (ys ) of the surface. For the corresponding determination of the acid number the measurement with a monopolar basic probe molecule is required. Typical candidates for this would be either Toluene or Ethyl acetate. These measurements haven t been completed yet. For this reason the ys -values in the result table are missing. 

The total work of adhesion Wt, follows by summation over all types of interaction [Eq. (2)], presenting the correlation with the macroscopically measured adhesive bond strength, here the peel strength. 

For nonpolar materials involving only dispersion forces such as simple alkanes d = and a = (7. Fowkes developed an expression for the dispersion force contribution to the total work of adhesion of the form... 

This concept has been used to characterize the acidity and basicity of carbon fiber surfaces [162]. It is useful to recall that, according to Fowkes [163,164], the total work of adhesion, Wsl, is dependent on the pH of an aqueous solution, according to its two components ... 

FIGURE 3.8 Schematic representation of the work of adhesion versus pH for surface-oxidized carbon fibers. Wjl is the total work of adhesion, is the work of adhesion due to van der Waals/Lifshitz dispersion interactions, is the work of adhesion due... 

There is another contribution to the energies of interaction due to the van der Waals energies of attraction. In this case, the value is calculated separately (102) as -0.115 J/m, yielding a total work of adhesion of -0.21 J/m. ... 

The component of the surfaces under investigation can be determined by contact angle measurements, using a nonpolar liquid as the interaction of a nonpolar liquid is restricted to dispersive forces [83], The nonpolar liquid should have a high surface tension (such as DIM) to avoid the spreading of the liquid. In the case of negligible acid-base interactions (i.e., for nonpolar solids), the total work of adhesion between a solid and a liquid... 

When a solid surface involves both the Lifshitz-van der Waals and acid-base interactions, the total work of adhesion should be the sum of the following two components ... 

Any argument of this subject generally originates from the lack of understanding of modern polymer adhesion theories. Polymer adhesion largely involves the deformation of the polymer " , and to a lesser extent the thermodynamic work of adhesion as depicted by the absolute rate theory. Only for a very thin film does the thermodynamic work of adhesion determine the total work of adhesion. The thicker the polymer, the stronger the influence of the deformation properties. ... 

Fowkes proposes that the London dispersive part of the work of adhesion is quantified as twice the geometric mean of the dispersive component of the surface energy of solids 1 and 2. The total work of adhesion reduced to ... 

Polymer Total work of adhesion ( jJ) Adhesion time (h)... 

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