Energy of cohesion

This expression can be roughly interpreted as the difference between the Gibbs energy of adhesion of the two phases and the sum of the Gibbs energies of cohesion for the two phases. 

To evaluate the free energy of cohesion in the hydrocarbon region of the monolayer, Wc, it is necessary only to obtain the value of W0, the free energy of desorption of the hydrocarbon in the absence of interac-... 

The surface tension of a pure liquid is a direct measure of the free energy or cohesion. For a solid, the surface free energy, which has the same dimensions as surface tension, is the measure of free energy of cohesion. Thus, for Substance i... 

Atomic beams, 31 Nanoparticles, 31 Force microsopy on coated surfaces, 31 Glass surfaces, 31 Mica, 32 Bilayers as thin films and as vesicles, 32 Cells and colloids, 33 Aerosols, 34 Bright stuff. Sonoluminescence, 34 Fun stuff, 34 Slippery stuff, ice and water, 34 What about interfacial energies and energies of cohesion Aren t van der Waals forces important there too, not just between bodies at a distance 35... 

WHAT ABOUT INTERFACIAL ENERGIES AND ENERGIES OF COHESION ... 

What about interfacial energies and energies of cohesion Aren t van der Waals forces important there too, not just between bodies at a distance ... 

While van der Waals interactions between unlike solids in a liquid can be attractive as well as repulsive, it is clear from the underlying thermodynamics [133,135] that like particles can only attract each other, with zero interaction in the limiting case. For interaction between particles of the same kind embedded in a liquid, this interaction is governed by the free energy of cohesion... 

If there is no agglomeration at finite values of the free energy of cohesion, then, for zero free energy of cohesion, least close packing of the sediment and hence a maximum in the sedimentation volume Vsej is expected. 

It is convenient to split the energy of cohesion U up into four parts... 

Fig. 4.18. Experimental energies of cohesion as a function of the number of d-electrons (n ) for the three transition metal series (adapted from Young (1991)).

The differences between interfacial and bulk molecular interaction energies are due mainly to the two-dimensional geometry of the surface and also to differences in interfacial structure and differences in magnitude of the molecular interactions at the interface, from those of the bulk. In principle, it would be possible to calculate the energy of cohesion between molecules within a single phase if the potential energy functions and the spatial distributions of all the atoms and molecules were known. Moreover, if the complete... 

It is obvious that V(D)Totai in Equation (578) corresponds to the free energy of cohesion, so that [V(D)Total = 2yx. Equating this to Equation (578) we obtain... 

The surface energy can be related to the interaction energy of molecules in the bulk. To show this, let us introduce the work (or energy) of cohesion, Wc. This quantity can be defined as the work of the isothermal process required to separate a column of matter having a unit cross-sectional area... 

The interaction energy between particles, usph (h), also has a minimum at distances close to molecular dimensions, i.e. h0 b. For sol particles with radius r the absolute value of the depth of this minimum is the energy of cohesion, uh in the contact between such particles in a coagulate ... 

Fig. IX-19. The isotherms of free energy of cohesion between methylated particles in aqueous solutions of methanol (7), ethanol (2), 1 -propanol (3), n-butanol (4) ip is the alcohol volume fraction 2 is the interfacial free energy, a]2, isotherm for solid paraffin - ethanol solution interface, estimated from contact angle measurements as AAAFf -aL cosG [17]...

Fig. IX-20. The isothenn of free energy of cohesion between methylated particles in aqueous sodium dodecylsulfate (SDS) solution of concentration c (7 ) and the interfacial energy, ct12 isothenn for methylated surface - SDS solution interface (2) estimated as -7rs (here 7t, is the two-dimensional pressure obtained from the corresponding adsorption isotherm) [ 17]...

These particles are in ceaseless, random motion (vibration and translation). This motion is a measure of their kinetic energy hence the name kinetic-molecular theory. Motion is limited in the solid and liquid states by cohesive forces. The energy of cohesion is potential energy. This is the energy which must be overcome when solids are melted and liquids are vaporized. 

Wg = W g. Equation 8 is generally applicable but, for low energy solids and liquids which display a finite contact angle. Equation 9 may be used to calculate the free energy of cohesion (from Eq. 8 and Eq. 3, i.e. the Young-Dupr6 equation). 

If two cylinders of unit cross-sectional area of a given material i are reversibly brought together to form a single continuous entity (see Fig. 1), the variation of free energy associated with this process is known as free energy of cohesion, AGfj (= -Wf, work of cohesion), defined by (10) ... 

This implies that a narrow junction point spectrum is required Gels in which the spectrum is broad, (ranging from lower to higher energies of cohesion) will be devoid of thixotropy. 

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