Total surface energy

Polymer Surface energy, total, mJ/m Surface energy, dispersion component, mJ/m Surfaee energy, polar component, mJ/m ... 

The total surface energy generally is larger than the surface free energy. It is frequently the more informative of the two quantities, or at least it is more easily related to molecular models. 

Fig. III-2. Variation of surface tension and total surface energy of CCU with temperature. (Data from Ref. 2.)...

The surface free energy can be regarded as the work of bringing a molecule from the interior of a liquid to the surface, and that this work arises from the fact that, although a molecule experiences no net forces while in the interior of the bulk phase, these forces become unbalanced as it moves toward the surface. As discussed in connection with Eq. Ill-IS and also in the next sections, a knowledge of the potential function for the interaction between molecules allows a calculation of the total surface energy if this can be written as a function of temperature, the surface free energy is also calculable. 

The calculation is made by determining the primary contribution to the surface energy, that of the two separate parts, holding all the atoms in fixed positions. The total energy is reduced by the rearrangement of the surface layer to its equilibrium position as... 

Side (cm) Total Area (cm ) Total Edge (cm) Surface Energy (ergs/g) Edge Energy (ergs/g)... 

The illustrative data presented in Table VII-3 indicate that the total surface energy may amount to a few tenths of a calorie per gram for particles on the order of 1 /xm in size. When the solid interface is destroyed, as by dissolving, the surface energy appears as an extra heat of solution, and with accurate calorimetry it is possible to measure the small difference between the heat of solution of coarse and of finely crystalline material. 

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... 

These equations result from assuming that the total surface energy can be split into the sum of components associated with different types of bonding, for example dispersion plus polar yP (Eqs. 14 and 15), or Lifshitz-van der Waals... 

It is observed that the total surface energy increases with grafting (Table 5). The values become almost double for PEgDBM3. The increased surface energy of the grafted polymer comes mostly from the polar compo-... 

The total surface energy 7. together with 7s " (Liftshitz van der Waal s component), 7, (acidic component), 7s (basic component), and 7s (acidic and basic component) have been determined for the modified and control EPDMs. The results are plotted against radiation dose in Figure 31.6. 

The shape of a droplet or of the front end of a film can be determined from the surface energies and interaction forces between the interfaces. These also determine the equilibrium thickness of a liquid film that completely wets a surface. The calculation is done by minimization of the free energy of the total system. In a two-dimensional case the free energy of a cylindrical droplet can be expressed as [5] ... 

In metal deposition, the primary products form adsorbates on the electrode surface rather than a supersaturated solution. Their excess chemical potential is directly related to polarization and given by nFAE. The total excess surface energy = 2 S,o,. Otherwise, all the results described above remain valid. 

The surface energy produced by fracture is small when compared with the total mechanical energy stored in the material at the time of fracture, and most of the latter is transformed into heat. This leads to the crushing efficiencies to be low and results show them range between 0.1 and 2%. 

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