Interfaces neutral surface

An electric potential drop across the boundary between two dissimiliar phases as well as at their surfaces exposed to a neutral gas phase is the most characteristic feature of every interface and surface electrified due to ion separation and dipole orientation. This charge separation is usually described as an ionic double layer. 

The presence of an electrical potential drop, i.e., interfacial potential, across the boundary between two dissimilar phases, as well as at their surfaces exposed to a neutral gas phase, is the most characteristic feature of every interface and surface electrified due to the ion separation and dipole orientation. This charge separation is usually described as the formation of the ionic and dipolar double layers. The main interfacial potential is the Galvani potential (termed also by Trasatti the operative potential), which is the difference of inner potentials (p and of both phases. It is a function only of the chemical... 

When the interface is charged, the Poisson-Boltzmann equation predicts stronger fields and higher ionic concentrations in the vicinity of the surface, therefore a dielectric constant smaller than in the bulk, and the local Born energy indicates that the ions are repelled by the interface. However, a neutral surface depleted of ions should have a dielectric constant larger than the bulk and the ions should be attracted, not repelled by such an interface. Therefore, other interactions should be included to explain the ion depletion near a neutral surface. 

More surprisingly, CyDs can in addition directly influence nanosphere characteristics by stabilizing interfaces during the preparation process, as described for emulsions [39]. Thus, it appears that the type of CyD used influences the particle size, their surface potential, and the total amount of CyD associated into the nanospheres [39]. Among CyDs, HP- 8-CyD leads to spheres with the smallest size (interesting in parenteral administration) and a neutral surface. 

The neutral surface is obtained by choosing the shift in the interface position, A, so that there are no terms in /(17, H, K) where the area and curvatures are coupled. From Eq. (6.13), one sees that this is the case when... 

Based on the discussion in the text, calculate the bending modulus, gi, for deformations relative to the neutral surface in terms of the parameters that describe the bending at some other surface ie.g., the polar-nonpolar interface), fu //. /o". 

---