INDEX electrostatic stabilization

The surface viscosity or resistance to shear stress of the surface film is an index of its mechanical strength and is an important parameter related to the stability of films and foams ( ), Surface yield stress of BSA films were determined using the above parameters ( ). Maximum values were obtained in the pH range of 5-6, near the isoelectric point of BSA, and decreased rapidly above pH 6,0 [Table 1]. These observations again reflect the enhanced intermolecular interactions between protein components in the film as the isoelectric point is reached and the enhanced electrostatic repulsion between neighboring molecules as the pH is raised above the isoelectric point, i.e. net charge on the protein surface was increased. 

Similarly to the use of other physico-chemical parameters in characterizing the solvent effect, models based on an electrostatic approach have been produced for the description of the solvent dependence of the absorption spectrum these models describe the shifts of the absorption bands in terms of the relative permittivity and refractive index of the solvent [Oo 54, Ba 54], These have fairly limited validity, however, since specific coordinative interactions cannot be neglected when considering the factors that determine the stabilities of solvates. 

---