Equilibrium surface tension anionic-cationic

Diffusion NMR can indicate the formation of aggregates (e.g., micelles, emulsions). In the case of l-alkyl-3-methylimidazolium ibuprofenate ([C CJ[Ibu]) in water, the diffusion coefficients of cation and anion were found to be different, yet the CMC values obtained from the diffusion measurements for the cation and anion were identical, thus confirming that they were both participating in aggregate formation (Fig. 2.20) [57]. Moreover, the CMC values were in agreement with those obtained by other techniques (surface tension, conductivity). Because of the dynamic equilibrium between monomer and micelle, the observed diffusion coefficient is the mean value of the two states. If the exchange kinetics between the two states is fast on the diffusion time scale, the measured diffusion coefficient can be expressed as... 

The interactions of droplets/fluid protrusions with electric fields were considered in a set of papers going back as far as to the year 1882 concentrating predominantly on pendent and, to a lesser extent, on sessile droplets [27]. A frequent assumption is that the fluids to be spun such as polymer solutions or polymer melts tend to display an ionic conductivity to some degree. Within the electric field the anions or cations become nonuniformly distributed on the surface of the droplets in such a way that the surface becomes equipoten-tial and the field inside the droplet zero. The general result of the theoretical analysis is that such droplets are deformed within the electrical field and display a stable critical shape even when close to a critical electric field beyond which jet formation occurs from the tip of the deformed droplet (Fig. 3). The shape should in principle be controlled by the equilibrium between the electric forces and surface tension as far as viscous and viscoelastic fluids are concerned, whereas nonrelaxing elastic forces may also affect the shape of the droplet. Yet, the papers on droplet deformation differ in the mathematical approaches taken and in their predictions on the shapes of the deformed droplets. 

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