Effect of adsorbed polymers on electrophoresis of dispersed particles in strong electric fields

Electrophoresis in strong electric fields

“…As it was shown before [26][27], the ef velocity and ζ-potential of PS particles decreases with changing the adsorption of PEO and PVP from 0 to 1 mg m − 2 at V = 6 V/cm approximately by an order of magnitude, while this decrease in field of 200 V/cm is about two-fold (from 0.15 cm/s to 0.3 cm/s) and in higher fields this difference is even less. An analogous effect is observed for suspension of graphite particles: a ten-fold decrease in the velocity and ζ-potential of particles with increasing the PEO adsorption in the range from 0 to 0.8 mg m − 2 in weak fields [28] and it's only about 30-50% drop in strong electric fields, starting from 100 V/cm. This testifies our ideas that the effect of adsorbed non-ionic polymers on the electrophoresis in weak fields is due to the shift of the shear plane toward solution as a result of formation of hydrodynamically immobilised aqueous layers inside the polymer sheet, whereas the (much weaker) effect of adsorbed polymers on the ef movement in strong fields is connected with some decrease in the surface conductivity due to the presence of polymer segments in a small fraction of the space around the particles.…”

Novel lignosulfonate/N,N‐dimethylacrylamide/γ‐methacryloxypropyl trimethoxy silane graft copolymer as a filtration reducer for water‐based drilling fluids

“…Figure shows that with the increase of copolymer concentration, the zeta potential of bentonite‐based mud increases (absolute value). It reveals that the synthesized graft copolymer adsorbs dispersed clay particles, compresses the diffusive electric double layer of clay particles, increases zeta potential, and enhances the repulsive force between clay particles, which results in the relatively uniform dispersion of clay particles in WBDFs . The dense filter cake reduces the fluid loss of WBDFs.…”

Rheological Characterization of the Influence of PVOH on Calcite Suspensions

“…The ζ potential of the calcite particles as a function of PVOH concentration is shown in Figure . The ζ potential decreases smoothly as a function of PVOH concentration, which is believed to be due to a shift of the slipping plane further away from the surface leading to a screening of the effective charge. − These results can be used to estimate an “electrophoretic thickness” of the adsorbed layer, , which is discussed below. Also shown in Figure is the percentage of adsorbed PVOH, calculated from the equilibrium amount in solution.…”

“…An assumption is that the adsorbed PVOH does not alter the surface charge density and thus the potential decay from the surface is easy to calculate provided the surface potential is known. The surface potential is approximated at the Stern layer (∼0.4 nm from the physical surface), and the ζ potential at zero PVOH concentration is used as an approximate Stern layer potential. The electrophoretic thickness, h , can be calculated with the following equation: where ψ δ is the Stern layer potential at a distance δ (=0.4 nm) from the surface.…”

“…The surface potential is approximated at the Stern layer (∼0.4 nm from the physical surface), and the ζ potential at zero PVOH concentration is used as an approximate Stern layer potential. The electrophoretic thickness, h , can be calculated with the following equation: where ψ δ is the Stern layer potential at a distance δ (=0.4 nm) from the surface. The ionic strength is 0.0025, which is based on the dissolved amounts of calcium and carbonate ions .…”