Effects of adsorbed polyelectrolytes on convective flow and diffusion in porous membranes

摘要: Poly(acrylic acid) and poly(styrene sulfonate) were adsorbed from aqueous solutions to track-etched mica membranes with pores of radius 290 1400 A. Effects the polymers on momentum mass transport within studied by measuring decrease in both hydraulic diffusional permeabilities caused presence polymers. The permeability was determined flux a small, uncharged solute molecule (thiourea). Polymer-free, potassium chloride (KCl) used all experiments. reduction increased KCl concentration range 10-2 10-1 molarity (M), but independent electrolyte below M, presumably because small constrained expansion polymer chains. Shear thickening effects, that is, increasing solvent velocity through pores, observed at M 600 A or smaller. thiourea, other hand, relatively insensitive concentration. Perhaps most significant result is substantially less than each pore size concentration, indicating blockage these greater diffusion solute. Measurements thiourea simultaneous convection over Peclet numbers -2 +2 showed filtered polymer. This filtration probably not due steric limitations rather it likely excluded water which solvated densely packed regions