Interaction of nonionic dextrans with silver bromide hydrosols

Interaction of dextran sulfates with positively and negatively charged silver bromide hydrosols

“…The adsorption occurs most likely via the unsubstituted OH group of the glucose rings. This observation is opposite to what was established with the same sols in the presence of nonionic dextrans (2). This finding would indicate that the flocculation mechanism cannot be related to the change in the electrokinetic properties of the particles.…”

“…The stock solutions of the dextran sulfates in water and water-methanol mixtures were prepared and purified in the same manner as the solutions of nonionic dextrans described earlier (2).…”

“…The methods for the preparation of the sols as well as the stability determinations were the same as given in the previous paper (2). In a series of systems all components were kept constant except the polymer, the concentration of which was varied gradually.…”

“…To characterize the samples of dextran sulfate, light scattering and viscosity determinations were carried out by procedures already described in detail (2). From light scattering, the molecular weights and the EM 243 28* radii of gyration of the polymers were obtained by graphical extrapolations of the experimental data according to Zimm (4).…”

“…In an earlier communication the effects of nonionic dextrans on the stability of silver bromide sols in stare nascendi had been discussed in detail (2). This w o r k describes the interactions of anionic polyelectrolytes, dextran sulfates, of different molecular weights and charge densities with the positively and the negatively charged silver bromide sols in water and in methanol-water mixtures.…”