THE EFFECT OF CHITOSAN ADSORPTION LAYERS ON THE STABILITY OF GOLD HYDROSOLS

The stability of gold sol was studied by the optical spectroscopy meth od in a wide concentration range of chitosan solutions by varying the pH of a medium. It was shown that at pH 4.0 and high effective macromo lecule charge, the alternation of the stability and flocculation zones of negatively charged sol particles was observed with an increase in the polymer concentration. At high polyelectrolyte concentrations, the sol retains its aggregation and sedimentation stability due to the ch arge reversal of the particle surface and the prevalence of electrosta tic repulsion. At pH 6.0 and a low macromolecule charge, an increase i n the polymer concentration does not result in system stabilization. I n this case, sedimenting flocs are formed where the gold particles are separated by thick chitosan adsorption layers.