(230r) Size and Zeta Potential Behavior of Gold Nanoparticles –Polyelectrolytes Complexation

A complexation of nanoparticles with polyelectrolytes is a key factor in the process such stabilization and dispersion of nanoparticles in aquatic environment. The charged nanoparticles significantly affect the colloidal properties of a polyelectrolyte in water. The important physicochemical properties such as the polyelectrolyte size and zeta potential, nanoparticle size, nanoparticles zeta potential changes due to nanoparticles-polyelectrolyte complexation.  Dynamic light scattering (DLS) and zeta potential techniques were used for investigation of aggregate size and zeta potential of citrate-coated gold nanoparticles 50 nm (GNP-50) in complexation with humic acid (HA), poly(styrene maleic acid sulfonate) (PSMA), polyethylenimine (PEI) and polyacrylic acid sodium salt (PAA) separately. The aggregate size and zeta potential of gold nanoparticles and each polyelectrolyte were measured from the acidic (pH=2) to basic (pH=14) range and compared to complex of mixture of them.  For the complex of  GNP-PEI  and GNP-HA , the size and zeta potential of the complex showed a new trend or synergistic response marked by a unique shift in the isoelectric point of the polyelectrolyte when adsorbed onto the nanoparticle.   For the poly(styrene-maleic anhydride sulfonate) material no changes in size and zeta potential were seen. This behavior is explained by comparison to literature-based on Monte Carlo simulations.