Preparation and characterization of polyelectrolyte-coated gold nanoparticles.

摘要: Gold nanoparticles of 5 nm diameter, stabilized by 4-(dimethylamino)pyridine (DMAP), were coated with poly(sodium 4-styrene sulfonate) (PSS) via electrostatic self-assembly. The suspension stability, monitored the gold surface plasmon band (SPB), was studied varying pH, PSS chain length, and concentration. Enhanced stability is obtained at pH 10 (above pKa DMAP) when polymer length matches or exceeds particle circumference. Solid state 13C NMR used to determine presence DMAP polymers after subsequent deposition weak strong polycations: poly(allylamine hydrochloride) (PAH) poly(diallyldimethylammonium chloride) (PDADMAC). At 10, remains associated nanoparticle first layer has been formed. When PAH PDADMAC are subsequently added 4.5, expelled, suspensions remain stable, zeta potential values indicate complete charge reversal. In case PDADMAC, however, not fully retained. retained but lower potentials a higher SPB shift degraded stability. For addition 9.5, both expelled becomes unstable. These differences in multilayer components rationalized terms flexibility, density, ability functional groups directly interact surface.