Fabrication of gold nanoparticle–polymer composite particles with raspberry, core–shell and amorphous morphologies at room temperature via electrostatic interactions and diffusion

Abstract

Composite particles with varying morphologies composed of gold nanoparticles (Au NPs) and polymers were fabricated based on a combination of electrostatic interactions between the polymer particles and Au NPs and diffusion processes. The positively charged polymer particles were prepared from amino-terminated polystyrene (PS-NH₂) and amino-terminated 1,2-polybutadiene (PB-NH₂). Adsorption of citrate-stabilized Au NPs resulted in three different distribution states of Au NPs in the polymer particles, depending on the glass transition temperature (T_g) and molecular weight of the polymer. The adsorption of Au NPs onto PS-NH₂ particles produced raspberry-like composite particle morphologies, while the NPs instead diffused into the PB-NH₂ particles, since the T_g of PB-NH₂ is below room temperature. The diffusion of Au NPs could be controlled by varying the molecular weight of the PB-NH₂ and the diameter of the NPs, and both core–shell and amorphous distributions were successfully achieved.