Experimental study and dissipative particle dynamics simulation of the formation and stabilization of gold nanoparticles in PEO–PPO–PEO block copolymer micelles

Gold nanoparticles in the range of 5 to 100 nm in diameter were synthesized by simply tuning the concentration of aqueous poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (PEO–PPO–PEO) block copolymer solution. As the copolymer concentration increased, the surface plasma resonance (SPR) of gold nanoparticles red-shifted and became more symmetrical. At the same time the gold nanoparticles became smaller and more uniform in size. Dissipative particle dynamics simulations indicated that PEO–PPO–PEO block copolymers formed micelles on the surface of particles, providing a protective layer to stabilizing them. Formation of uniform, small and stable gold nano-particles required that the copolymer be able to form micelles and that the core of the latter be hydrophobic.