The impact of the polar core size and external organic media composition on micelle–micelle interactions: the effect on gold nanoparticle synthesis

Abstract

We report the effect of the molar ratio parameter W₀ (W₀ = [water]/[surfactant]) and the external organic media composition on benzyl-n-hexadecyldimethylammonium chloride (BHDC) reverse micelle (RM) interactions, the key step to nanoparticle synthesis using RMs as nanoreactors. The results show a better interaction between BHDC RM droplets when the external media contain toluene:hexane blends instead of pure toluene. This organic solvent mixture enhances the material exchange between droplets and more well defined and smaller gold nanoparticles were obtained at the two W₀ studied (3 and 6). On the other hand, BHDC RMs created in pure toluene give a stiffer environment with poor droplet–droplet interaction, and the Cl⁻ counterions affect the growth of the particles, leading to different morphologies and sub-nanometer gold species production. These results are very promising for many applications. This work shows how each RM system is a unique and tunable nanoreactor.