Effect of Ligand Molecular Weight and Nanoparticle Core Size on Polymer-Coated Gold Nanoparticle Location in Block Copolymers

Gold nanoparticles modified by short chain polymer thiols [Au-PS] can be designed to strongly localize in either domain of a polystyrene-b-poly(2-vinylpyridine) [PS-PVP] block copolymer or at the interface. The P2VP block has a stronger attractive interaction with bare gold than the PS block. Thus, when the areal chain density $\Sigma $ of end-attached PS chains falls below a critical areal chain density $\Sigma c$ the Au-PS nanoparticles adsorb to the PS-b-P2VP interface. The effect of the polymer ligand molecular weight on the $\Sigma c$has been shown to scale as $\Sigma c\sim $ ((R+Rg)/(R*Rg))\^{}2, where R is the curvature of the Au nanoparticle core radius. To test this scaling relation for $\Sigma c$ further we are synthesizing gold nanoparticles with different core radii and will present preliminary results on $\Sigma c$as a function of R.