We will use SANS to characterize dispersions of gold nanoparticles functionalized with poly(dimethyl aminoethyl methacrylate) brushes grafted from 25 nm gold nanoparticle interfaces by surface-initiated ATRP. We will characterize the response of the polymer layers to pH and at at low pH, where the polymer is cationically charged, to electrolyte concentration. Our main focus however will be to determine the nature of the surfactant aggregates formed in the brushes at concentrations of surfactant that lead to peaks in the surface tension of the dispersions at pH=3 and 10 and also lead to the formation of multilayer structures in equivalent brushes formed at planar interfaces. We will measure under particle-matching contrast, for dispersions bearing hydrogenous pDMAMEA and particle-matching DMAEMA with particle-matching SDS and hydrogenous SDS respectively.