Janus particles at walls modified with tethered chains.

We investigate the structure and adsorption of amphiphilic molecules at planar walls modified by tethered chain molecules using density functional theory. The molecules are modeled as spheres composed of a hydrophilic and hydrophobic part. The pinned chains are treated as tangentially jointed spheres that can interact with fluid molecules via orientation-dependent forces. Our density functional approach involves fundamental measure theory, thermodynamic perturbation theory for chains, and a mean-field approximation for describing the anisotropic interactions. We study the adsorption of the particles, focusing on the competition between the external field (due to the surface and due to attached chain molecules) and the interaction-induced ordering phenomena.