1. Surfactant adsorption and self-assembly at solid/liquid interfaces
Steven O. Nielsen, Department of Chemistry, University of Texas at Dallas
We have examined the behavior of nanoparticles coated with amphiphilic ligands at oil/water interfaces, with a ligand coverage determined from self-consistent free energy. In order to be sure of capturing the full range of experimental possibilities, we have simulated the two extremes of chain attachment to the nanoparticle: fixed, equidistance attachment points (shown in panel A), and mobile attachment points (shown in panel E). The latter case is meant to account for the strong experimental evidence that the ligand coating is at equilibrium (e.g. from ligand exchange experiments). Surprisingly, even for the very short C12E2 chains used here, it makes almost no difference which attachment model we use.
This is evident from the chain behavior when the nanoparticle is on the water side (panels B and F), on the oil side (panels D and H), or precisely at the oil/water interface (panels C and G). Thus even short chains distort enough that the attachment point is not critical.