(362c) Forces Between Nanorods with End-Adsorbed Chains In Polymer Melts

Adsorbed or grafted polymers are often used to provide steric stabilization of colloidal particles. When the particle size approaches the nanoscale, the curvature of the particles becomes relevant. Here I use a classical density functional theory to study the polymer-mediated interactions between two nanorods. The rods are immersed in an athermal, melt polymer blend consisting of: 1) a small fraction of chains of length N=20 with ?sticky? ends that are attracted to the rods with energy e/kT so that they form a polymer brush on the rods; and 2) a matrix of chains of length P which have no interactions with the rods. The structure of the brushes depends on the nanorod diameter, P, and e/kT. There is an attractive well in the force between the rods near contact, followed by a strong repulsion as the brushes are compressed. The depth of the well increases with increasing P. I will discuss the implications for experimental systems.

Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.