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CPP: Chemische Physik und Polymerphysik

CPP 12: POSTER Colloids, Nanoparticles and Self-Organizing Systems

CPP 12.2: Poster

Dienstag, 28. März 2006, 17:00–19:00, P3

Interaction of a spherical particle with linear chains — •Jaroslaw Klos — Faculty of Physics, A. Mickiewicz Univ., Umultowska 85, 61-614 Poznan, Poland

Linear polymers surrounding a hard sphere are simulated using the Cooperative Motion Algorithm on the face centered cubic lattice. The excluded volume condition is taken into account, and the properties of the chains are examined in two situations of: (i) free polymers, (ii) chains end-grafted onto the spherical surface (No-dqhairy spheresNo-dq). In case (i) the size ratio q=R/Rg of the sphere radius to the mean radius of gyration of the chains is considered the main parameter. The simulations indicate (1) a depletion layer in the neighborhood of the sphere, (2) an enhancement of the chain ends concentration at the particle surface, (3) an enhancement of the chain centers of mass concentration at some distance from the surface for large q, (4) a penetration of the centers of mass into the sphere for small q, (5) an orientation ordering of the chains in the region of interest. In case (ii) the simulations are performed in two extremes of the surrounding matrix: (a) the hairy spheres immersed in a pure solvent of single beads and (b) the hairy spheres in a melt of chains. The simulations indicate that (1) the concentration profiles of the end-grafted chains under good solvent conditions are noticeably different from those calculated for the chains in a melt, (2) as the sphere radius increases, the monomer concentration profile changes from concave to convex (3) both the free ends and the centers of mass profiles are Gaussian-like, (4) depending on the position of the center of mass, both tangential and radial ordering of the polymers relative to the sphere are present.