STRUCTURE IN TETHERED CHAINS - POLYMERIC MICELLES AND CHAINS ANCHOREDON POLYSTYRENE LATEX SPHERES

The star models are briefly summarized and used to explain the layer t hickness of the soluble block of polystyrene-poly(ethylene oxide) (PS- PEO) diblock copolymer micelles in water and cyclopentane. Both the di screte blob model (DB) and the distribution density (DD) model describ e well the tethered layer of the soluble block. The structure and thic kness of the adlayer formed by adsorption of the PS-PEO diblock copoly mer micelles onto PS lattices is strongly dependent on the radius of t he latex particle and the length of the PEO block. The star model is a dequate for a latex of 32 nm radius and long PEO blocks (N = 445 and 4 80), but deviates for smaller PEO chains (N = 148), where the adlayer thickness is well predicted by the planar brush model. This planar bru sh model is still valid for a latex of 54 nm radius and the same PEO c hain. For longer chains and/or larger lattices, neither model correctl y predicts the adlayer thickness because of the disruption of the mice lles during their adsorption process. This disruption results in the f ormation of loops and trains on the PS surface that make the subsequen t adsorption of more micelles and the formation of a dense adlayer dif ficult.