Monte Carlo study of chain conformations in the swollen middle layer of onion-skin polymeric micelles

Conformations of chains in swollen middle layers of onion-skin micelles wer e studied by Monte Carlo simulations on a tetrahedral lattice under conditi ons that mimic real systems of swollen onion-skin micelles. Polymer blocks are modeled as tethered self-avoiding chains, enclosed in a narrow spherica l layer. Average density of segments, [g(S)] ca. 0.6, corresponds to swolle n micellar systems. Only the excluded volume effect was taken into account since it plays the most important role in dense polymer systems. Individual chains are described by equivalent ellipsoids of gyration. Distributions o f the ellipsoid half-axes were calculated during simulations. Results based on a large series of simulations indicate that the middle layer-forming bl ocks may be described as prolonged ellipsoids oriented preferentially perpe ndicular to the radial direction. Analysis of the data concerning the orien tations of end-to-end vectors and distributions of segments within one chai n indicates that individual chains are strongly interpenetrated and the mul ti-chain system is fairly disordered.