College Park, Maryland      June 6 - 10 , 2004

MP24: Characterization of Arborescent Graft Polystyrene Molecules by Small Angle Neutron Scattering

Kai-Chi Lai, Robert M. Briber (Department of Materials Science and Engineering, University of Maryland), Mario Gauthier (Department of Chemistry, Institute for Polymer Research, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada), Seok-Il Yun (Condensed Matter Sciences Division, Oak Ridge National Laboratory)

Arborescent graft polymers (AGP) are polymers resulting from successive cycles of random functionalization and subsequent end-grafting of anionic polymerized chains to form a highly branched polymer molecule. Small Angle Neutron Scattering (SANS) was used to characterize the size and shape of generation 3 and generation 4 polystyrene (PS) based arborescent graft polymers where the final generation of the polymer molecule was composed of deuterated PS. Contrast variation techniques were used to match the solvent to the either the PS core or the deuterated PS shell. A core-shell model was used to fit the SANS data with good success but the scattering length density of the core and shell were found to deviate from that of pure PS and deuterated PS respectively leading to the conclusion that there is some phase mixing between the final generation and the underlying polymer substrate molecule. This is consistent with the random functionalization of substrate prior to end-grafting the final generation.

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