Canopy Dynamics in a Nanoscale Ionic Material

ORAL

Abstract

We have used nuclear magnetic resonance (NMR) relaxation and pulsed-gradient diffusion measurements to characterize molecular mobility in a set of nanoscale ionic materials (NIMS). 18 nm core silica nanoparticles were functionalized with a covalently attached alkyl silane monolayer corona followed by an ionically tethered bulky ethylene oxide/propylene oxide block copolymer canopy. NIMS are organic-inorganic hybrids exhibiting liquid-like character under ambient conditions in the absence of solvent and are of interest for a variety of applications. Our NMR studies show that the fast (ns) local dynamics of the block copolymer canopy are insensitive to the presence of the silica nanoparticles. Canopy diffusion in the NIMS is only modestly slowed relative to the neat copolymer. Not all canopy molecules are slowed equally due to crowding at the corona-coated nanoparticle surface, resulting in strongly bound fraction at the surface and weakly bound outer sphere capable of rapid exchange of canopy molecules between host particles. Electrostatic interactions with other ionic (Na$^{+})$ species alter the dynamics by decreasing the strongly-bound population.

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Authors

  • E. von Meerwall

    The University of Akron

  • Dale Igram

    Cornell University, Air Force Research Labs, The Center for Photochemical Sciences and Department of Physics, BGSU, Department of Physics, BGSU, Department of Physics and Astronomy, Ball State University, Miami University, Johannes-Gutenberg-Universitat, Mainz, Germany, Martin-Luther-Universitat, Halle, Germany, The Ohio State University, Department of Physics, Columbus, OH 43210, USA, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA, Ohio Northern University, The Ohio State University, Department of Physics, Columbus, OH 43210, Sciprint.org, Ball State University, Department of Physics and Materials Research Institute, Pennsylvania State University, University Park, PA 16802

  • Dale Igram

    Cornell University, Air Force Research Labs, The Center for Photochemical Sciences and Department of Physics, BGSU, Department of Physics, BGSU, Department of Physics and Astronomy, Ball State University, Miami University, Johannes-Gutenberg-Universitat, Mainz, Germany, Martin-Luther-Universitat, Halle, Germany, The Ohio State University, Department of Physics, Columbus, OH 43210, USA, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA, Ohio Northern University, The Ohio State University, Department of Physics, Columbus, OH 43210, Sciprint.org, Ball State University, Department of Physics and Materials Research Institute, Pennsylvania State University, University Park, PA 16802

  • Dale Igram

    Cornell University, Air Force Research Labs, The Center for Photochemical Sciences and Department of Physics, BGSU, Department of Physics, BGSU, Department of Physics and Astronomy, Ball State University, Miami University, Johannes-Gutenberg-Universitat, Mainz, Germany, Martin-Luther-Universitat, Halle, Germany, The Ohio State University, Department of Physics, Columbus, OH 43210, USA, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA, Ohio Northern University, The Ohio State University, Department of Physics, Columbus, OH 43210, Sciprint.org, Ball State University, Department of Physics and Materials Research Institute, Pennsylvania State University, University Park, PA 16802

  • Dale Igram

    Cornell University, Air Force Research Labs, The Center for Photochemical Sciences and Department of Physics, BGSU, Department of Physics, BGSU, Department of Physics and Astronomy, Ball State University, Miami University, Johannes-Gutenberg-Universitat, Mainz, Germany, Martin-Luther-Universitat, Halle, Germany, The Ohio State University, Department of Physics, Columbus, OH 43210, USA, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA, Ohio Northern University, The Ohio State University, Department of Physics, Columbus, OH 43210, Sciprint.org, Ball State University, Department of Physics and Materials Research Institute, Pennsylvania State University, University Park, PA 16802

  • Dale Igram

    Cornell University, Air Force Research Labs, The Center for Photochemical Sciences and Department of Physics, BGSU, Department of Physics, BGSU, Department of Physics and Astronomy, Ball State University, Miami University, Johannes-Gutenberg-Universitat, Mainz, Germany, Martin-Luther-Universitat, Halle, Germany, The Ohio State University, Department of Physics, Columbus, OH 43210, USA, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA, Ohio Northern University, The Ohio State University, Department of Physics, Columbus, OH 43210, Sciprint.org, Ball State University, Department of Physics and Materials Research Institute, Pennsylvania State University, University Park, PA 16802