Adsorption Properties of Silica towards Poly(Ethylene Oxide) as a Function of pH Studied by Spin-Labelling
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H. Hommel
Poly(ethylene oxide) chains spin labelled at their free end were adsorbed on amorphous silica and put into contact with buffers of different pH. The Electron Paramagnetic Resonance spectrum has a shape very sensitive to the Brownian motion of the free radical and exhibits composite lines characteristic of two environments: loops and tails protruding into solution with a fast motion; trains adsorbed on the solid surface with a restricted motion. Both components were analysed and the rotational correlation times and the two populations of labels were plotted as a function of pH and temperature. The chains are progressively desorbed as both increase due to the weaker hydrogen bounding with the reactive silanol groups present at the surface. Therefore a molecular picture of the chains at the interface can be gained.
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Artikel in diesem Heft
- Determination of the Branching Ratios of CaBr(A2Π1/2,3/2, B2Σ+) Resulting from the Reaction of Ca[4s4p (3PJ)] with CH3Br by Time-Resolved Atomic Emission and Molecular Chemiluminescence Following Pulsed Dye-Laser Excitation of Atomic Calcium
- Densities, Apparent Molar Volumes, and Interaction Parameters for the Monosaccharide (D-Xylose, D-Arabinose, D-Glucose, D-Galactose)–NaBr–Water Systems at 298.15 K
- Oscillatory Reaction of Bromate-Gallic acid. A Calorimetric and Electrometric Study in Aquo-Organic Solvent Media
- Adsorption Properties of Silica towards Poly(Ethylene Oxide) as a Function of pH Studied by Spin-Labelling
- Thermodynamic of Transfer and Preferential Solvation of Antibiotic Cephradine in 1,4-Dioxane-Water Mixtures
- Kinetics and Mechanism of the Homogeneous Oxidation of Quinaldine Red by Hydrogen Peroxide
- Interactions in Sphere Packings
- Book Reviews
