Regensburg 2016 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 17: Polyelectrolytes
CPP 17.4: Vortrag
Dienstag, 8. März 2016, 10:30–10:45, H40
Effect of Binary Polymer Mixtures on the Growth of Polyelectrolyte Multilayers (PEMs) — •Malte Paßvogel1, Peter Nestler1, Ralf Köhler2, Olaf Soltwedel3, and Christiane A. Helm1 — 1Inst. for Physics, Uni Greifswald, 17487 Greifswald, Germany — 2Helmholtz-Zentrum Berlin, 14109 Berlin, Germany — 3MPI for Solid State Research, Outstation at FRM-II, 85747 Garching, Germany
Non-linear growth regimes of electrostatically assembled PEMs are investigated with in-situ ellipsometry. Poly(styrene sulfonate) (PSS) and poly(diallylmethylammonium) (PDADMA) are used (cNaCl=0.1 mol/L). Always, linear growth is preceded by a parabolic growth regime. For films of binary PDADMA mixtures, the composition in the film appears to be the same as in the adsorption solution. If PSS molecular weight (Mw) is below a threshold, 25 kDa, film build-up starts with an exponential growth regime, and pronounced PSS interdiffusion is found with neutron reflectivity using deuterated PSSd. 0.5 mol % PSS with high Mw in the adsorption solution prevents exponential growth. Neutron reflectivity shows no vertical center of mass movement of PSS with Mw above the threshold, both in the parabolic and the linear growth regimes. We suggest that polyelectrolytes (PEs) with high Mw adsorb with trains, tails and loops, while PEs with Mw below the threshold adsorb with one train and one tail only.