Regensburg 2016 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 26: Poster: Charged Soft Matter, Polyelectrolytes, Ionic Liquids
CPP 26.9: Poster
Dienstag, 8. März 2016, 18:15–21:00, Poster B2
Branched Poly(ethylenimine) as Barrier Layer for Polyelectrolyte Diffusion in Multilayer Films — Peter Nestler1, Malte Paßvogel1, •Heiko Ahrens1, Olaf Soltwedel2, Ralf Köhler3, and Christiane A. Helm1 — 1University Greifswald, 17487 Greifswald, Germany — 2MPI for Solid State Research, 70569 Stuttgart, Germany — 3HZB, 14109 Berlin, Germany
Polyelectrolyte multilayer films are made by sequential adsorption of polyanions and polycations from 0.1 mol/L NaCl. Their internal structure is investigated with neutron reflectivity. The films are made from poly(ethylenimine) (PEI), poly(diallyldimethylammonium) (PDADMA) and poly(styrenesulfonate) (PSS respective deuterated PSSd). Each film consists of a protonated and a deuterated block, built from m protonated and n deuterated polycation/polyanion layer pairs, respectively. The films are annealed in salt solution (1 mol/L NaCl). During annealing of PDADMA/PSS films the internal interface between the two blocks broadens due to interdiffusion, thus the PSS diffusion coefficient is measured. Eventually the annealing leads to a uniform distribution of protonated and deuterated PSS throughout the PDADMA/PSS film. Yet, if one polycation layer in the film centre is branched PEI, then this PEI layer serves as a diffusion barrier, which is impenetrable for up to a third of PSS. The equilibration time of the remaining mobile PSS fraction increases which is attributed to the low permeation rate through the barrier layer. Possibly, some PSS molecules have a conformation that hinders them to cross the barrier layer, or the barrier layer gets clogged with time.