Dresden 2014 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 54: Poster Session 3
CPP 54.25: Poster
Donnerstag, 3. April 2014, 15:00–19:00, P2
Influence of Polycation Molecular Weight and Diffusion Barriers on Interdiffusion in Polyelectrolyte Mulitlayers — •Peter Nestler1, Malte Paßvogel1, Olaf Soltwedel2, Heiko Ahrens1, Ralf Köhler3, and Christiane A. Helm1 — 1Inst. f. Physik, Uni Greifswald, 17487 Greifswald, Germany — 2MPI für Festkörperforschung, 70569 Stuttgart, Germany — 3Inst. of Soft Matter and Functional Materials, HZB, Berlin, Germany
After introduction of the Layer-by-Layer technique (LbL) twenty years ago, surfaces were modified by covering them with thin films of different composition. A wide variety of potential applications for polyelectrolyte multilayers (PEM) is known, for example chemical reactors, or microcontainers. For these films, it is important to know how interdiffusion due to external stimuli changes the internal film structure.
PEMs are made from poly(diallyldimethylammonium) (PDADMA), poly(styrenesulfonate) (PSS), and deuterated PSS-d. Each film consists of a protonated and a deuterated compartment. The films are annealed in 1 M NaCl and investigated with neutron reflectivity. During annealing the internal interface between both departments broadens due to interdiffusion.
A branched polycation layer (PEI) in the film centre serves as a diffusion barrier, and the diffusion constant through the barrier decreases monotonically with PDADMA molecular weight. Without the PEI diffusion barrier, PSS diffuses one to two orders of magnitude faster.