Dresden 2011 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 7: Interfaces and Thin Films II
CPP 7.5: Vortrag
Montag, 14. März 2011, 15:00–15:15, ZEU 114
Interdiffusion in Polyelectrolyte Multilayers during Film Formation — •Olaf Soltwedel1, Oxana Ivanova1, Peter Nestler1, Ralf Köhler2,3, and Christiane A. Helm1 — 1Inst. für Physik, Uni Greifswald, Felix-Hausdorff-Str. 6, D-17487 Greifswald — 2Helmholtz-Zentrum für Materialien und Energien, Hahn-Meitner-Platz 1, D-14109 Berlin — 3Stranski-Laboratorium für Physikalische und Theoretische Chemie, TU Berlin, Strasse des 17. Juni 112, D-10623 Berlin
Using neutron reflectivity, the internal structure of polyelectrolyte multilayers is described on the nanoscale. The polyanion is poly(styrenesulfonate) (PSS), and the polycation is poly(allylamine hydrochloride) (PAH) or poly(diallyldimethylammonium chloride) (PDADMAC). Each film consists of a protonated and a deuterated block, built from x protonated and y deuterated polycation/polyanion bilayers, respectively. The number of bilayers N = x + y is kept constant; the position of the interface between the blocks is varied systematically. The internal roughness is smallest next to the film/air interface and increases with the number of bilayers away from the film/air interface until an equilibrium value is reached. For PDAMAC/PSS films, the diffusion constant increases with the PDADMAC polymer length, therefore the interdiffusion is attributed to stress relaxation during deposition. The equilibrium internal roughness increases with PDADMAC polymer length and the salt concentration in the deposition solution. However, the number of polyanion/polycation layer pairs necessary to achieve the equilibrium internal roughness depends nonmonotonically on the salt concentration.