Berlin 2008 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 21: POSTERS Colloids, Nanoparticles and Aggregates

CPP 21.5: Poster

Mittwoch, 27. Februar 2008, 16:00–18:30, Poster A

Polyelectrolyte coating of tubular J-aggregates investigated by cryo-TEM — •Omar Al-Khatib¹, Dörthe M. Eisele², Jürgen P. Rabe², Christoph Böttcher³, and Stefan Kirstein² — ¹MPI-Golm, Inst. für Kolloid- und Grenzflächenforschung, Wissenschaftspark Golm, 14424 Potsdam — ²HU-Berlin, Inst. für Physik, Newtonstr. 15, 12489 Berlin — ³FU-Berlin, Forschungszentrum für Elektronenmikroskopie, Fabeckstr. 36a, 14195 Berlin

Amphiphilic carbocyanine dyes are able to form tubular J-aggregates in aqueous solutions by a self-assembly process [1]. The wall of the tubular aggregates is formed by a dye bilayer that encloses the hydrophobic alkyl chains and exposes negative surface charges to the water. The charged surface is utilized to adsorb oppositely charged polyelectrolytes in order to cover the aggregates by the polymer and gain mechanical stabilization and further functionalization. The addition of various polycations such as poly(diallyldimethylammonium chloride) (PDAC) and poly(allylamine hydrochloride) (PAH) was investigated by optical spectroscopy and cryogenic transmission electron microscopy (cryo-TEM). It is found that the relative concentration of the polyelectrolyte is a critical parameter for precipitation of the structures. This and other solvent conditions and their influence on the spectra and structure are discussed.

[1]S.Kirstein, S. Dähne, International Journal of Photoenergy, Volume 2006, Article ID 20363, 1-21