Dresden 2009 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 9: Nanoparticles II
CPP 9.7: Vortrag
Montag, 23. März 2009, 15:45–16:00, ZEU 114
Enwrapping of tubular J-aggregates by Polyelectrolytes — •Omar Al-Khatib1,2, Helmuth Möhwald1, Jürgen P Rabe2, Christoph Böttcher3, and Stefan Kirstein2 — 1Max-Planck-Insitut of Colloids and Interfaces, Potsdam, Germany — 2Humboldt University Berlin, Department of Physics, Germany — 3Free University Berlin, Germany
Amphiphilic carbocyanine dyes are able to form tubular J-aggregates in aqueous solutions by a self-assembly process. The wall of the tubular aggregates is assumed to be formed by a dye bilayer that encloses the hydrophobic alkyl chains and exposes negative surface charges to the inside and outside of the aggregates. The charged surface is utilized to adsorb oppositely charged polyelectrolytes in order to enwrap the aggregate. This mechanism allows further stabilization and even functionalization using polyelectrolytes with functional groups. We show the coating of negatively charged tubular J-aggregates by various polycations such as poly(diallyldimethylammonium chloride) (PDAC), poly(allylamine hydrochloride) (PAH), and poly(ethylene imine) (PEI). The enwrapping was verified by cryogenic transmission electron microscopy (cryo-TEM) and its influence on the optical spectra was investigated. The morphology and the optical spectra of the coated structures vary considerably for the different polyelectrolytes and strongly depend on the ionic strength of the solution. The detailed investigation of these parameters allows to find controlled conditions for the formation of complex functionalized structures in aqueous solution by pure self assembling processes.