Berlin 2012 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 8: Poster: Nanoparticles and Composite Materials

CPP 8.37: Poster

Montag, 26. März 2012, 17:30–20:00, Poster A

Förster resonance energy transfer (FRET) experiments on tubular J-aggregates wrapped with dye labeled polyelectrolytes — •Omar Al-Khatib¹, Christoph Böttcher², Hans von Berlepsch², Jürgen P. Rabe¹, and Stefan Kirstein¹ — ¹HU Berlin, Inst. für Physik Newtonstr. 15, 12489 Berlin — ²FU Berlin, Forschungszentrum für Elektronenmikroskopie, Fabeckstr. 36a, 14195 Berlin

In this contribution we demonstrate the coating of tubular J-aggregates with dye-labeled polyelectrolytes. The tubular J-aggregates are formed by an amphiphilic cyanine dye in aqueous solutions [1]. These aggregates can be considered as cylindrical objects with 13 nm diameter, length exceeding microns and a negative surface potential. It is shown by cryogenic electron microscopy (cryo-TEM) that polycations can be adsorbed at the aggregate surface forming a homogeneous coating layer. Poly(diallyldimethyl ammonium chloride) (PDAC) and poly(allylamine hydrochloride) (PAH) labelled with different fluorescent dyes are used, acting as donors or acceptors within a Förster energy transfer (FRET) process. The donor and acceptor dyes are distributed homogeneously within the coating. The FRET is investigated by static optical absorption and fluorescence spectroscopy. The experiments demonstrate the possibility for symmetric energy transfer from donors to the aggregate and from the aggregate to acceptors. No indication for enhanced energy transfer due to exciton diffusion was found. [1] D.M. Eisele, et al., Nature Nanotech. 4 (2009) 658;