Regensburg 2016 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 17: Polyelectrolytes
CPP 17.2: Vortrag
Dienstag, 8. März 2016, 10:00–10:15, H40
Long-ranged steric forces between physisorbed polyethylenimine-iron complexes — •Heba S. Mohamad, Heiko Ahrens, and Christiane A. Helm — Inst. for Physics, Uni Greifswald, 17487 Greifswald, Germany
The conformation of branched polyethylenimine (PEI) layers physisorbed from 1 mM Fe2SO4 solution is determined by force measurements. The colloidal probe technique (CPT) is used. PEI adsorbs flatly as purely electrostatic forces indicate. Additon of EDTA to the adsorption solution leads in pure water to steric forces as predicted for neutral grafted brushes. On addition of NaCl to the solution, the grafting density remains constant, yet the brush thickness shrinks and swells reversibly with the NaCl concentration.
X-ray reflectivity demonstrates that iron(II) is incorporated in the adsorbed polyethylenimine-iron complexes. Iron(ii) can be washed from the adsorbed complex without removing the PEI. Adsorption of gold nanoparticles (AuNP) onto a PEI layer with chains protruding into solution leads to an increased AuNP coverage compared to flat positvely charged surfaces.