Berlin 2012 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 19: Charged Soft Matter

CPP 19.2: Vortrag

Mittwoch, 28. März 2012, 09:45–10:00, C 243

Weak polyelectrolyte adsorption onto oppositely charged interfaces: planar, cylindrical, and spherical geometries. — •Andrey Cherstvy and Roland Winkler — Institute of Complex Systems, ICS-2/IAS-2, Forschungszentrum Jülich, 52425 Jülich, Germany

We suggest a universal description for weak adsorption of flexible polyelectrolytes (PE) onto oppositely charged planar and curved surfaces [Phys. Chem. Chem. Phys., 13 11686 (2011)]. The analysis is based on the WKB quantum mechanical method for the Green function equation. We provide a unified picture for scaling behavior of the critical characteristics and thickness of adsorbed PE layer formed near the interfaces. We find that curved convex interfaces necessitate much higher surface charge densities to trigger the PE adsorption. Different geometries also yield distinct scaling laws for the critical surface charge density σ^⋆. Namely, at low-salt σ^⋆ scales cubical with the inverse Debye screening length for a plane, quadratic for an adsorbing rod, and linearly for a sphere. These novel scaling trends for PE-rod and PE-sphere adsorption are consistent with the complex formation experiments from P. Dubin lab. Above the adsorption threshold, the thickness of the adsorbed PE layer predicted is consistent with other theoretical models. Our analysis can provide a more realistic description of adsorption of charged biopolymers at biologically-relevant conditions.