Dresden 2017 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 68: Hydrogels and Microgels II

CPP 68.7: Talk

Friday, March 24, 2017, 12:00–12:15, ZEU 260

Surface forces of polyelectrolyte multilayers in different growth regimes — •Heba S. Mohamad, Malte Paßvogel, Annkatrin Sill, and Christiane A. Helm — Inst. of Physics, Greifswald University, D-17487 Greifswald

Interaction with the surface of polyelectrolyte multilayer films is important for many application. The films built from Poly (styrenesulfonate) (PSS) and poly (diallylmethylammonium) (PDADMA) in 0.1 Mol/L NaCl start with a parabolic growth regime. Then a transition to linear growth occurs. In the linear growth regime, there are more positive PDADMA than negative PSS monomers in the film; therefore Na¹ ions are incorporated. PDADMA and PSS terminated films in the parabolic growth regime show flat surfaces which interact purely electrostatically, as surface forces measurements with the colloid probe technique show. In the linear growth regime, PSS terminated films are also flat, but PDADMA terminated films interact by steric forces which are analysed with the Alexander-de-Gennes theory. The PDADMA chains protruding into solution are attributed to the excess PDADMA monomers within the film. We conclude that choosing the growth regime allows to control the surface interactions.