Dresden 2011 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 7: Interfaces and Thin Films II
CPP 7.3: Vortrag
Montag, 14. März 2011, 14:30–14:45, ZEU 114
The Young's Modulus of Polyelectrolyte Multilayer: Influence of Charge Density and Ambient Water Vapours — •Ralf Köhler1,2, Ingo Dönch3, Patrick Ott4, André Laschewski4, and Andreas Fery5 — 1TU Berlin, Dept. Applied Physical Chemistry, 10623 Berlin — 2HZB Berlin, Dept. Soft Matter, 14109 Berlin — 3Max Planck Institute of Colloids and Interfaces, Dept. Interfaces, 14424 Potsdam — 4University of Potsdam, Applied Polymer Chemistry, 14476 Potsdam — 5University of Bayreuth, Physial Chemistry II, 95440 Bayreuth: Germany
Polyelectrolyte Multilayers (PEM) are polymer films, self-assembled by consecutive adsorption of oppositely charged polyions. Our study addresses the impact of the internal interactions in the PEM on the macroscopic mechanical behavior. The strategy is to vary the ionic interactions by using polycations of different charge densities (ChD). Furthermore the internal interactions are modified by changing the water content in the PEM by a systematic variation of the ambient relative humidity (RH). PEM of sub-micrometer thickness are prepared in Layer-by-Layer spraying technique on flexible sheets of silicone-rubber. The used polyions are PSS and PDADMAC-derivatives of different ChD. The E-modules are determined with the SIEBIMM-method. We obtained E-Moduli in the range from 0.3 to ca 1.5MPa. Basically for a higher-ChD PEM the E-Modulus is higher. But with increasing RH the PEMs soften until their E-Moduli coincide. Apparently the ionic interactions rule the mechanics in the first place but the incorporated water is able to moderate the E-Moduli over a wide range.