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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 24: Poster Session I

CPP 24.31: Poster

Montag, 16. März 2020, 17:30–19:30, P3

DC and AC conductivity of ultra-thin carbon nanotube/polycation multilayers in air and different aqueous solutions — •Sven Neuber, Peter Nestler, Heiko Ahrens, and Christiane A. Helm — Institute of Physics, University of Greifswald, 17489 Greifswald, Germany

To prepare implants covered by an electrically conductive film it is necessary to control the device surface and properties. Electrically conductive multilayers were built by the layer-by-layer technique, sequential adsorption of oppositely charged chemically modified carbon nanotubes and polycations. Quartz crystal microbalance, atomic force microscopy and ellipsometry measurements were used to determine surface coverage, thickness and roughness on nm-scale. Also, frequency-dependent conductivity (kHz range, DC and AC) measurements at ambient conditions (20°C), at different humidities (r.h. between 0 * 100%) and in physiological solutions were investigated to get an overview of the multilayer capability for cell stimulation. It was found that the electrical conductivity depends on the environment. For PDADMA/CNT films (7 layer pairs) in air a current of 22.4 mA was obtained, in 100 mM NaCl solution 20.8 mA and in deionized water 10.5 mA. Also no phase change occurred during the frequency shift up to 100 kHz, indicating an ohmic behavior. The results are discussed in terms of film swelling, electron conductivity through the film and ionic conductivity through the solution.