Regensburg 2019 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 17: Nanomaterials
MM 17.4: Vortrag
Dienstag, 2. April 2019, 11:00–11:15, H46
Electrosorption in Polypyrrole-Silicon Hybrid Nanopores: Insights from Cyclic Voltammetry and Dilatometry — •Manuel Brinker1, Guido Dittrich1, Pirmin Lakner2, Thomas Keller2, and Patrick Huber1 — 1Technische Universität Hamburg — 2Deutsches Elektronen-Synchrotron DESY
Porous silicon provides a scaffold structure to study confinement effects of soft matter, since the pore diameter, pore length and pore shape can be tuned in a wide range. We investigate the electrosorption of electrolyte anions and the electrochemical behaviour of nanoporous silicon in acidic electrolytes. The silicon-electrolyte interface acts as a capacitor which allows the accumulation of electrolyte anions in a chemical double layer by an applied voltage. The sorption characteristics can be measured by cyclic voltammetry. The surface stresses that emerge in a monolithic porous silicon membrane by electrosorption lead to a macroscopic strain which can be measured in-situ with a dilatometer. Furthermore, we investigate the properties of a functional filling of the electrically conductive polymer polypyrrole (PPy) into nanoporus silicon. We successfully demonstrate the filling of PPy into pores of substantial depth of up to 100 µm. In particular, PPy allows for sensoric and actoric applications for the hybrid system. PPy swells when it is exposed to a voltage in an electrolyte, since ions from the electrolyte are intercalated into the polymer structure and expelled subsequently. The confinement effect of the pores on the swelling can be studied with dilatometry measurements as well and is compared to the nanoporous silicon itself.