Regensburg 2016 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 42: Functional materials III: Actuators, sensors and functional devices

MM 42.5: Vortrag

Mittwoch, 9. März 2016, 17:00–17:15, H53

Surface stress charge response of nickel in alkaline solutions — •Chuan Cheng and Jörg Weissmüller — Institut für Werkstoffphysik und Werkstofftechnologie, Technische Universität Hamburg-Harburg, 21073 Hamburg, Germany

Charge induced reversible strain was recently found in nanoporous structured nickel upon cyclic potential triggering in alkaline solutions [1,2]. Different from metallic actuators with clean metal surfaces, the surface of Ni is covered with several nanometers thick Ni(II) passive layer, which can cause reversible volume change during Ni(II)/Ni(III) redox reactions. The situation becomes even more complex as different types of Ni(II) can be formed on Ni surface, which exhibit opposite signed volume change when they are oxidized into Ni(III). In this work, surface stress charge response of Ni in alkaline solutions will be characterized by an in situ electrochemical cell. Ni thin film is sputtered on one side of a Si cantilever. Charge induced surface stress in Ni, which causes bending of the cantilever, was measured by a laser-based setup. The surface stress charge coefficients at both capacitive double layer region and the redox region are obtained. This work will provide a fundamental understanding of Ni based electrochemical actuators.

References:

1. M. Hakamada, S. Matsumura, and M. Mabuchi, Mater. Lett. 70, 132 (2012). 2. C. Cheng and A. H. W. Ngan, ACS Nano 9, 3984 (2015).