PhD ceremony Mr. S. Punzhin: Performance of ordered and disordered nanoporous metals

PhD ceremony: Mr. S. Punzhin, 11.00 uur, Academiegebouw, Broerstraat 5, Groningen

Dissertation: Performance of ordered and disordered nanoporous metals

Promotor(s): prof. J.Th.M. de Hosson

Faculty: Mathematics and Natural Sciences

The research presented in this thesis comes in two parts. The first part focuses on manufacture of and experimentation with metal nanofoams, and the second part focuses on the development of a new and unique experimental technique that permits investigation otherwise not possible.

Nanoporous metal foams are modern and versatile materials with a variety of useful properties. Amongst their many properties is the ability to actuate, i.e. deform in a controllable manner in response to charge injection. Actuation in nanoporous metals occurs when injection of charge into a metal causes a change of surface charge states which leads to measurable deformation. A fascinating question arises on whether an ordered foam microstructure would have a meaningful effect on actuation-based deformation. After all, crystalline metals have preferential directions of deformation and the same principle might apply to an ordered nanoporous metal.

In the second part, we investigate an unexplored and unique technique for nanoporous systems: we coined it Ion-Beam-Induced-Bending (IIB). IIB was shown to have a high accuracy and reproducibility using nothing more than the Focused Ion Beam (FIB) apparatus. It also had the added benefit of requiring no mechanical contact between a deformation apparatus and the sample: under IIB a sample bends due to the influence of the incident ion beam. This unique technique offers the possibility of investigating mechanical response of ordered and disordered metallic nanofoams.