Thermal Stability and Mechanical Properties of Hierarchical Core-shell Structures

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PhD. Candidate Mr. Ehud Almog




Architected hierarchical materials design allows tailoring the bulk properties of a large object by modifying the smallest nano-size constituents. The unique properties can be adjusted to specific applications by choosing the suitable architecture and constituent material, opening endless possibilities for the design of new materials. In this work, we combined several fabrication techniques and synthesized core-shell hierarchical structures of two types: naturally grown free-standing salt whiskers coated with thin nanocrystalline Au film, and polymer-platinum nanolattices. The KCl whiskers were grown on a porous substrate, resulting in single-crystalline high aspect ratio whiskers. They were then coated with a thin Au layer. This simple core-shell structure allowed us to investigate the thermal stability of the film with the emphasis on the three-dimensional features of the core-shell structure such as corners and edges. To extend our study to more complex architecture and large-scale hierarchy, we designed polymeric nanolattice by CAD and fabricated them using a two photon lithography technique. The lattices were then coated with a thin film of platinum using the ALD method. The interaction of the gaseous ALD precursor with the polymer surface resulted in a porous film with nanograins, providing a hierarchy ranging from the micrometer-sized overall dimensions down to the microstructural features of a few nanometers. In-situ compression of the nanolattices revealed that microstructure evolution during deposition has a significant impact on the overall structural behavior.

Supervisor: Prof. Eugen Rabkin

The lecture will take place in room 302, Meidan, for green pass holders, or via ZOOM.

Meeting ID: 995 9239 6977

Passcode: mt302m