Tailoring functionality in materials

David Wang Auditorium, 3rd floor, Dalia Maydan Bldg.
Dr. Maximilian Wolff

Dr. Maximilian Wolff

Department for Physics and Astronomy, Uppsala University, Sweden

Material science has developed tremendously in the last decades and a fundamental understanding is emerging enabling tailor designed materials with very specific functionality. However, exactly predicting macroscopic functionality from the composition, structure and dynamics at the atomic level remains challenging and engineering science, or pharmacy, often rely on screening approaches. The reason for this is the large range of length and time scales that need to be addressed. At one end computer simulations and synthesis is concerned with atomic length and time scales, while mean field approaches and our daily experience cover the macroscopic emergence of functionality.

In this talk I will provide a brief overview on the research activities at the Ångströmlaboratoriet with an emphasis on material physics, followed by a detailed discussion of two research topics:

Polymers: Complex liquids have unique flow properties, which are related to changes in their local structure as well as to the wide spectrum of relaxation times. This gives large flexibility to design their mechanical properties and nowadays polymers are found almost everywhere in our daily live. In this talk I will summarize our recent research investigating viscoelasticity on the microscopic scale. Specific emphasis will be on flow instabilities at the solid boundary and topological interactions. The research aims at a comprehensive understanding of viscoelasticity on all length and time scales.

Magnetic liquids: Similar to Archimedes principle for floating objects in water, a non-magnetic micro beat can behave effectively magnetic when introduced in a ferro-fluid. Following this approach material properties, like e.g. viscosity or electron transport, can be tuned by magnetism and be optimized independently. I will present optical microscopy studies on the phase behavior of such systems and connect them to their electrical performance as switches. These studies are complemented by particle synthesis and the adsorption at model surfaces.

Neutron scattering methods provide a valuable, direct and quantitative approach to extract key information for all the above areas. I will highlight the the complementary results and address some challenges and opportunities connected to the method.