Not quite solid, but not really liquid either: viscous fluids are commonly found in cosmetics, washing products or paints. They possess a combination of liquid and solid-like properties. Although we use some of these products every day, we know surprisingly little about how they flow.

At the physics department at the University of Fribourg, a research group led by Professor Frank Scheffold has recently reached two milestones in its work on these fluids with strange properties. The Unifr group studied the case of fluids containing tiny globules known as polymer nanoparticles. They showed that, under pressure, these nanoparticles partly penetrate into each other, thus making the fluid behave in strange ways. They have now reported this finding in the well-regarded review Nature Communications.

The same team has obtained funding as part of the “Japanese-Swiss science and technology programme”, with a view to developing new methods to measure the flow properties of unusual fluids. The collaboration combines the expertise of the Unifr group on materials and soft matter physics with the equipment and technical prowess of Professor Amy Shen's micro/bio/nanofluidics Unit at the Okinawa Institute of Science and Technology in southern Japan.

Links:

- Prof. Scheffold group

- Prof. Shen webpage

- Nature Communications paper

- Japan-Swiss sciences and technology programme - a joint programme between the the Swiss National Science Fund and the Japanese Society for the Promotion of Science