Press release on Tunable critical Casimir forces counteract Casimir-Lifshitz attraction

An illustration of microscopic gold flakes on surface. (Image by F. Schmidt.)
The article Tunable critical Casimir forces counteract Casimir-Lifshitz attraction has been featured in the News of the University of Gothenburg (in English and in Swedish), SISSA-International School of Advanced Studies in Trieste, Italy, Heinrich-Heine-Universität Düsseldorf, and Friedrich-Schiller-Universität Jena.

The study, published in Nature Physics and co-written by researchers at the Soft Matter Lab of the Department of Physics at the University of Gothenburg, demonstrate that tunable repulsive critical Casimir forces can be used to counteract stiction, i.e., the tendency of tiny parts of micro- and nanoelectromechanical devices to stick together, which is caused by the Casimir-Lifshitz interaction.

The study is featured also in Phys.org, NanoWerk.

Here the links to the press releases:
Casimir vs Casimir – using opposing forces to improve nanotechnology (GU, English)
https://www.gu.se/nyheter/casimir-vs-casimir-klaschande-krafter-kan-forbattra-nanotekniken (GU, Swedish)
Casimir vs Casimir – usare forze opposte per migliorare le nanotecnologie (SISSA, Italian)
Casimir vs Casimir – using opposing forces to improve nanotechnology (SISSA, English)
Nano-Bauteile clever voneinander lösen (Heinrich-Heine-Universität Düsseldorf)
Clever method for separating nano-components (Friedrich-Schiller-Universität Jena)
Clever method for separating nano-components (Phys.org)
Clever method for separating nano-components (NanoWerk)

Tunable critical Casimir forces counteract Casimir-Lifshitz attraction published in Nature Physics

Gold flake suspended over a functionalized gold-coated substrate. (Image by F. Schmidt.)
Tunable critical Casimir forces counteract Casimir-Lifshitz attraction
Falko Schmidt, Agnese Callegari, Abdallah Daddi-Moussa-Ider, Battulga Munkhbat, Ruggero Verre, Timur Shegai, Mikael Käll, Hartmut Löwen, Andrea Gambassi and Giovanni Volpe
Nature Physics 19, 271-278 (2023)
arXiv: 2202.10926
doi: 10.1038/s41567-022-01795-6

Casimir forces in quantum electrodynamics emerge between microscopic metallic objects because of the confinement of the vacuum electromagnetic fluctuations occurring even at zero temperature. Their generalization at finite temperature and in material media are referred to as Casimir-Lifshitz forces. These forces are typically attractive, leading to the widespread problem of stiction between the metallic parts of micro- and nanodevices. Recently, repulsive Casimir forces have been experimentally realized but their reliance on specialized materials prevents their dynamic control and thus limits their further applicability. Here, we experimentally demonstrate that repulsive critical Casimir forces, which emerge in a critical binary liquid mixture upon approaching the critical temperature, can be used to actively control microscopic and nanoscopic objects with nanometer precision. We demonstrate this by using critical Casimir forces to prevent the stiction caused by the Casimir-Lifshitz forces. We study a microscopic gold flake above a flat gold-coated substrate immersed in a critical mixture. Far from the critical temperature, stiction occurs because of dominant Casimir-Lifshitz forces. Upon approaching the critical temperature, however, we observe the emergence of repulsive critical Casimir forces that are sufficiently strong to counteract stiction. This experimental demonstration can accelerate the development of micro- and nanodevices by preventing stiction as well as providing active control and precise tunability of the forces acting between their constituent parts.