What is it about?

We introduce a simple way to use tiny gold flakes as natural probes for studying the hidden forces that hold matter together. When these flakes float in liquid, they spontaneously arrange into tiny cavities that trap light. By following their natural motion, we can directly reveal forces that are normally invisible, including the Casimir interaction, a quantum effect that can now be measured directly, and electrostatic interactions that shape many processes in everyday life.

Featured Image

Why is it important?

This promising platform, called Casimir Self-Assembly (CaSA), is fast, non-invasive, and lets us track the behavior of single flakes within an ensemble. It enables us not only to study the “glue of nature” at the smallest scales but also to measure the zeta potential of individual flakes, a key factor that determines whether particles in liquid remain stable or start to clump together. By making these invisible forces visible, CaSA provides a powerful way to explore the fundamental effects of nature while also enabling the study of challenges such as particle stability that affect everyday life.

Perspectives

Working on this project was a real pleasure. What I enjoyed most was the simplicity of the approach: we let tiny gold flakes float in liquid as natural probes to show us the hidden forces at play. It was fascinating to see that something so small and delicate could reveal interactions that are hard to measure, especially between planar, flat objects. We believe this platform has great potential, and I am excited to see where it will lead us in exploring the fundamental forces of nature and their role in everyday systems.

Michaela Hošková
Chalmers tekniska hogskola

Read the Original

This page is a summary of: Casimir self-assembly: A platform for measuring nanoscale surface interactions in liquids, Proceedings of the National Academy of Sciences, August 2025, Proceedings of the National Academy of Sciences,
DOI: 10.1073/pnas.2505144122.
You can read the full text:

Read

Contributors

The following have contributed to this page