Self-assembly of metallic MEMS using Casimir forces: Fabrication, simulation and characterization
H. Hillmer · B. Elsaka · P. Kästner · S. Akhundzada · M. K. Hasan · J. Fiedler · S. Y. Buhmann · C. Backes · J. Adam
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In one page
Most writing about the Casimir force treats it as something to measure. Hendrik Hillmer’s group at the University of Kassel, with Johannes Fiedler at Bergen and Stefan Yoshi Buhmann on the theory, use it instead as a tool for building. Their devices are metallic MEMS shutter blades — tiny metal flaps patterned on a chip and then set free by dissolving the sacrificial layer beneath them. As the chip goes through a sequential drying process, surface tension first draws neighbouring blades very close together; at that separation the Casimir force and van der Waals forces take over and hold the blades tightly attached, pairing them into interlocking Yin- and Yang-shaped structures. The outcome is genuine three-dimensional structure assembled out of a flat chip by the forces of the quantum vacuum rather than by any tool. The team also reports what happened when they tried to prise the pairs open again, and how the balance between the fundamental forces shifts as the system is scaled.
Why it matters hereChapter 2 argues that the vacuum is a real medium with real forces, and this is the version of that claim with the fewest steps in it: at these separations the Casimir force is not a delicate signal but construction equipment, strong enough to hold metal parts shut. Chapter 6 gets the engineering lesson that every vacuum-energy device runs into — vacuum forces move real hardware at real length scales, and the hard part is releasing what they have grabbed.
What it claims
01A methodology of three-dimensional self-assembly is presented, pairing neighbouring microelectromechanical system elements to create Yin- or Yang-shaped structures. The structure is not machined into place; it forms itself out of a planar chip.Abstract, first sentence
Published and peer-reviewed02The mechanism is reported in two stages. After sacrificial layer removal and during the sequential drying process, surface tension forces bring the neighbouring MEMS shutter blades very close to each other; then Casimir forces and van der Waals forces keep the blades attached tightly. Surface tension does the approach, the vacuum forces do the holding.Abstract, second sentence
Published and peer-reviewed03The attachment is strong enough that undoing it is itself an experiment: the authors report various experimental trials to reopen the tight attachments. A force normally discussed in micronewtons and nanometres is here a fastening that resists deliberate attempts to release it.Abstract, third sentence
Published and peer-reviewed04The paper presents the relative significance of fundamental forces during one-dimensional and three-dimensional scaling of the system — that is, an account of which force takes over at which size as the device shrinks. This is the practical form of the question chapter 2 asks about the vacuum, and it is answered here with fabricated hardware, simulation and characterisation together.Abstract, final sentence; article title
Published and peer-reviewed05What to watch is release on demand. Self-assembly that closes once is a fabrication technique; the same blades opened and closed under control would be a Casimir-driven actuator, and the paper’s reopening trials are the first measurement on that path. The result to look for is a reported energy or voltage that reliably separates an attached pair without damaging it.Abstract, third sentence
What to watch
The way in
https://doi.org/10.1142/S0217751X2543016XPublished in the International Journal of Modern Physics A, volume 40, issue 10n11, online 26 February 2025. Eight of the nine authors are at the Center for Interdisciplinary Nanostructure Science and Technology at the University of Kassel — the Institute of Nanostructure Technologies and Analytics, the Institute of Physics, the Institute of Chemistry and the Computational Materials and Photonics group — with J. Fiedler at the Department of Physics and Technology, University of Bergen. The article is closed access: OpenAlex and Unpaywall both report no open copy and no licence, no arXiv preprint was found by author or title search, and the World Scientific page returns a bot challenge rather than the text. The full text was therefore NOT read. This sheet was written on 2026-09-08 from the authors’ own abstract as deposited with Crossref, together with the bibliographic record; every claim below is drawn from that abstract alone and located to it. No text is reproduced here.
How to cite it
H. Hillmer, B. Elsaka, P. Kästner, S. Akhundzada, M. K. Hasan, J. Fiedler, S. Y. Buhmann, C. Backes, J. Adam (2025) Self-assembly of metallic MEMS using Casimir forces: Fabrication, simulation and characterization. doi:10.1142/S0217751X2543016X
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