[HIGHLIGHTS] The Transducer Science and Technology (TST) group has a history and focus on micro system
Prof. dr. Miko Elwenspoek
technology. The research is highly multidisciplinary, ranging from the millimeter down to the nanometer
“Most interesting and
system aspects. The group works on micro- and nanosystems off the beaten paths offered e.g. through
relevant scientific
foundry processes. Applications are clustered around Sensors, Actuators, Micro- and nanofluidics and
and technological
Probe based data storage. Due to the multidisciplinary nature of our work, strong cooperation exists
problems are such
with other MESA+ groups, but also with groups in- and outside UT, as well as many spin-off companies.
that a multidisciplinary
The recent finding of a simple process to machine particles in the range of 10 nm – 10 μm in the form
approach is absolutely
of tetrahedrons, and the experience we are building up with elastocapillarity triggered interest in the
necessary.”
self assembly to realize complex colloidal crystals and three-dimensional systems.
range, including physical concepts, materials and micro- and nanofabrication technology, as well as
Transducer Science and Technology Elastocapillary fabrication of three-dimensional microstructures We machined low-stress silicon nitride flaps connected by flexible joints to study the self-assembly of the flaps by utilizing elastocapillary forces. While initially flat (fig. a, c) a droplet of a liquid which wets the surfaces of the flaps introduces capillary forces which can be balanced by elastic forces. When the liquid evaporates the force balance leads under the right condition to the self-assembly of three-dimensional micro structures as shown in the fig. (b, c (inset), d) to the right. Our models reproduce neatly the form of the system during evaporation, which allows us to design the compliance of the joints. Residues in the liquid droplet lead to a bond between the touching surfaces which are strong enough to stabilize the final three-dimensional form.
Figure: (a) Some of the planar geometries to be folded into 3D shapes by capillary forces. The left structure shows the elongated geometry corresponding to the 2D model, which was used for the experimental analysis. (b) A SEM picture of this 2D structure after complete folding. (c) SEM pictures of a fivefold structure, forming half a dodecaeder (inset). (d) SEM pictures of a four-fold structure from which a “microbox” is folded. All scale bars correspond to 50 μm.
HIGHLIGHTED PUBLICATION: J. W. van Honschoten, J. W. Berenschot, T. Ondarçuhu, R. G. P. Sanders, J. Sundaram, M. Elwenspoek, N. R. Tas, Elastocapillary fabrication of three-dimensional microstructures, Applied Physics Letters 97 (2010) 014103.
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