by Professor Oliver G. Schmidt
The creation of 3D micro-and nanoobjects with well-defined and reproducible
functionalities remains a key challenge in nanotechnology. A promising approach
consists in shaping multifunctional nanomembranes into advanced 3D micro- and
nanoarchitectures.1 Planar nanomembranes can be
defined with unrivalled precision by well-established thin film technologies and
lateral patterning techniques on a substrate surface. After deposition and
structuring, the nanomembranes will shape themselves if sufficient built-in
strain is present during release from the substrate .
If this strain is homogeneously distributed over the thickness of the
nanomembrane, it then forms into a network of well defined and ordered
wrinkles,2,3 which show potential
for highly integrative nanofluidic systems with ultra high-speed electronic and
Of particular interest are nanomembranes which curl themselves into rolled-up
micro-/nanotubes driven by a built-in stress gradient across the layer thickness
(Fig. 1(a)). The technology of creating micro-/nanotubes directly on a chip is
entirely disruptive and has no counterpart anywhere else. The approach is fully
integrative with existing technologies since - by definition - the tubes are
fabricated at a well-defined position on a chip.
The tubes are scalable in size from millimeters to nanometers and the
diameter of the tubes are only dependent on layer thicknesses, differential
stress, and elasticity of the materials. This directly implies that the tube
size is decoupled from the lithographic resolution used to define the 2D sheet
to be rolled-up. The choice in materials and its combinations are universal and
they can be deposited as a 2D layer.
While the roll-up of stressed metal films on substrates is a phenomenon known
for more than 100 years,5 it is only a decade ago
that the great potential of this observation was recognized as a major
breakthrough in interdisciplinary nanotechnologies.6
By now, we are able to create micro-/nanotubes out of practically any material
combination, including Si, C, Fe, Au, ZnO, Ag, Pt, SiO2 and
combinations thereof. Naturally, this leads to a manifold of different
applications and concepts, including lab-in-a-tube systems,7 meta-material fiber optics,8
optofluidic components9 and multifunctional
Figure 1 (b,c) shows a jet engine made from a rolled-up multifunctional
nanomembrane, which self-propels in H2O/H2O2.
The inner surface of the tube consists of platinum, which induces a catalytic
reaction leading to oxygen bubble formation inside the tube body. The bubbles
are thrusted out of the tube opening and the engine moves into the opposite
direction by repulsion.
Since we included a Fe layer as a ferromagnetic material into the tube wall,
the direction of the moving jet engine can be controlled by an externally
applied magnetic field (Fig. 2). Such obejcts can be used for drug delivery and
cargo transportation in lab-on-a chip systems or maybe in the far future in
human bodies for desease curing.
1. O. G. Schmidt, N. Schmarje, C. Deneke, C. Müller, and N.-Y.
Jin-Phillipp, "Three-dimensional Nano-objects evolving from a two-dimensional
layer technolog.", Advanced Materials 13, 756 (2001)
2. Y. F.
Mei, D. J. Thurmer, F. Cavallo, S. Kiravittaya, O. G. Schmidt, "Semiconductor
sub-micro-/ nanochannel networks by deterministic layer wrinkling", Advanced
Materials 19, 2124 (2007)
3. A. Malachias, Y. F. Mei, R. K.
Annabattula, Ch. Deneke, P. R. Onck, O. G. Schmidt, "Wrinkled-up nanochannel
networks: Long-range ordering, scalability, and X-ray investigation", ACS Nano
2, 1715 (2008)
4. Y. F. Mei, S. Kiravittaya, M. Benyoucef, D.
J. Thurmer, T. Zander, C. Deneke, F. Cavallo, A. Rastelli, O. G. Schmidt,
"Optical properties of a wrinkled nanomembrane with embeded quantum well", Nano
Letters 7, 1676 (2007)
5. G. G. Stoney, "The Tension of
Metallic Films Deposited by Electrolysis" Proc. R. Soc. Lond. A 82, 172-175
6. O. G. Schmidt and K. Eberl, "Thin solid films roll
up into nanotubes", Nature 410, 168 (2001)
7. G. S. Huang, Y.
F. Mei, D. J. Thurmer, E. Coric, O. G. Schmidt," Rolled-up transparent
microtubes as two-dimensionally confined culture scaffolds of individual yeast
cells", Lab on a Chip 9, 263 (2009)
8. E. J. Smith, Z. Liu, Y.
F. Mei, O. G. Schmidt, "Combined surface plasmon and classical waveguiding
through metamaterial fiber design", Nano Letters 10, 1 (2010)
9. A. Bernardi, S. Kiravittaya, A. Rastelli, R. Songmuang, D. J.
Thurmer, M. Benyoucef, O. G. Schmidt, "On-chip Si/SiOx microtube refractometer",
Applied Physics Letters 93, 094106 (2008)
10. Y. F. Mei, G. S.
Huang, A. A. Solovev, E. Bermúdez Ureña, I. Moench, F. Ding, T. Reindl, R. K. Y.
Fu, P. K. Chu, O. G. Schmidt,"Versatile approach for integrative and
functionalized tubes by strain engineering of nanomembranes on polymers",
Advanced Materials 20, 4085 (2008)
11. A. A. Solovev, Y. F.
Mei, E. Bermúdez Ureña, G. S. Huang, O. G. Schmidt," Catalytic microtubular jet
engines self-propelled by accumulated gas bubbles", small 5, 1688 (2009).
Copyright AZoNano.com, Professor Oliver G. Schmidt