Robotic Instruments

Prof. Quan Zhou

Leader of the research group

Email: firstname.lastname [at] aalto [dot] fi
Telephone: + 358 40 855 0311
Address: Maarintie 8, 02150 Espoo, Finland
Office: TUAS building, 3570

Acoustic manipulation

We have clarified the myth of motion randomness of particles on vibrating plate before they settles to nodal lines since the original experiments of Ernst Chladni in 1780s, and invented a multi-particle single actuator acoustic manipulation method. In contrary to many potential-trapping based acoustic manipulation methods, our technology is based on the out-of-nodal-line motion. 

By repeatedly measuring the position of objects and playing a selected musical note, our method allows independent trajectory following, pattern transformation, and sorting of multiple miniature objects in a wide range of materials, including electronic components, water droplets loaded on solid carriers, plant seeds, candy balls, and metal parts.

Selected publications:

• Controlling the motion of multiple objects on a Chladni plate, Q. Zhou, V. Sariola, K. Latifi, V. Liimatainen, Nature Communications 7, 12764, 2016.

Video: youtube

Wetting and microfluidics

We have invented Scanning Droplet Adhesion Microscopy (SDAM) to measure the fine wetting details of water repellent surfaces. SDAM does not require a direct line of sight, allowing measurement of uneven surfaces such as fabrics or biological surfaces. It is extremely sensitive and 1000 times more precise than the previous wetting characterization methods. In addition, it can detect wetting properties of microscopic functional features that were previously very difficult to measure.

We have designed methods to control liquid spreading using simple silicon undercut structures, which can confine the wetting of liquids even with very low surface tension.

We have also discovered that the electron beam of environmental scanning electron microscope (ESEM) can create precise patterns that have extreme wetting contrast of 150º and features as small as 1 µm.

We also applied the hydrophilic-superhydrophobic patterns for gravity induced rapid deposition of nano-liter droplets.

Selected publications:

• Mapping microscale wetting variations on biological and synthetic water-repellent surfaces, V. Liimatainen, M. Vuckovac, V. Jokinen, V. Sariola, M.J. Hokkanen, Q. Zhou & R.H.A. Ras, Nature Communications 8, 1798, 2017. 
• Controlling liquid spreading using microfabricated undercut edges, V. Liimatainen, V. Sariola, Q. Zhou, Advanced Materials 25 (16), 2275-2278, 2013.
• Maskless, High‐Precision, Persistent, and Extreme Wetting‐Contrast Patterning in an Environmental Scanning Electron Microscope, V. Liimatainen, A. Shah, L.S. Johansson, N. Houbenov, Q. Zhou, Small 12 (14), 1847-1853, 2016.
• Sliding droplets on hydrophilic/superhydrophobic patterned surfaces for liquid deposition, B. Chang, Q. Zhou, R.H.A. Ras, A. Shah, Z. Wu, K. Hjort, Applied Physics Letters 108 (15), 154102, 2016.

Surface-tension assisted hybrid microassembly

We have conducted extensive research on surface-tension assisted hybrid microassembly, including the first extensive study of how self-alignment and robotic pick-and-place can work together, how different process parameters, including surface chemical properties, topographical features, fabrication precision, and material softness, affect the surface-tension driven (or capillary) self-alignment.

The work has also been applied to integration of semiconductor chips, laser diodes, and 3D integration of microchips, especially in the EU FP7 project FAB2ASM where Prof. Zhou was the coordinator.

Selected publications:

• Hybrid microassembly combining robotics and water droplet self-alignment, V. Sariola, M. Jääskeläinen, Q. Zhou, IEEE transactions on robotics 26 (6), 965-977, 2010.
• Self-transport and self-alignment of microchips using microscopic rain, B. Chang, A. Shah, Q. Zhou, R.H.A. Ras, K. Hjort, Scientific reports 5, 2015.
• Surface tension-driven self-alignment of microchips on low-precision receptors, I. Routa, B. Chang, A. Shah, Q. Zhou, Journal of Microelectromechanical Systems 23 (4), 819-828, 2014.
• Capillary-driven self-assembly of microchips on oleophilic/oleophobic patterned surface using adhesive droplet in ambient air, B. Chang, V. Sariola, S. Aura, R.H.A. Ras, M. Klonner, H. Lipsanen, Q. Zhou, Applied Physics Letters 99 (3), 034104, 2011.
• Capillary Self-Alignment of Microchips on Soft Substrates,
  B. Chang, Q. Zhou, Z. Wu, Z. Liu, R.H.A. Ras, K. Hjort, Micromachines 7 (3), 41, 2016.

Micromanipulation using robotic electromagnetic needle

We have developed robotic eletromagnetic needle for selective picking and precise manipulation of magnetic microparticles in liquid medium. We control precisely the magnetic field at the micro sharp needle tip to allow picking of single magnetic microparticles in a population, and can place multiple magnetic microparticles at precise locations or one against another.

Selected publications:

• Manipulating Superparamagnetic Microparticles with an Electromagnetic Needle, Z. Cenev, H. Zhang, V. Sariola, A. Rahikkala, D. Liu, H.A. Santos, Q Zhou, Advanced Materials Technologies, 2017.