Dr. Sebastian Bohm from the TU Ilmenau has won first prize in the NanObjectives University photo competition with his fascinating photo of a micropump. The physicist developed the "E-PunCh" pump - short for "Electrowetting Pump on a Chip" - for his doctoral thesis, for which he was recently awarded the highest distinction of summa cum laude. Today, Sebastian Bohm lives two great passions: science and research and photography.
What is more fascinating: the photos of the micropump or the E-PunCh pump itself? The pump, manufactured on a silicon wafer and only about half a millimeter high, is able to move liquids with high precision - and completely without moving parts, using only electrical voltage. Instead of mechanical pistons or membranes, the liquid itself does the pumping work. Sebastian Bohm developed the innovative micropump system as part of his dissertation at the Group Theoretical Physics I at TU Ilmenau in collaboration with 5microns GmbH, an Ilmenau-based high-tech company that develops and manufactures customer-specific microsystems and processes. The production took place in the clean rooms of the Center for Microand Nanotechnologies at the TU Ilmenau - one of the largest clean rooms of any university in Europe. The E-PunCh micropump, which precisely dispenses the smallest quantities of liquid, can be used in a wide range of applications: In medical technology, for example, in automatic drop dispensers, in insulin pumps and in pipetting robots, or in the food industry, for example - wherever precise dosing and low production costs are required at the same time. In his doctoral thesis, Sebastian Bohm also developed numerical methods that can be used to describe the behavior of liquids in microfluidic systems under the influence of electric fields. Professor Erich Runge, Head of the Group Theoretical Physics I, who supervised the dissertation, is delighted with its high scientific standard: "I have not seen such a double talent, who is at the forefront of microsystems technology and theoretical physics worldwide, even at Harvard."
By winning first prize in the NanObjectives competition at TU Ilmenau, 32-year-old Sebastian Bohm has demonstrated his photographic talent in addition to his outstanding skills as a young scientist. His photo beat off competition from over 50 creative research and technology entries from scientists and students at TU Ilmenau. He captures half of a tiny micropump - pump chamber and valves - in dazzling colors. To do this, Sebastian Bohm precisely placed five drops of water in the pump chamber, each with a volume of around one microliter, or one millionth of a liter! He had previously hydrophobized the surface of the silicon wafer, i.e. treated it to make it water-repellent: he coated the substrate with a layer of a polymer that was only a few nanometres, a few millionths of a millimetre, thick. This allowed the water droplets to settle on the surface without running onto it. The resulting image is made up of 170 individual images, which Sebastian Bohm combined using focus stacking, a special recording and image processing technique, to create a single image with an exceptionally high depth of field. To create the different colors in the drops, the bluish background light and the reflections in the drops of water, he changed the color of the LED lighting after every 60 images. The result: a fascinating view of a micro-world that would otherwise remain hidden from the human eye.
Sebastian Bohm is now a research assistant in the group of his doctoral supervisor Professor Erich Runge and a development engineer at 5microns GmbH. From October, he will continue his research in the field of fluidics as a postdoc at Chalmers University of Technology in Gothenburg. In the meantime, the E-PunCh pump has already been patented. As for his passion for photography, he says: "Photography is an exciting hobby for me, as it requires both technical understanding and creative imagination. Similar to physics and microsystems technology, this results in a special combination of precision and creativity."
