Anwendung und Analyse der Impedanzspektroskopie in Electrowetting-Lab-on-Chip Systemen

Stefan Clara

Research output: ThesisMaster's / Diploma thesis

Abstract

The thesis describes a Lab on Chip (LOC) System. This is the attempt to miniaturise the functionality of a chemistry laboratory and to integrate it on a chip. With this reduction in size similar advantages as with the semiconductor IC are to be expected, this means: -> Cheaper fabrication because of mass production. -> Cost reduction through less reagents. -> Time savings with the help of parallelisation. Additionally, completely new opportunities are possible through miniaturisation because of the replacement of the volume forces by the surface forces. The physical laws behind this can be illustrated easily: If L is the characteristic length of a system, then the volume forces FV are proportional to L^3, the surface forces FO on the other hand are proportional to L^2. For small values of L the surface forces dominate. Because of these changes the LOC systems also allow other application areas like disposable analysers, mobile test devices and quicker tests. The thesis is divided into four sections: -> The first and second part refers to electrowetting systems (EWOD), that is, the movement of droplets on special electrodes. In The first part: In this section a digital microfluidic concept that operates with electrostatic forces is presented. The basic operations like moving, creating, dividing and mixing have to work reliably to get flexible electrowetting systems. With these operations it is possible to handle many chemical processes on a miniaturised scale. -> Section three shows how to get information about the composition of a fluid using impedance spectroscopy (IS). IS is a relative new measurement method which analyses the complex impedance over a defined frequency range. Certain quantifiable electrical characteristics can be calculated out of this data. IS can be used very flexibly. Some possible uses are for example: the measurement of corrosion [12], cell detection in biochemical systems [11] or the capacity fade of lithium-ion batteries [13].
Original languageGerman (Austria)
Publication statusPublished - Nov 2010

Fields of science

  • 203017 Micromechanics
  • 202019 High frequency engineering
  • 202028 Microelectronics
  • 202039 Theoretical electrical engineering
  • 202037 Signal processing
  • 202027 Mechatronics
  • 202036 Sensor systems

JKU Focus areas

  • Mechatronics and Information Processing

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