Design and Fabrication of Microfluidic Devices for Electrokinetic Studies

Download or read book Design and Fabrication of Microfluidic Devices for Electrokinetic Studies written by Hyun Chul Jung and published by . This book was released on 2008 with total page 81 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: The objective of this thesis is to design and fabricate microfluidic devices for study of the fluid transport at the microscale and development of devices for biomedical applications, such as transport and manipulation of nanoparticles and biomolecules. For device fabrication, several materials including silicon, Pyrex glass, and polymer were explored. Inductively-coupled plasma reactive ion etching (ICP-RIE) was employed for fabrication of microfluidic channels on silicon and Pyrex glass and photolithography of SU-8 polymer was used to pattern microfluidic channels. The etching of Pyrex glass was carried out using SF6/Ar plasma. The etch rate and surface and sidewall smoothness were investigated systematically for dependence on bias voltage, ICP power, pressure, flow rate, and cathode temperature. Near vertical sidewalls and smooth etched surfaces were obtained by optimized etching parameters. The maximum etch rate, 0.65 um/min, was achieved at a pressure of 5 mTorr, a bias of 720 V, and an ICP power of 2500 W. For device packaging four types of bonding techniques (Fusion bonding, Anodic bonding, PDMS bonding, and SU-8 bonding) were investigated and optimized. . Microfluidic devices with five crosses for creating extensive and rotational flow patterns were designed and fabricated on silicon etched by ICP-RIE. The devices were bonded with Pyrex glass by anodic wafer bonding and packaged on a carrier using wire bonding before characterization. Under a DC bias, extensional flow of polystyrene beads has been demonstrated in a 20 um wide and 10 um deep 5 cross microfluidic device. Using the COMSOL software, Incompressible Navier Stokes equations and Conductive media DC modes were employed to simulate the electrokinetic flows by applying specific DC biasing boundary conditions. . The simulated results have a good agreement with the extensional flow observed on the fabricated devices.