title: Inertial separation in a contraction-expansion array microchannel.
abstract: We report a contraction-expansion array (CEA) microchannel that allows inertial size separation by a force balance between inertial lift and Dean drag forces in fluid regimes in which inertial fluid effects become significant. An abrupt change of the cross-sectional area of the channel curves fluid streams and produces a similar effect compared to Dean flows in a curved microchannel of constant cross-section, thereby inducing Dean drag forces acting on particles. In addition, the particles are influenced by inertial lift forces throughout the contraction regions. These two forces act in opposite directions each other throughout the CEA microchannel, and their force balancing determines whether the particles cross the channel, following Dean flows. Here we describe the physics and design of the CEA microfluidic device, and demonstrate complete separation of microparticles (polystyrene beads of 4 and 10 μm in diameter) and efficient exchange of the carrier medium while retaining 10 μm beads.
authors.affiliation: Department of Bio and Brain Engineering, College of Life Science and Bioengineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Myung Gwon
authors.initials: MG
authors.lastname: Lee
authors.forename: Sungyoung
authors.initials: S
authors.lastname: Choi
authors.forename: Je-Kyun
authors.initials: JK
authors.lastname: Park
mesh_terms: D055598:Chemical Phenomena; D003198:Computer Simulation; D004867:Equipment Design; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods*; D008856:Microscopy, Fluorescence; D008863:Microspheres; D010316:Particle Size; D011137:Polystyrenes / Q000737:chemistry
chemical_list: D011137:Polystyrenes