title: Multiple flow profiles for two-phase flow in single microfluidic channels through site-selective channel coating.
abstract: An approach to control two-phase flow systems in a poly(dimethylsiloxane) (PDMS) microfluidic device using spatially selective surface modification is demonstrated. Side-by-side flows of ethanol : water solutions containing different polymers are used to selectively modify both sides of a channel by laminar flow patterning. Introduction of air pockets during modification allows for control over the length of the channel section that is modified. This approach makes it possible to achieve slug flow and side-by-side flow of water : 1-octanol simultaneously within the same PDMS channel, without the need of additional structural elements. A key finding is that conditioning of the PDMS channels with 1-octanol before polymer deposition is crucial to achieving stable side-by-side flows.
authors.affiliation: Center for Systems Chemistry, Stratingh Institute for Chemistry, Faculty of Mathematics and Natural Sciences, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
authors.forename: Hella
authors.initials: H
authors.lastname: Logtenberg
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Lopez-Martinez
authors.forename: Ben L
authors.initials: BL
authors.lastname: Feringa
authors.forename: Wesley R
authors.initials: WR
authors.lastname: Browne
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Verpoorte
mesh_terms: D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D000431:Ethanol / Q000737:chemistry; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods; D015394:Molecular Structure; D012394:Rosaniline Dyes / Q000737:chemistry; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D004129:Dimethylpolysiloxanes; D012394:Rosaniline Dyes; D014867:Water; D000431:Ethanol; C013830:baysilon