title: Patchy surfaces stabilize dextran-polyethylene glycol aqueous two-phase system liquid patterns.
abstract: This paper analyzes surface chemistry effects to stably pattern aqueous two-phase system (ATPS) droplets on chemically modified poly(dimethylsiloxane) (PDMS). Polyethylene glycol (PEG) and dextran (DEX) are used as phase-forming polymers for the ATPS. PDMS surface modifications studied include primary amine groups, carboxylic acid groups, and neutral polymer surfaces. The PDMS surfaces were characterized by fluorescent measurement, water and DEX contact angle measurements, and X-ray photoelectron spectroscopy (XPS) analysis to confirm surface properties. While homogeneous surfaces of different functional groups affect DEX droplet pinning somewhat, the most stable patterns were realized using surfaces with chemical heterogeneity. Arbitrary DEX solution patterning was achieved on a chemically patchy surface.
authors.affiliation: Department of Macromolecular Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States.
authors.forename: Taisuke
authors.initials: T
authors.lastname: Kojima
authors.forename: Shuichi
authors.initials: S
authors.lastname: Takayama
mesh_terms: D003911:Dextrans / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D003911:Dextrans; D014867:Water; D011092:Polyethylene Glycols