title: Preparation of gradient polyacrylate brushes in microchannels.
abstract: Gradient poly(2-hydroxyethyl methacrylate) brushes were synthesized by surface-initiated atom transfer radical polymerization (ATRP) confined within a microfluidic system on a silicon wafer. For ATRP, surface initiator, 11-((2-bromo, 2-methyl) propionyloxy) undecyltrichlorosilane (BUC), was synthesized, and allowed to self-assemble in a monolayer on the Si wafer, as analyzed by XPS to confirm the presence of an ester group of BUC. A solution containing 2-hydroxyethylmethacrylate, Cu catalyst, and bipyridin was allowed to flow in a microchannel and polymerize, resulting in the brushes with a gradient of thickness on the Si wafer. Using ellipsometry and ATR-IR, we verified the gradients of well established brushes on the Si wafer. AFM and contact angle data showed that wettability of the brushes did not exhibit a linear relationship with hydrophilicity.
authors.affiliation: Department of Chemistry and Research Institute for Natural Sciences, Hanyang University, Seoul 133-791, Korea.
authors.forename: Seongyeol
authors.initials: S
authors.lastname: Lee
authors.forename: Sang Gil
authors.initials: SG
authors.lastname: Youm
authors.forename: Yeari
authors.initials: Y
authors.lastname: Song
authors.forename: Whikum
authors.initials: W
authors.lastname: Yi
authors.forename: Daewon
authors.initials: D
authors.lastname: Sohn