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Publication Citation: Solution and Surface Composition Gradients via Microfluidic Confinement: Fabrication of a Statistical-Copolymer-Brush Composition Gradient

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Author(s): Chang Xu; Susan E. Barnes; Tao Wu; Daniel A. Fischer; Dean M. DeLongchamp; J Batteas; Kathryn L. Beers;
Title: Solution and Surface Composition Gradients via Microfluidic Confinement: Fabrication of a Statistical-Copolymer-Brush Composition Gradient
Published: June 06, 2006
Abstract: A simple method to generate solution gradients through microfluidic confinement is described. The solution gradient inside a microchannel was formed by varying the relative infusion rates of two solutions that differed in compositions. The establishment and maintenance of a stable solution gradient in a microchannel was confirmed using the Raman spectroscopy. The stable solution gradient was explored to synthesize a surface-grafted statistical copolymer brush gradient of n-butyl methacrylate (BMA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) via surface-initiated atom transfer radical polymerization (ATRP). The resulting gradient exhibits a surface energy change from the homopolymer brush of BMA to that of DMAEMA, as indicated by water contact angle measurement. Further evidence from near-edge absorption fine structure (NEXAFS) spectroscopy confirmed the gradual transition of surface composition from one end of the substrate to the other.
Citation: Advanced Materials
Volume: 18
Pages: pp. 1427 - 1430
Keywords: ATRP;copolymer brushes;gradient thin films;microfluid
Research Areas: Microfluidics, Polymers
PDF version: PDF Document Click here to retrieve PDF version of paper (205KB)