Formation of a Polymer Surface with a Gradient of Pore Size Using a Microfluidic Chip

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• 作者：Kristina Kreppenhofer ; Junsheng Li ; Rodrigo Segura ; Ludmilla Popp ; Massimiliano Rossi ; Pavleta Tzvetkova ; Burkhard Luy ; Christian J. K盲hler ; Andreas E. Guber ; Pavel A. Levkin
• 刊名：Langmuir
• 出版年：2013
• 出版时间：March 19, 2013
• 年：2013
• 卷：29
• 期：11
• 页码：3797-3804
• 全文大小：400K
• 年卷期：v.29,no.11(March 19, 2013)
• ISSN：1520-5827

文摘

Here we demonstrate the generation of polymer monolithic surfaces possessing a gradient of pore and polymer globule sizes from 0.1 to 0.5 渭m defined by the composition of two polymerization mixtures injected into a microfluidic chip. To generate the gradient, we used a PDMS microfluidic chip with a cascade micromixer with a subsequent reaction chamber for the formation of a continuous gradient film. The micromixer has zigzag channels of 400 脳 680 渭m² cross section and six cascades. The chip was used with a reversible bonding connection, realized by curing agent coating. After polymerization in the microfluidic chip the reversible bond was opened, resulting in a 450 渭m thick polymer film possessing the pore size gradient. The gradient formation in the microfluidic reaction chamber was studied using microscopic laser-induced fluorescence (渭LIF) and different model fluids. Formation of linear gradients was shown using the fluids of the same density by both diffusive mixing at flow rates of 0.001 mL/min and in a convective mixing regime at flow rates of 20 mL/min. By using different density fluids, formation of a two-dimensional wedge-like gradient controlled by the density difference and orientation of the microfluidic chip was observed.