van der Linden H J, Jellema L C, Holwerda M, Verpoorte E
Groningen Research Institute of Pharmacy, Groningen University, Antonius Deusinglaan 1, 9713AV, Groningen, The Netherlands.
Anal Bioanal Chem. 2006 Aug;385(8):1376-83. doi: 10.1007/s00216-006-0526-y. Epub 2006 Jun 14.
In this paper we present our first results on the realization of stable water/octanol, two-phase flows inside poly(dimethylsiloxane) (PDMS) microchannels. Native PDMS microchannels were coated with high molecular weight polymers to change the surface properties of the microchannels and thus stabilize the laminar flow profile. The polymers poly(2-hydroxyethyl methacrylate), poly(vinyl pyrrolidone), poly(ethylene oxide), poly(ethylene glycol), and poly(vinyl alcohol) were assessed for their quality as stabilization coatings after deposition from flowing and stationary solutions. Additionally, the influence of coating the microchannels homogeneously with a single kind of polymer or heterogeneously with two different polymers was investigated. From the experimental observations, it can be concluded that homogeneous polymer coatings with poly(2-hydroxyethyl methacrylate) and poly(vinyl pyrrolidone) led to the effective stabilization of laminar water/octanol flows. Furthermore, heterogeneous coatings led to two-phase flows which had a better-defined and more stable interface over long distances (i.e., 40-mm-long microchannels). Finally, the partitioning of fuchsin dye in the coated microchannels was demonstrated, establishing the feasibility of the use of the polymer-coated PDMS microchannels for determination of logP values in laminar octanol/water flows.
在本文中，我们展示了关于在聚二甲基硅氧烷（PDMS）微通道内实现稳定的水/辛醇两相流的首批结果。天然PDMS微通道用高分子量聚合物进行了涂层处理，以改变微通道的表面性质，从而稳定层流轮廓。对聚甲基丙烯酸2-羟乙酯、聚乙烯吡咯烷酮、聚环氧乙烷、聚乙二醇和聚乙烯醇等聚合物在从流动溶液和静态溶液中沉积后作为稳定涂层的质量进行了评估。此外，还研究了用单一聚合物均匀涂覆微通道或用两种不同聚合物非均匀涂覆微通道的影响。从实验观察结果可以得出结论，聚甲基丙烯酸2-羟乙酯和聚乙烯吡咯烷酮的均匀聚合物涂层能有效稳定层流水/辛醇流。此外，非均匀涂层导致两相流在长距离（即40毫米长的微通道）内具有更清晰、更稳定的界面。最后，展示了品红染料在涂覆微通道中的分配情况，证明了使用聚合物涂覆的PDMS微通道在层流辛醇/水流中测定logP值的可行性。
