IBM Research GmbH, Säumerstrasse 4, 8803 Rüschlikon, Switzerland.
Biomed Microdevices. 2011 Dec;13(6):1027-32. doi: 10.1007/s10544-011-9572-0.
Commercially available polydimethylsiloxane (PDMS) elastomers, such as Sylgard 184® are widely used in soft lithography and for microfluidic applications. These PDMS elastomers contain fillers to enhance their mechanical stability. The reinforcing fillers, often sub-micrometer small SiO(2) particles, tend to aggregate, swell with water, and thereby become cognoscible in a way that can strongly interfere with the visualization of micro-scale events taking place next to PDMS structures. As PDMS microfluidics are often used for studying cells and micro-/nanoparticles and for creating/handling nanodroplets, it has become highly desirable to employ a PDMS having high optical quality and that allows microscopy observation without artifacts. Here, we present a PDMS formulation that is free of fillers and has sufficiently low viscosity to perform a filtration step of the mixed prepolymers before curing. By molding a bi-layer microfluidic network (MFN), composed of a thin filler-free PDMS layer and a thicker Sylgard 184® backing layer, PDMS MFNs featuring both high optical quality and mechanical stability, can be fabricated.
市售的聚二甲基硅氧烷（PDMS）弹性体，如 Sylgard 184 ® ，广泛应用于软光刻和微流控应用。这些 PDMS 弹性体含有填充物以增强其机械稳定性。增强填料，通常是亚微米级的 SiO ₂ 颗粒，往往会聚集、吸水膨胀，从而变得可见，这可能会强烈干扰 PDMS 结构附近发生的微尺度事件的可视化。由于 PDMS 微流控技术常用于研究细胞和微/纳米颗粒以及创建/处理纳米液滴，因此非常希望使用具有高光学质量且没有伪影的 PDMS。在这里，我们提出了一种不含填料且粘度足够低的 PDMS 配方，可以在固化前对混合预聚物进行过滤。通过模制由薄的无填料 PDMS 层和较厚的 Sylgard 184 ® 背衬层组成的双层微流控网络（MFN），可以制造出具有高光学质量和机械稳定性的 PDMS MFN。
