Department of Chemical and Biological Engineering, ECCH 111, UCB 424, University of Colorado, Boulder, CO 80309-0424, USA.
Lab Chip. 2011 Aug 21;11(16):2772-8. doi: 10.1039/c1lc20189a. Epub 2011 Jun 21.
In this work, a novel thiol-ene based photopolymerizable resin formulation was shown to exhibit highly desirable characteristics, such as low cure time and the ability to overcome oxygen inhibition, for the photolithographic fabrication of microfluidic devices. The feature fidelity, as well as various aspects of the feature shape and quality, were assessed as functions of various resin attributes, particularly the exposure conditions, initiator concentration and inhibitor to initiator ratio. An optical technique was utilized to evaluate the feature fidelity as well as the feature shape and quality. These results were used to optimize the thiol-ene resin formulation to produce high fidelity, high aspect ratio features without significant reductions in feature quality. For structures with aspect ratios below 2, little difference (<3%) in feature quality was observed between thiol-ene and acrylate based formulations. However, at higher aspect ratios, the thiol-ene resin exhibited significantly improved feature quality. At an aspect ratio of 8, raised feature quality for the thiol-ene resin was dramatically better than that achieved by using the acrylate resin. The use of the thiol-ene based resin enabled fabrication of a pinched-flow microfluidic device that has complex channel geometry, small (50 μm) channel dimensions, and high aspect ratio (14) features.
在这项工作中，展示了一种新型的基于硫醇-烯的光聚合树脂配方，该配方具有低固化时间和克服氧抑制的能力，可用于微流控器件的光光刻制造。特征保真度以及特征形状和质量的各个方面都被评估为各种树脂属性的函数，特别是曝光条件、引发剂浓度和抑制剂与引发剂的比例。利用光学技术来评估特征保真度以及特征形状和质量。这些结果用于优化硫醇-烯树脂配方，以生产具有高保真度和高纵横比的特征，而不会显著降低特征质量。对于纵横比低于 2 的结构，硫醇-烯和丙烯酸盐基配方之间的特征质量差异很小（<3%）。然而，在更高的纵横比下，硫醇-烯树脂表现出明显改善的特征质量。在纵横比为 8 时，硫醇-烯树脂的凸起特征质量明显优于使用丙烯酸盐树脂所获得的质量。使用基于硫醇-烯的树脂能够制造具有复杂通道几何形状、小（50μm）通道尺寸和高纵横比（14）特征的微流控器件。
