The present work deals with the microfluidic evolution of capillary surfaces that are formed during the priming of microcavity structures with a non-wetting liquid. Due to the large contact angle of the priming liquid, a trapping of air within the microcavities poses a major impediment to a complete filling. We tackle this issue by developing a two-dimensional analytical model describing the geometrical shape of capillary surfaces formed in microcavity structures. In particular, the model is employed to derive two quantitative conditions for a void-free priming of a microcavity structure in terms of its aspect ratio, rounding parameters and the channel width. Microfluidic experiments are performed to verify the analytical results. Finally, we make use of the model to demonstrate a pressure-driven aliquoting of a non-wetting sample liquid in a flow chamber with an array of 55 microcavities by introducing a second immiscible liquid acting as a sealant. In this way, our work constitutes a basis for the design of microcavity-based liquid aliquoting structures that are used in various fields of application like PCR arrays, cell culture chips or digital reaction arrays.

本工作涉及在用非润湿液体灌注微腔结构的过程中形成的毛细管表面的微流体演化。由于灌注液体的大接触角，空气在微腔内的捕获对完全填充构成了主要障碍。我们通过开发一个二维分析模型来解决这个问题，该模型描述了微腔结构中形成的毛细管表面的几何形状。特别地，该模型用于从其长宽比，舍入参数和通道宽度方面推导微腔结构的无孔灌注的两个定量条件。进行微流体实验以验证分析结果。最后，我们利用该模型通过引入第二种不混溶的液体作为密封剂，来演示压力驱动的非润湿样品液体在带有55个微腔阵列的流动室内的等分情况。这样，我们的工作构成了设计基于微腔的液体等分结构的基础，这些结构可用于各种应用领域，例如PCR阵列，细胞培养芯片或数字反应阵列。