Qian Xiang, Zhang Wenhui, Peng Cheng, Liu Xingyang, Yu Quan, Ni Kai, Wang Xiaohao
Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China.
Department of Biology, South University of Science and Technology of China, Shenzhen 518055, China.
Micromachines (Basel). 2016 May 16;7(5):92. doi: 10.3390/mi7050092.
Polydimethylsiloxane (PDMS) membranes have been widely used in the microfluidic community to achieve various functions such as control, sensing, filter, In this paper, an experimental process was proposed to directly characterize the deformation of the on-chip PDMS membrane at large deformation based on the image processing method. High precision pressures were applied on the surface of the PDMS membrane with fixed edges and a series deformation of the PDMS membrane were captured by the imaging system. The Chan and Vese (CV) level set method was applied to segment the images of the deformed membrane. The volumes wrapped by the deformed membranes were obtained, and pressure-volumes relationships of the PDMS membranes with different geometry parameters were also calculated. Then the membrane capacitance can be derived by differentiating the curve of pressure-volumes. In addition, the theoretical estimation of the capacitance of the PDMS membrane at large deformation was also obtained through finite element simulation (FEM), which was in good agreement with the experimental results. These results are expected to be significant for designing and on-chip measuring of such PDMS membrane based microfluidic components in our future work.
聚二甲基硅氧烷（PDMS）膜已在微流体领域中广泛应用，以实现诸如控制、传感、过滤等各种功能。本文提出了一种基于图像处理方法直接表征片上PDMS膜在大变形情况下变形的实验过程。对具有固定边缘的PDMS膜表面施加高精度压力，并通过成像系统捕获PDMS膜的一系列变形。采用Chan和Vese（CV）水平集方法对变形膜的图像进行分割。获得变形膜所包裹的体积，并计算了具有不同几何参数的PDMS膜的压力-体积关系。然后通过对压力-体积曲线求导得出膜电容。此外，还通过有限元模拟（FEM）获得了PDMS膜在大变形情况下电容的理论估计值，其与实验结果吻合良好。预计这些结果对于我们未来工作中基于此类PDMS膜的微流体组件的设计和片上测量具有重要意义。
