多孔检测试纸渗透率实验及单胞数值模型

Permeability Experiment and Unit Cell Numerical Model of Porous Membranes for Paper-based Diagnostics

本文对侧流试纸NC膜(硝酸纤维素膜)分别进行水平和竖直工况下的毛细流动实验,通过数据拟合得到渗透率。拍摄了NC膜的SEM图片,统计出其粒径和孔径的分布。基于该微观结构图像,提出一套全新的用来预测NC膜渗透率的颗粒立方单胞模型。基于颗粒立方单胞模型,推导了孔隙率、孔径和粒径三者间的理论关系,并得到基于称重法所测孔隙率的验证。最后,采用该模型对渗透率进行数值模拟,并与实验结果进行对比。结果表明,颗粒立方单胞模型能够较好地刻画NC膜的结构和渗流特性。

Rate-of-rise experiments were performed to measure the permeability of nitrocellulose(NC) membranes for lateral flow tests. In order to characterize the microstructure of NC membranes,the porosity was measured using the weighting method. SEM images were then taken to statistically determine particle and pore size distributions. A novel particle-cubic unit cell model was proposed to represent the pore geometry of NC membranes. Based on the model, the theoretical relation between porosity, pore size and particle size was derived, which agreed well with the experimental data. Fluid flow in the particle-cubic model was numerically simulated with periodic boundary conditions to calculate the permeability. Results obtained using the present numerical model agreed well with experimentally measured permeability.