Method of calculating porosity based on M44 element images of the Mueller matrix

As a drug carrier, the porosity of porous electrospun fiber can greatly affect its drug loading ability and stability. In this work, a method to calculate the porosity of porous electrospun fiber with a polarization micrograph is described. Different porosities of porous electrospun fibers were measured by scanning electron microscope images and transmission Mueller matrix M44 element images, respectively. Mueller matrix M44 element images were obtained after polarization micrograph and normalization. The pore areas of M44 images were extracted by region growing, and the contour parts were obtained by performing morphological operation on pore areas. The porosity calculated by the polarization microscope image is in good consistency with that measured by the scanning electron microscope. Our results will promote practical application of electrospun porous fibers in the early stage of screening a large number of porous materials in the biomedicine field.