Measurement of transient transport process of different molecules across mixed fiber (CA-CN) membrane by pixelated-array masked phase-shifting interferometer

The quantitative analysis of cross-membrane and diffusion transportation process of different molecules is of critical importance for the understanding of molecular mechanism of bio-process as well as industrial membrane engineering. Precise measurement and visualization of such molecular mass transfer process in cross-membrane system are the key issues in such analysis. In this study, the visualizing characterization was conducted to experimentally analyze the cross mixed fiber (CA-CN) membrane process by a newly proposed Pixelated-Array Masked Phase-Shifting Interferometer system. The mixed fiber (CA-CN) membrane is with four different average micro-hole diameter of 1.2 μm, 0.8 μm, 0.45 μm and 0.2 μm. Both the cross-membrane and after-membrane diffusion process were examined by analytical model and then realized by interferometer measurement by comparing the fringes generalized by this non-contact visualization method. It was found that the localized feature will dominant the cross-membrane transportation process and the ensuing diffusion process will largely be dependent on the localized transportation: for the case of sodium chloride, local equilibrium happen very quickly but the vertical convection also show different speed in the horizontal direction, while for glycerin, and BSA (bovine serum albumin) solution system, the cross-membrane and diffusion process show much different behaviors, which indicates possible control process for membrane transportation.