Concentration polarization on surface patterned membranes

Surface pattern is a promising approach to enhance membrane performance while contradictory results have been reported on its impact on concentration polarization. Here, we provide an experimental and modeling study of the concentration polarization on patterned membranes by varying pattern size, solute size, surface hydrophilicity, and membrane orientation. Interesting trends were observed when comparing different membrane orientations, where relative concentration polarization degree (CPD) was found depend on molecular weight. Salts and small organic molecules encountered more severe CPD in the transverse mode, while molecules larger than a threshold value showed a different trend. Such threshold molecular weight increased at larger pattern size. Simulation results were consistent with experimental observations, and revealed the critical role of diffusivity on such phenomena. Results also showed more severe concentration polarization on patterned membranes in both parallel and transverse modes in most cases, compared to smooth membrane.

Automated summary

This study investigates the impact of surface pattern on concentration polarization in membranes. The results show interesting trends in concentration polarization degree depending on membrane orientation and solute size. The simulation results confirm the experimental observations and highlight the crucial role of diffusivity in this phenomenon. Compared to smooth membranes, patterned membranes generally exhibit more severe concentration polarization.