Electrohydrodynamic Patterning of Polyethersulfone Membranes.

Microstructuring the surface of membranes is recognized as one of the effective strategies to mitigate the fouling phenomenon. Over the years, significant efforts have been undertaken to develop new techniques for altering the membrane surface topography at the micro- and nanoscale. However, all the previously suggested approaches suffer from some serious drawbacks that impede their widespread implementations, including cost, time, and cumbersomeness. In this study, we show that the electrohydrodynamic (EHD) patterning process can be successfully adopted to form surface patterns on polyethersulfone (PES) microfiltration membranes. The linear stability analysis and nonlinear numerical simulation are performed to theoretically predict the size of the created raised columnar structure (often called pillars). In contrast to the conventional EHD patterning process, the developed method works at room temperature and nonsolvent-induced phase separation is used to solidify the formed structures. An array of pillars was formed on the membrane surface, whose height and width were found to be as low as 31 ± 5 and 98 ± 12 μm, respectively. It is demonstrated that fabricating surface-patterned PES membranes does not require sophisticated facilities and precise control of process condition using this simple moldless method.