Electrohydrodynamic Patterning of Polyethersulfone Membranes

Abstract

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.

Loading a High-Viscous Droplet via the Cone-Shaped Liquid Bridge Induced by an Electrostatic Force

“…The invariance of θ can be explained by the counterbalance of f e and f st at the air–liquid interface, where the increase of f e can be described by ,, Since the liquid cone develops from the hump, the radius of the liquid cone r c is related to the radius of the hump r 0 , and thus, f st can be represented by Combining eqs and , E is eliminated and thus θ depends only on ε r , implying the effect of U p on θ is negligible. While θ is constant, d tip is increased due to a large E ∼ U p / d g ,, and f e caused by the increase of U p . It promotes the acceleration of the flow and the decrease of t r .…”

“…Combining eqs 5 and 6, E is eliminated and thus θ depends only on ε r , implying the effect of U p on θ is negligible. While θ is constant, d tip is increased due to a large E ∼ U p /d g 21,46,47 and f e caused by the increase of U p . It promotes the acceleration of the flow and the decrease of t r .…”

“…The electrohydrodynamics (EHD) process has been applied in various fields, − such as EHD patterning and EHD jetting. EHD patterning focuses on the deformation of the liquid film induced by a large-size electrode.…”

Pattern formation in thin polymeric films via electrohydrodynamic patterning

“…In 2000, Schaffer et al reported a straightforward, cost-effective and contactless (positive replica) patterning technique, electrohydrodynamic patterning (EHDP), that creates and replicates lateral hierarchical structures with a submicrometre length scale on various kinds of materials ( e.g. thermoplastic polymer, 15–22 thermosetting polymer, 23–29 photocurable resin, 30–34 ceramic, 35–37 and so on) under an externally applied electric field. 38–47 Especially, the capability of EHDP with a featureless template to fast and economically create large-scale three-dimensional micro-scale structures, even though no long range order, is particularly attractive because the difficulty, time, and cost in designing and making pre-patterned templates limit the flexibility and wide application of conventional lithography, especially when large numbers of different patterns are to be fabricated.…”

Durability and Recoverability of Soft Lithographically Patterned Hydrogel Molds for the Formation of Phase Separation Membranes

“…Over the last decade, there have been many efforts to develop new techniques to fabricate membranes with micro and nano-sized features [23][24][25][26][27][28][29]. The current methods to fabricate patterned membranes can be classified as either mold-based patterning or direct printing approaches [23][24][25][26].…”