Facile approach for designing a novel micropatterned antiwetting membrane by utilizing 3D printed molds for improved desalination performance

Abstract

Membrane wetting in membrane distillation (MD) is a prominent issue during desalination operation, where the interfacial characteristics between the membrane surface and the feed stream are critical. In this study, an antiwetting membrane surface consisting of hierarchical microstructures was explored as a novel concept to understand the wetting behavior during the MD operation. A novel surface-engineered design of an antiwetting polyvinylidene fluoride (PVDF) membrane with micropatterned arrays obtained utilizing a 3D-printed molding phase separation method was thoroughly explored. In a novel introduction to this field, 3D-printed templates with micron-sized pillars in different shapes are used to generate air pockets when imprinted with a polymeric membrane. Additionally, hexadecyltrimethoxysilane was used as a chemical modifier for enhancing the hy-drophobic characteristics. Membrane properties were thoroughly analyzed through Fourier-transform infrared spectroscopy, atomic force microscopy, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy after successful fabrication of the surface and chemically engineered membrane. The chemically modified patterned membrane exhibited a higher contact angle of similar to 140 degrees and superior antiwetting behavior when compared to that of the plain PVDF membrane. Moreover, the engi-neered membrane showed superior MD performance in terms of salt rejection and water flux. Therefore, this paper demonstrates a simplistic approach to design a micropatterned functional membrane exhibiting anti-wetting and self-cleaning behavior during MD operation.