Post-fabrication modification of electrospun nanofiber mats with polymer coating for membrane distillation applications

Evyatar Shaulsky, Siamak Nejati, Chanhee Boo, Francois Perreault, Chinedum O. Osuji, Menachem Elimelech

Research output: Contribution to journalArticle

44 Scopus citations

Abstract

Post-treatment of electrospun nanofibers is a versatile and scalable approach for the fabrication of membranes with controlled pore size, porosity, and morphology. In this study, we demonstrate a novel solution-based approach for the fabrication of membrane distillation (MD) membranes with adjustable pore size and performance through non-solvent induced phase separation of a polymeric solution over an electrospun fiber mat. Poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) was dissolved in a blend of acetone and dimethylacetamide and used to produce a highly porous electrospun fiber mat with an average pore diameter of ~1.2 µm. Surface coating of the PVDF-HFP nanofibers with polyvinylidene fluoride (PVDF) through phase separation enabled control of the membrane pore size by filling the empty domains between the fibers. The coated fiber mats were characterized for their surface hydrophobicity, porosity, and structure. The PVDF polymeric coating layer integrated within the electrospun mat decreased the average pore diameter to <0.6 µm without compromising the surface hydrophobicity. By controlling the depth of the PVDF coating layer within the substrate, we were able to fabricate robust membranes with near complete salt rejection (>99.9%) and a water flux of 30 L m−2 h−1 in direct contact MD experiments with 40 °C temperature difference between the feed and permeate solutions. This coating procedure is compatible with current roll-to-roll membrane fabrication processes, making it a viable approach for large-scale fabrication of electrospun membranes with exceptional performance for MD applications.

Original languageEnglish (US)
Pages (from-to)158-165
Number of pages8
JournalJournal of Membrane Science
Volume530
DOIs
StatePublished - May 15 2017

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Keywords

  • Adjustable pore size
  • Asymmetric membrane
  • Electrospun fiber mats
  • Membrane distillation
  • Microporous membranes for MD

ASJC Scopus subject areas

  • Biochemistry
  • Materials Science(all)
  • Physical and Theoretical Chemistry
  • Filtration and Separation

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