Micelle-like macrovoids in mixed matrix PVDF-PTFE hollow fiber membranes

May May Teoh, Tai Shung Chung*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Unique 'micelle-like' macrovoids have been observed for the first time in the polyvinylidene fluoride-polytetrafluoroethylene (PVDF-PTFE) hollow fiber membranes. FESEM results show that the incorporation of 30 and 40 wt% PTFE particles (<1 μm) reduces the number of finger-like macrovoids in the membrane matrix, while micelle-like marcovoids (about 10 μm in size) are formed when PTFE loading is increased to 50 wt% or higher. 50 wt% PTFE is the critical particle concentration for micelle-like macrovoid formation. The origins of micelle formation may be attributed to the adhesion and cohesion forces between air bubbles and particles in the supersaturated PTFE solution. A more rigorous degassing of the PVDF-T50 polymer dope solution may enhance the suspension homogeneity and eliminate the micelle-like macrovoid formation. It is therefore concluded that the micelle-like macrovoid formation arises from the agglomeration of gas bubbles upon PTFE particles with the aid of water diffusion and convection during the phase inversion of membrane formation.

Original languageEnglish (US)
Pages (from-to)5-10
Number of pages6
JournalJournal of Membrane Science
Issue number1-2
StatePublished - Aug 10 2009
Externally publishedYes


  • Hollow fibers
  • Micelle-like macrovoids
  • Mixed matrix membranes

ASJC Scopus subject areas

  • Biochemistry
  • General Materials Science
  • Physical and Theoretical Chemistry
  • Filtration and Separation


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