Gas and Vapor Transport in Mixed Matrix Membranes Based on Amorphous Teflon AF1600 and AF2400 and Fumed Silica

Maria-Chiara Ferrari, M. Galizia, M. G. De Angelis, G. C. Sarti

Research output: Contribution to journalArticlepeer-review


The enhancement of gas and vapor transport rates induced by the addition of fumed silica nanoparticles to fluorinated glassy polymers is interpreted and quantitatively modeled considering the additional free volume created by incorporation of filler. That effect can be evaluated accurately from gas solubility data, using the NELF model. The solubility of CH4 and CO2 in matrices of Teflon AF1600 and AF2400, filled with variable amounts of fumed silica nanoparticles, was measured at 35 °C; the solubility of n-C4 and n-C5 vapors, as well as their diffusivity and the dilation induced in the same polymer matrices, was also measured at 25 °C. The fractional free volume (FFV) values, estimated on the basis of CH4 solubility data, were used to predict the solubility of the other penetrants inspected, with excellent agreement with experimental data. In addition, a single empirical correlation can be drawn, for both AF1600 and AF2400-based mixed matrices, between the infinite dilution diffusivity of vapors and the FFV value calculated from solubility data. Similarly, a simple correlation valid for both matrices is obtained as well for the dependence of diffusivity on penetrant concentration. Finally, use of the NELF model also allows an estimate of the swelling induced by the sorption process on the basis of virtually one simple data point of gas solubility.
Original languageEnglish
Pages (from-to)11920-11935
Number of pages16
JournalIndustrial & Engineering Chemistry Research
Issue number23
Publication statusPublished - 9 Apr 2010


  • Data points
  • Diffusivities
  • Empirical correlations
  • Experimental data
  • Fractional free volume
  • Fumed silica nanoparticles
  • Fumed silicas
  • Gas solubility
  • Glassy polymers
  • Infinite-dilution diffusivity
  • Mixed matrix membranes
  • Polymer matrices
  • Solubility data
  • Sorption process
  • Vapor transport
  • Diffusion
  • Filled polymers
  • Nanoparticles
  • Polymers
  • Polytetrafluoroethylenes
  • Silica
  • Solubility
  • Sorption
  • Vapors
  • Matrix algebra


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