Original Article

Hydration structure of reverse osmosis membranes studied via neutron scattering and atomistic molecular simulation

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Reverse osmosis (RO) membranes are becoming popular as energy saving and environmentally friendly materials for the desalination of water. Toward the rational design of RO membranes, we performed contrast-variation neutron scattering measurements and atomistic molecular dynamics (MD) simulations on polyamide/water systems with various water contents and deuteration ratios. The experimental and computational structure factors showed good agreement for all the systems examined. The structure of the water-rich polyamide/water system obtained from MD calculation showed that the water clusters are well connected to each other, and a relatively large number of water molecules are present at a distance over 3 Å from the polyamide. The partial radial distribution functions were calculated, and strong interactions were observed between water and the carboxyl group in polyamide. Thus, the water permeability of the RO membrane can be expected to improve when more carboxyl groups are introduced. In addition, the polyamide–polyamide interaction was found to be equal to or smaller than the polyamide–water interactions and relatively weak in the water-rich system.

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  1. 1.

    Frost & Sullivan. CEO 360 degree perspective on the global membrane-based water and wastewater treatment market. San Antanio, USA; 2013.

  2. 2.

    New desalination capacity, 1980–2009 chart. Glob Water Intell. 2009;10:7.

  3. 3.

    National Research Council of the National Academies. Desalination: A national perspective. National Academies Press Washington, D.C., USA; 2008.

  4. 4.

    The big dipper. Contracted desalination capacity forecast-chart. Glob Water Intell. 2009;3:7.

  5. 5.

    Petersen RJ. Composite reverse osmosis and nanofiltration membranes. J Memb Sci. 1993;83:81–150.

  6. 6.

    Lloyd DR (Ed.) Materials science of synthetic membranes. ACS Symposium Series, No. 269. (American Chemical Society, Washington D.C., USA, 1985).

  7. 7.

    Uemura T, Inoue T. Electron microscopic study of ultrathin solute barrier layer of composite membranes and their solute transport phenomena by the addition of alkali metal salts. In: Drioli E, Nakagaki M, editors. Membranes and membrane processes. Plenum Press New York, USA; 1984. p. 379-86 .

  8. 8.

    Pacheco FA, Pinnau I, Reinhard M, Leckie JO. Characterization of isolated polyamide thin films of RO and NF membranes using novel TEM techniques. J Memb Sci. 2010;358:51–59.

  9. 9.

    Uemura T, Kotera K, Henmi M, Tomioka H. Membrane technology in seawater desalination: History, recent developments and future prospects. Desalin Water Treat. 2011;33:283–8.

  10. 10.

    Henmi M, Fusaoka Y, Tomioka H, Kurihara M. High performance RO membranes for desalination and wastewater reclamation and their operation results. Water Sci Technol. 2010;62:2134–2140.

  11. 11.

    Kurihara M, Hanakawa M. Mega-ton water system: Japanese national research and development project on seawater desalination and wastewater reclamation. Desalination. 2013;308:131–7.

  12. 12.

    Lin L, Lopez R, Ramon GZ, Coronell O. Investigating the void structure of the polyamide active layers of thin-film composite membranes. J Memb Sci. 2016;497:365–76.

  13. 13.

    Freger V. Swelling and morphology of the skin layer of polyamide composite membranes: An atomic force microscopy study. Environ Sci Technol. 2004;38:3168–75.

  14. 14.

    Tomioka H, Henmi M, Nakatsuji K, Kurihara M. High boron removal seawater RO membrane. In: Proceedings of the 4th International Membrane Conference. Harrogate, UK; International Water Association; 2007.

  15. 15.

    Bird RB, Stewart WE, Lightfoot EN. Transport phenomena. Wiley, Hotoken, USA; 1960.

  16. 16.

    Perkins SJ. Structural studies of proteins by high-flux X-ray and neutron solution scattering. Biochem J. 1988;254:313–27.

  17. 17.

    Pedersen JS, Svaneborg C, Almdal K, Hamley IW, Young RN. A small-angle neutron and X-ray contrast variation scattering study of the structure of block copolymer micelles: Corona shape and excluded volume interactions. Macromolecules. 2003;36:416–33.

  18. 18.

    Neutron scattering lengths and cross sections. 2013. https://www.ncnr.nist.gov/resources/n-lengths/. Accessed 7 Sept 2017.

  19. 19.

    Henmi M, Tomioka H, Kawakami T. Performance advancement of high boron removal seawater RO membranes. Abstr B IDA World Congr Desalin Water Reuse. 2007;61.

  20. 20.

    Andersen HC. Molecular dynamics simulations at constant pressure and/or temperature. J Chem Phys. 1980;72:2384–93.

  21. 21.

    Tuckerman M, Berne BJ, Martyna GJ. Reversible multiple time scale molecular dynamics. J Chem Phys. 1992;97:1990–2001.

  22. 22.

    Materials studio is a graphical molecular modeling program that incorporates diverse popular molecular modeling codes in materials sciences, life sciences, and drug design. BIOVIA Materials Studio. http://accelrys.com/products/collaborative-science/biovia-materials-studio/. (Accessed 7 Sept 2017).

  23. 23.

    Ishikiriyama K, Todoki M. Evaluation of water in silica pores using differential scanning calorimetry. Thermochim Acta. 1995;256:213–26.

  24. 24.

    Yamada-Nosaka A, Ishikiriyama K, Todoki M, Tanzawa H. 1H-NMR studies on water in methacrylate hydrogels I. J Appl Polym Sci. 1990;39:2443–52.

  25. 25.

    Kishi A, Tanaka M, Mochizuki A. Comparative study on water structures in polyHEMA and polyMEA by XRD-DSC simultaneous measurement. J Appl Polym Sci. 2009;111:476–81.

  26. 26.

    Miwa Y, Ishida H, Tanaka M, Mochizuki A. 2H-NMR and 13C-NMR study of the hydration behavior of poly(2-methoxyethyl acrylate), poly(2-hydroxyethyl methacrylate), and poly(tetrahydrofurfuryl acrylate) in relation to their blood compatibility as biomaterials. J Biomater Sci Polym Ed. 2010;21:1911–24.

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The authors greatly acknowledge Prof. Osamu Yamamuro (The University of Tokyo), Prof. Kenji Maruyama (Niigata University) and Prof. Toru Ishigaki (Ibaraki University) for the technical advice about the data analysis of neutron scattering. The neutron experiments at the Materials and Life Science Experimental Facility of the J-PARC were performed under the user programs (Proposal No. 2014AM0006, 2014AM0007).

Author information


  1. Advanced Materials Research Laboratories, Toray Industries, Inc., 2-1 Sonoyama 3-chome, Otsu, Shiga, 520-0842, Japan

    • Tomonori Kawakami
  2. Material Science Laboratories 2nd Material Science Laboratory, Toray Research Center, Inc., 3-7 Sonoyama 3-chome, Otsu, Shiga, 520-0842, Japan

    • Masaru Nakada
    •  & Kazuyuki Okada
  3. Global Environment Research Laboratories, Toray Industries, Inc., 2-1 Sonoyama 3-chome, Otsu, Shiga, 520-0842, Japan

    • Harutoki Shimura
    •  & Masahiro Kimura


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Conflict of interest

The author declares that they have no competing interests.

Corresponding author

Correspondence to Harutoki Shimura.

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