Ion-specific oil repellency of polyelectrolyte multilayers in water: Molecular insights into the hydrophilicity of charged surfaces

Xiaokong Liu, Chuan Leng, Li Yu, Ke He, Lauren Joan Brown, Zhan Chen, Jinhan Cho, Dayang Wang

Research output: Contribution to journalArticle

42 Citations (Scopus)


Surface wetting on polyelectrolyte multilayers (PEMs), prepared by alternating deposition of polydiallyldimethylammonium chloride (PDDA) and poly(styrene sulfonate) (PSS), was investigated mainly in water-solid-oil systems. The surface-wetting behavior of as-prepared PEMs was well correlated to the molecular structures of the uncompensated ionic groups on the PEMs as revealed by sum frequency generation vibrational and X-ray photoelectron spectroscopies. The orientation change of the benzenesulfonate groups on the PSS-capped surfaces causes poor water wetting in oil or air and negligible oil wetting in water, while the orientation change of the quaternized pyrrolidine rings on the PDDA-capped surfaces hardly affects their wetting behavior. The underwater oil repellency of PSS-capped PEMs was successfully harnessed to manufacture highly efficient filters for oil-water separation at high flux.

Original languageEnglish
Pages (from-to)4851-4856
Number of pages6
JournalAngewandte Chemie - International Edition
Issue number16
Publication statusPublished - 2015 Apr 13



  • interfaces
  • oil-water separation
  • photoelectronspectroscopy
  • structure elucidation
  • surface chemistry

ASJC Scopus subject areas

  • Chemistry(all)
  • Catalysis

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