Controlling the surface wettability of poly(sulfone) films by UV-assisted treatment: benefits in relation to plasma treatment

Authors

  • Felipe Kessler,

    Corresponding author
    • Laboratório de Fotoquímica e Superfícies, Departamento de Físico-Química, Instituto de Química—UFRGS, Av. Bento Gonçalves 9500, CEP 91501970, Porto Alegre, RS, Brazil
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  • Sidiney Kühn,

    1. Laboratório de Fotoquímica e Superfícies, Departamento de Físico-Química, Instituto de Química—UFRGS, Av. Bento Gonçalves 9500, CEP 91501970, Porto Alegre, RS, Brazil
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  • Cláudio Radtke,

    1. Laboratório de Superfícies e Interfaces Sólidas, Departamento de Físico-Química, Instituto de Química—UFRGS, Av. Bento Gonçalves 9500, CEP 91501970, Porto Alegre, RS, Brazil
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  • Daniel E. Weibel

    1. Laboratório de Fotoquímica e Superfícies, Departamento de Físico-Química, Instituto de Química—UFRGS, Av. Bento Gonçalves 9500, CEP 91501970, Porto Alegre, RS, Brazil
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Correspondence to: Felipe Kessler, Laboratório de Fotoquímica e Superfícies, Departamento de Físico-Química, Instituto de Química—UFRGS, Av. Bento Gonçalves 9500, CEP 91501970, Porto Alegre, RS, Brazil. E-mail: felipekessler@gmail.com

Abstract

Hydrophilic and superhydrophilic surfaces of poly(sulfone) (PSU) thin films were prepared by UV irradiation in the presence of O2 or acrylic acid (AA) vapor. Treated surfaces were then investigated by water contact angle measurements, Fourier transformed IR spectroscopy in attenuated total reflectance mode (FTIR-ATR), X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure (NEXAFS) and AFM. Water contact angle values of treated PSU films using either O2 or AA vapor as the reactive atmosphere reached about 6° after more than 120 min of irradiation. FTIR-ATR, XPS and NEXAFS analysis showed incorporation of oxygenated groups onto the surface that led to its hydrophilic characteristics. In addition, when AA vapor was used as the reactive atmosphere, a photopolymerization process of poly(acrylic acid) onto the surface of the PSU was observed. AFM analysis showed a very low level of roughness after the treatments. A comparison of UV-assisted surface modifications of PSU films with traditional plasma treatments showed excellent qualitative agreement between the two techniques. Our results show that UV-assisted treatments in the presence of AA vapor or O2 are efficient ways of controlling the surface wettability and functionalities grafted on the surface of PSU films. This treatment can be considered as a permanent dry grafting method that resists aging and uses a simple experimental setup. © 2012 Society of Chemical Industry

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