Enhanced hydrophobicity of polyurethane via non-solvent induced surface aggregation of silica nanoparticles.
Fabrication of superhydrophobic surfaces from hydrophilic polymers has always been regarded as a challenge. In this study, to achieve superhydrophobic polyurethane (PU) surfaces, silica nanoparticles and ethanol as non-solvent were simultaneously utilized during a solution casting-based process. Such modified version of phase separation process was found to be highly efficient, and also it required much lower concentration of nanoparticles to achieve superhydrophobicity as compared to the previously reported methods in the literature. According to the proposed mechanism, non-solvent induces a more profound aggregation of silica nanoparticles at the surface's top layer causing the surface energy to be highly diminished, and thus, the water repellency is improved. Morphology and topography results showed that a unique "triple-sized" structure was formed on the surface of superhydrophobic samples. X-ray photoelectron spectroscopy results proved that both PU macromolecules and silica nanoparticles were concurrently present at the surface layer of the superhydrophobic sample. It was concluded that surface composition and roughness could be regarded as competing factors in achieving superhydrophobicity. Based on the obtained results, the proposed method exhibits a promising potential in large-scale fabrication of surface layers with superhydrophobic property. Moreover, a mechanism was also presented to further explicate the physics behind the suggested method.
School of Chemical Engineering, University of Tehran, P.O. Box 11155-4563, Tehran, Iran. Electronic address: Jseyfi@gmail.com.
Javad
J
Seyfi
Department of Polymer Engineering & Color Technology, Amirkabir University of Technology, Tehran, Iran.
Iman
I
Hejazi
School of Chemical Engineering, University of Tehran, P.O. Box 11155-4563, Tehran, Iran. Electronic address: Shjafari@ut.ac.ir.
Seyed Hassan
SH
Jafari
Department of Polymer Engineering, Faculty of Engineering, South Tehran Branch, Islamic Azad University, P.O. Box 19585-466, Tehran, Iran; Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Strasse 6, D-01069 Dresden, Germany.
Hossein Ali
HA
Khonakdar
Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Strasse 6, D-01069 Dresden, Germany.
Frank
F
Simon
Phase separation; Polyurethane; Roughness; Silica; Superhydrophobic