title: Surface hydrophobicity of fluorinated block copolymers enhanced by supercritical carbon dioxide annealing.
abstract: Supercritical carbon dioxide (scCO2) annealing enhances the hydrophobicity of the surfaces of asymmetric perfluorinated block copolymers. X-ray photoelectron spectroscopy (XPS) and contact angle measurement reveal that the surface domains of the fluorinated block (PF) of poly[styrene-block-4-(perfluorooctylpropyloxy)styrene] (PS-PF) become thicker than those annealed in a vacuum. Consequently, the contact angles of water on the surfaces of PS-PF block copolymers significantly increase after the scCO2 annealing compared to those annealed in a vacuum. The surface hydrophobicity enhanced by the scCO2 annealing is related to the thickness of the surface PF domain and the conformation of the PF block.
authors.affiliation: Nanotechnology Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 5, 1-1-1, Higashi, Tsukuba, Ibaraki 305-8565, Japan. yokoyama@ni.aist.go.jp
authors.forename: Hideaki
authors.initials: H
authors.lastname: Yokoyama
authors.forename: Kenji
authors.initials: K
authors.lastname: Sugiyama