title: Structure of water at zwitterionic copolymer film-liquid water interfaces as examined by the sum frequency generation method.
abstract: A copolymer film composed of zwitterionic carboxymethylbetaine (CMB) and n-butyl methacrylate (BMA), Poly(CMB-r-BMA), was cast on a flat plane of an octadecyltrichlorosilane (ODS)-modified fused quartz prism with a semi-cylindrical shape. CH stretching of the polymer film and O-H stretching of water at the surface of the film were examined using the sum frequency generation (SFG) technique. The C-H stretching band of the cast film, indicating a gauche defect of the film, was affected by the contact medium including dry nitrogen, water vapor-saturated nitrogen and liquid water. In contrast, the C-H stretching of an octadecyl group introduced onto the quartz prism for stable attachment of the cast film was not significantly changed by the contact medium. The O-H stretching band indicated that water molecules at the surface of the Poly(CMB-r-BMA) film in contact with liquid water were not greatly oriented in comparison with those at the surfaces of a bare prism, an ODS SAM-modified prism, and a prism covered with a PolyBMA film or a copolymer film of BMA and methacrylic acid or 2-(dimethylamino)ethyl methacrylate. A similar small perturbation of the structure of water was previously observed in the vicinity of water-soluble zwitterionic polymers and zwitterionic copolymer films using Raman and attenuated total reflection infrared spectroscopies, respectively. A distinct effect of charge neutralization to diminish the perturbation of the structure of interfacial water around polymer materials was suggested.
authors.affiliation: Department of Applied Chemistry, Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Kondo
authors.affiliation: Department of Applied Chemistry, Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan.
authors.forename: Kouji
authors.initials: K
authors.lastname: Nomura
authors.affiliation: Department of Applied Chemistry, Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Gemmei-Ide
authors.affiliation: Department of Applied Chemistry, Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan. Electronic address: kitano@eng.u-toyama.ac.jp.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kitano
authors.affiliation: National Institute for Materials Science (NIMS) and Global Research Center for Environment and Energy Based on Nanomaterials Science (GREEN), Tsukuba 305-0044, Japan.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Noguchi
authors.affiliation: National Institute for Materials Science (NIMS) and Global Research Center for Environment and Energy Based on Nanomaterials Science (GREEN), Tsukuba 305-0044, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Uosaki
authors.affiliation: R&D Laboratory, Osaka Organic Chemical Industry, Kashiwara 582-0020, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Saruwatari
mesh_terms: D008567:Membranes, Artificial; D011108:Polymers / Q000737:chemistry*; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D008567:Membranes, Artificial; D011108:Polymers; D014867:Water
keywords: Interfacial water; Orientation of water; Sum frequency generation; Zwitterionic copolymer film