TY - JOUR
T1 - Effect of Charged Group Spacer Length on Hydration State in Zwitterionic Poly(sulfobetaine) Brushes
AU - Higaki, Yuji
AU - Inutsuka, Yoshihiro
AU - Sakamaki, Tatsunori
AU - Terayama, Yuki
AU - Takenaka, Ai
AU - Higaki, Keiko
AU - Yamada, Norifumi L.
AU - Moriwaki, Taro
AU - Ikemoto, Yuka
AU - Takahara, Atsushi
N1 - Funding Information:
This work was supported by the Photon and Quantum Basic Research Coordinated Development Program of the Ministry of Education, Culture, Sports, Science and Technology, Japan. Part of this work was funded by ImPACT Program of Council for Science, Technology and Innovation (Cabinet Office, Government of Japan). This work was performed under the Cooperative Research Program of “Network Joint Research Center for Materials and Devices”. FT-IR measurements were performed at BL43IR (2013B1177, 2015B1313, 2016A1329, and 2016B1703) in SPring-8 with the approval of the Japan Synchrotron Radiation Research Institute (JASRI). NR measurements were performed on BL16 in Materials and Life Science Facility (MLF), J-PARC, Japan (program nos. 2009S08 and 2014S08). We gratefully acknowledge Y. Harada, K. Yamazoe, and Y. Cui (Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo) for kind support for humidity controlled IR measurements in BL43IR.
Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/8/29
Y1 - 2017/8/29
N2 - Effect of alkyl chain spacer length between the charged groups (CSL) in zwitterionic poly(sulfobetaine) (PSB) brushes on the hydration state was investigated. PSB brushes with ethyl (PMAES), propyl (PMAPS), or butyl (PMABS) CSL were prepared by surface-initiated atom transfer radical polymerization on silicon wafers. Hydration states of the PSB brushes in aqueous solutions and/or humid vapor were investigated by contact angle measurement, infrared spectroscopy, AFM observation, and neutron reflectivity. The PSB brushes are swollen in humid air and deionized water due to the hydration of the charged groups leading to the reduction of hydrated PSB brushes/water interfacial free energy. The hydrated PSB brushes exhibit clear interface with low interfacial roughness due to networking of the PSB brush chains through association of the SBs. The hydrated PSB brushes produce diffusive swollen layer in the presence of NaCl because of the charge screening followed by SB dissociation by the bound ions. The ionic strength sensitivity in the hydration got more significant with increasing the CSL in SBs because of the augmentation in partial charge by charged group separation.
AB - Effect of alkyl chain spacer length between the charged groups (CSL) in zwitterionic poly(sulfobetaine) (PSB) brushes on the hydration state was investigated. PSB brushes with ethyl (PMAES), propyl (PMAPS), or butyl (PMABS) CSL were prepared by surface-initiated atom transfer radical polymerization on silicon wafers. Hydration states of the PSB brushes in aqueous solutions and/or humid vapor were investigated by contact angle measurement, infrared spectroscopy, AFM observation, and neutron reflectivity. The PSB brushes are swollen in humid air and deionized water due to the hydration of the charged groups leading to the reduction of hydrated PSB brushes/water interfacial free energy. The hydrated PSB brushes exhibit clear interface with low interfacial roughness due to networking of the PSB brush chains through association of the SBs. The hydrated PSB brushes produce diffusive swollen layer in the presence of NaCl because of the charge screening followed by SB dissociation by the bound ions. The ionic strength sensitivity in the hydration got more significant with increasing the CSL in SBs because of the augmentation in partial charge by charged group separation.
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U2 - 10.1021/acs.langmuir.7b01935
DO - 10.1021/acs.langmuir.7b01935
M3 - Article
C2 - 28737401
AN - SCOPUS:85028563554
SN - 0743-7463
VL - 33
SP - 8404
EP - 8412
JO - Langmuir
JF - Langmuir
IS - 34
ER -