TY - JOUR
T1 - Ion-Specific Hydration States of Zwitterionic Poly(sulfobetaine methacrylate) Brushes in Aqueous Solutions
AU - Sakamaki, Tatsunori
AU - Inutsuka, Yoshihiro
AU - Igata, Kosuke
AU - Higaki, Keiko
AU - Yamada, Norifumi L.
AU - Higaki, Yuji
AU - Takahara, Atsushi
N1 - Funding Information:
This work was supported by JSPS KAKENHI grant number JP18K05218. 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. This work was funded by the ImPACT Program of the 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” and was supported in part by the “Dynamic Alliance for Open Innovation Bridging Human, Environment and Materials” (MEXT) and “Integrated Research Consortium on Chemical Sciences” (MEXT). NR measurements were performed on BL-16 in the Materials and Life Science Facility (MLF), J-PARC, Japan (program nos. 2014S08 and 2017L2501).
Publisher Copyright:
© 2018 American Chemical Society.
PY - 2019/2/5
Y1 - 2019/2/5
N2 - The ion-specific hydration states of zwitterionic poly(3-(N-2-methacryloyloxyethyl-N,N-dimethyl)ammonatopropanesulfonate) (PMAPS) brushes in various aqueous solutions were investigated by neutron reflectivity (NR) and atomic force microscopy (AFM). The asymmetric hydration state of the PMAPS brushes was verified from the NR scattering-length density profiles, while the variation in their swollen thickness was complementary as determined from AFM topographic images. PMAPS brushes got thicker in any salt solutions, while the extent of swelling and the dimensions of swollen chain structure were dependent on the ion species and salt concentration in the solutions. Anion specificity was clearly observed, whereas cations exhibited weaker modulation in ion-specific hydration states. The anion specificity could be ascribed to ion-specific interactions between the quaternary ammonium cation in sulfobetaine and the anions. The weak cation specificity was attributed to the intrinsically weak cohesive interactions between the weakly hydrated sulfonate anion in sulfobetaine and the strongly hydrated cations. The ion-specific hydration of PMAPS brushes was largely consistent with the ion-specific aggregation state of the PMAPS chains in aqueous solutions.
AB - The ion-specific hydration states of zwitterionic poly(3-(N-2-methacryloyloxyethyl-N,N-dimethyl)ammonatopropanesulfonate) (PMAPS) brushes in various aqueous solutions were investigated by neutron reflectivity (NR) and atomic force microscopy (AFM). The asymmetric hydration state of the PMAPS brushes was verified from the NR scattering-length density profiles, while the variation in their swollen thickness was complementary as determined from AFM topographic images. PMAPS brushes got thicker in any salt solutions, while the extent of swelling and the dimensions of swollen chain structure were dependent on the ion species and salt concentration in the solutions. Anion specificity was clearly observed, whereas cations exhibited weaker modulation in ion-specific hydration states. The anion specificity could be ascribed to ion-specific interactions between the quaternary ammonium cation in sulfobetaine and the anions. The weak cation specificity was attributed to the intrinsically weak cohesive interactions between the weakly hydrated sulfonate anion in sulfobetaine and the strongly hydrated cations. The ion-specific hydration of PMAPS brushes was largely consistent with the ion-specific aggregation state of the PMAPS chains in aqueous solutions.
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U2 - 10.1021/acs.langmuir.8b03104
DO - 10.1021/acs.langmuir.8b03104
M3 - Article
C2 - 30441903
AN - SCOPUS:85058079904
SN - 0743-7463
VL - 35
SP - 1583
EP - 1589
JO - Langmuir
JF - Langmuir
IS - 5
ER -