title: Reorganization of hydrogen bond network makes strong polyelectrolyte brushes pH-responsive.
abstract: Weak polyelectrolytes have found extensive practical applications owing to their rich pH-responsive properties. In contrast, strong polyelectrolytes have long been regarded as pH-insensitive based on the well-established fact that the average degree of charging of strong polyelectrolyte chains is independent of pH. The possible applications of strong polyelectrolytes in smart materials have, thus, been severely limited. However, we demonstrate that almost all important properties of strong polyelectrolyte brushes (SPBs), such as chain conformation, hydration, stiffness, surface wettability, lubricity, adhesion, and protein adsorption are sensitive to pH. The pH response originates from the reorganization of the interchain hydrogen bond network between the grafted chains, triggered by the pH-mediated adsorption-desorption equilibrium of hydronium or hydroxide with the brushes. The reorganization process is firmly identified by advanced sum-frequency generation vibrational spectroscopy. Our findings not only provide a new understanding of the fundamental properties of SPBs but also uncover an extensive family of building blocks for constructing pH-responsive materials.
authors.affiliation: Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, P. R. China.; Faculty of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, P. R. China.
authors.forename: Bo
authors.initials: B
authors.lastname: Wu
authors.affiliation: Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, P. R. China.
authors.forename: Xiaowen
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, P. R. China.
authors.forename: Jun
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, P. R. China.
authors.forename: Zan
authors.initials: Z
authors.lastname: Hua
authors.affiliation: Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, P. R. China.
authors.forename: Kangzhen
authors.identifier: 0000-0001-7787-9517
authors.initials: K
authors.lastname: Tian
authors.affiliation: Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, P. R. China.
authors.forename: Ran
authors.initials: R
authors.lastname: Kou
authors.affiliation: Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, P. R. China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, P. R. China.
authors.forename: Shuji
authors.initials: S
authors.lastname: Ye
authors.affiliation: Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, P. R. China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Luo
authors.affiliation: Department of Applied Mathematics, Research School of Physics and Engineering, Australian National University, Canberra, Australian Capital Territory 0200, Australia.
authors.forename: Vincent S J
authors.identifier: 0000-0002-8048-8397
authors.initials: VS
authors.lastname: Craig
authors.affiliation: Faculty of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, P. R. China.
authors.forename: Guangzhao
authors.identifier: 0000-0002-0219-3729
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, P. R. China.
authors.forename: Guangming
authors.initials: G
authors.lastname: Liu
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000327:Adsorption; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D008968:Molecular Conformation; D000071228:Polyelectrolytes / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry; D058525:Quartz Crystal Microbalance Techniques; D013499:Surface Properties
chemical_list: D000180:Acrylic Resins; D000071228:Polyelectrolytes; D011108:Polymers; D011506:Proteins
keywords: Polyelectrolyte brushes; hydrogen bond; quartz crystal microbalance; smart materials; sum-frequency generation vibrational spectroscopy; surface