Absolute Orientations of Water Molecules at Zwitterionic Polymer Interfaces and Interfacial Dynamics after Salt Exposure

Xiaofeng Han, Chuan Leng, Qing Shao, Shaoyi Jiang, Zhan Chen

Research output: Contribution to journalArticlepeer-review

56 Scopus citations

Abstract

Nonfouling zwitterionic polymers have wide applications ranging from the naval industry to biomedical engineering. Strong hydration at polymer surfaces has been proven to be crucial to their nonfouling property, but the absolute orientations of water molecules on the polymers and the competition between water and salt binding have not been elucidated. In this work, the absolute orientations of water molecules on two zwitterionic polymer brushes, poly(carboxybetaine methacrylate) (pCBMA) and poly(sulfobetaine methacrylate) (pSBMA), were measured using regular and phase-sensitive sum frequency generation (SFG) vibrational spectroscopy. The pH-dependent studies in a pH range from 2 to 12 showed that at a pH of 7, the water absolute orientations are different on the pCBMS and pSBMA surfaces. Phase-sensitive SFG studies confirmed the results obtained from the pH-dependent measurements. Salt effects on the hydration of zwitterionic polymers were examined as a function of time, which indicated that the pCBMA surface and the associated interfacial water exhibit a slow restructuring process after salt binding (likely due to the strong binding of pCBMA with water), whereas the surface of pSBMA and the associated water have a fast change after salt binding.

Original languageEnglish
Pages (from-to)1327-1334
Number of pages8
JournalLangmuir
Volume35
Issue number5
DOIs
StatePublished - Feb 5 2019

Bibliographical note

Publisher Copyright:
© 2018 American Chemical Society.

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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