Biomimetic Polyelectrolytes Based on Polymer Nanosheet Films and Their Proton Conduction Mechanism

Mayu Tsuksamoto, Kazuki Ebata, Hiroshi Sakiyama, Shunsuke Yamamoto, Masaya Mitsuishi, Tokuji Miyashita, Jun Matsui

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

We report a biomimetic polyelectrolyte based on amphiphilic polymer nanosheet multilayer films. Copolymers of poly(N-dodecylacrylamide-co-vinylphosphonic acid) [p(DDA/VPA)] form a uniform monolayer at the air-water interface. By depositing such monolayers onto solid substrates using the Langmuir-Blodgett (LB) method, multilayer lamellae films with a structure similar to a bilayer membrane were fabricated. The proton conductivity at the hydrophilic interlayer of the lamellar multilayer films was studied by impedance spectroscopy under temperature- and humidity-controlled conditions. At 60 °C and 98% relative humidity (RH), the conductivity increased with increasing mole fraction of VPA (n) up to 3.2 × 10 -2 S cm -1 for n = 0.41. For a film with n = 0.45, the conductivity decreased to 2.2 × 10 -2 S cm -1 despite the increase of proton sources. The reason for this decrease was evaluated by studying the effect of the distance between the VPAs (l VPA ) on the proton conductivity as well as their activation energy. We propose that for n = 0.41, l VPA is the optimal distance not only to form an efficient two-dimensional (2D) hydrogen bonding network but also to reorient water and VPA. For n = 0.45, on the other hand, the l VPA was too close for a reorientation. Therefore, we concluded that there should be an optimal distance to obtain high proton conductivity at the hydrophilic interlayer of such multilayer films.

Original languageEnglish
Pages (from-to)3302-3307
Number of pages6
JournalLangmuir
Volume35
Issue number9
DOIs
Publication statusPublished - 2019 Mar 5

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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