Antiplasticization and water uptake of nafion thin films

Shudipto K. Dishari, Michael A. Hickner

Research output: Contribution to journalArticlepeer-review

74 Scopus citations

Abstract

Fluorescence of 9-(2-carboxy-2-cyanovinyl)julolidine (CCVJ) was measured to probe the local motion within 70-600 nm thick Nafion films at controlled levels of hydration. Thinner films showed increased confinement under dry conditions as evidenced by their high fluorescence intensity values per unit thickness. Antiplasticization, or a stiffening of the film, was observed as an increase in fluorescence intensity when the sample was exposed to low water activity (≤30% RH) and the extent of antiplasticization changed with film thickness. At higher relative humidities, the films became plasticized with water and the fluorescence of CCVJ declined. Quartz crystal microbalance (QCM) experiments revealed higher hydration numbers (λ = nH2O/nSO3H) in thinner films on SiO2 surfaces. The higher water uptake in thin films was explained by considering the polymer order at the Nafion-SiO 2 interface and the influence of this interfacial layer on the swelling properties of thin films.

Original languageEnglish (US)
Pages (from-to)291-295
Number of pages5
JournalACS Macro Letters
Volume1
Issue number2
DOIs
StatePublished - Feb 21 2012
Externally publishedYes

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry

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