Examination of fluorination effect on physical properties of saturated long-chain alcohols by DSC and Langmuir monolayer

Hiromichi Nakahara, Shohei Nakamura, Yoshinori Okahashi, Daisuke Kitaguchi, Noritake Kawabata, Seiichi Sakamoto, Osamu Shibata

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

Partially fluorinated long-chain alcohols have been newly synthesized from a radical reaction, which is followed by a reductive reaction. The fluorinated alcohols have been investigated by differential scanning calorimetry (DSC) and compression isotherms in a Langmuir monolayer state. Their melting points increase with an increase in chain length due to elongation of methylene groups. However, the melting points for the alcohols containing shorter fluorinated moieties are lower than those for the typical hydrogenated fatty alcohols. Using the Langmuir monolayer technique, surface pressure (π)-molecular area (A) and surface potential (ΔV)-A isotherms of monolayers of the fluorinated alcohols have been measured in the temperature range from 281.2 to 303.2K. In addition, a compressibility modulus (Cs-1) is calculated from the π-A isotherms. Four kinds of the alcohol monolayers show a phase transition (πeq) from a disordered to an ordered state upon lateral compression. The πeq values increase linearly with increasing temperatures. A slope of πeq against temperature for the alcohols with shorter fluorocarbons is unexpectedly larger than that for the corresponding fatty alcohols. Generally, fluorinated amphiphiles have a greater thermal stability (or resistance), which is a characteristic of highly fluorinated or perfluorinated compounds. Herein, however, the alcohols containing perfluorobutylated and perfluorohexylated chains show the irregular thermal behavior in both the solid and monolayer states.

Original languageEnglish
Pages (from-to)472-478
Number of pages7
JournalColloids and Surfaces B: Biointerfaces
Volume102
DOIs
Publication statusPublished - Feb 1 2013
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Surfaces and Interfaces
  • Physical and Theoretical Chemistry
  • Colloid and Surface Chemistry

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