Miscibility behavior of dipalmitoylphosphatidylcholine with a single-chain partially fluorinated amphiphile in Langmuir monolayers

Takato Hiranita, Shohei Nakamura, Masaki Kawachi, Hélène M. Courrier, Thierry F. Vandamme, Marie Pierre Krafft, Osamu Shibata

Research output: Contribution to journalArticlepeer-review

55 Scopus citations

Abstract

Surface pressure-area, surface potential-area, and dipole moment-area isotherms were obtained for monolayers made from a partially fluorinated surfactant, (perfluorooctyl)undecyldimorpholinophosphate (F8H11DMP), dipalmitoylphosphatidylcholine (DPPC), and their combinations. Monolayers, spread on a 0.15 M NaCl subphase, were investigated at the air/water interface by the Wilhelmy method, ionizing electrode method, and fluorescence microscopy. Surface potentials were analyzed using the three-layer model proposed by Demchak and Fort. The contribution of the dimorpholinophosphate polar head group of F8H11DMP to the vertical component of the dipole moment was estimated to be 4.99 D. The linear variation of the phase transition pressure as a function of F8H11DMP molar fraction (XF8H11DMP) demonstrated that DPPC and F8H11DMP are miscible in the monolayer. This result was confirmed by deviations from the additivity rule observed when plotting the molecular areas and the surface potentials as a function of XF8H11DMP over the whole range of surface pressures investigated. Assuming a regular surface mixture, the Joos equation, which was used for the analysis of the collapse pressure of mixed monolayers, allowed calculation of the interaction parameter (ξ=-1.3) and the energy of interaction (Δε=537 Jmol-1) between DPPC and F8H11DMP. The miscibility of DPPC and F8H11DMP within the monolayer was also supported by fluorescence microscopy. Examination of the observed flower-like patterns showed that F8H11DMP favors dissolution of the ordered LC phase domains of DPPC, a feature that may be key to the use of phospholipid preparations as lung surfactants.

Original languageEnglish (US)
Pages (from-to)83-92
Number of pages10
JournalJournal of Colloid And Interface Science
Volume265
Issue number1
DOIs
StatePublished - Sep 1 2003
Externally publishedYes

Keywords

  • Fluorescence microscopy
  • Fluorinated surfactants
  • Langmuir monolayers
  • Surface dipole moments
  • Surface potentials
  • Two-dimensional phase diagrams π - A isotherm ΔV - A isotherm

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry

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