Structural and electric properties of two semifluorinated alkane monolayers compressed on top of a controlled hydrophobic monolayer substrate.

We investigate the dynamic behavior upon lateral compression of two mixed films made with one of the two semifluorinated alkanes F(CF2)8(CH2)18H and F(CF2)10(CH2)10H and the natural alpha-helix alamethicin peptide. Surface pressure, surface potential versus molecular area isotherms, and grazing-incidence x-ray diffraction were applied to characterize this system. We show that both mixed films demix vertically to form two asymmetric flat bilayers where the lower layer is made of alamethicin and the upper layer is made of semifluorinated molecules.

Assembling and compressing a semifluorinated alkane monolayer on a hydrophobic surface: structural and dielectric properties.

We investigate the dynamic behavior upon lateral compression of a semifluorinated alkane F (CF2)8(CH2)18H (denoted F8H18), spread on the hydrophobic top of a suitable amphiphilic monolayer: namely, a natural alpha-helix alamethicin peptide (alam). We show, in particular, the formation of an asymmetric flat bilayer by compressing at the air-water interface a mixed Langmuir film made of F8H18 and alam. The particular chemical structure of F8H18 , the suitable structure of the underlying alam monolayer and its collapse properties, allow for a continuous compression of the upper F8H18 monolayer while the density of the lower alam monolayer remains constant.