A. Saintjalmes et al., STRUCTURE OF BIDIMENSIONAL PHOSPHOLIPIDIC CRYSTALLITES ON FORMAMIDE DETERMINED BY X-RAY-DIFFRACTION, Chemical physics letters, 240(1-3), 1995, pp. 234-238
By using grazing incidence X-ray diffraction, we determined the struct
ure of the solid phase of a C-18-C-18 phosphocholine monolayer spread
at the air-formamide interface. The chains are organized on an oblique
lattice, and their tilt, measured from Bragg rod scans, is about 35 d
egrees. No structural change is observed when the surface pressure is
varied from 1 to 38 mN/m. In the solid phase, the area per molecule is
46 Angstrom(2), and the compression modulus is large. The phase stiff
ness is dominated by the interactions between the polar heads and the
formamide, more than between the aliphatic chains.