Monolayers of diacylphosphatidylethanolamines at the air/water interface are studied by grazing incidence X-ray diffraction. The results prove the existence of phases which show analogies with the rotator phases of single-chain surfactants: hexagonal tail lattice with no tilt; rectangular lattice with nearest-neighbour and next-nearest-neighbour tilt; oblique lattices. However, even for very stiff films prepared at low temperatures and for long tail lipids, no structures are found which could be compared with the hindered rotator or crystalline phases. The results indicate that the head/tail mismatch inhibits long-range ordering and that disorder is frozen-in due to the coupling of two tails with one head.
|Journal||Colloids and Surfaces A: Physicochemical and Engineering Aspects|
|Publication status||Published - 1996|