X-RAY SYNCHROTRON STUDY OF PACKING AND PROTRUSIONS OF POLYMER-LIPID MONOLAYERS AT THE AIR-WATER-INTERFACE

Using X-ray scattering, the structure of compressed phospholipid monol ayers at the air-water interface matrixed with varying amounts of poly mer lipid has been determined. The out-of-plane structure of the monol ayer was greatly perturbed by the incorporation of the bulky polymer l ipid resulting in a systematic roughening of the interface and a decre ase in the coherently Bragg-scattering lipid tail region. Our results indicate that the increased lateral packing stresses due to the hydrop hilic polymer chains are predominately relaxed through an increase in lipid protrusions rather than an increased area per lipid molecule.