MOLECULES ADOPTING AN INVERTED U-SHAPE ON THE WATER-SURFACE BY SELF-ASSEMBLING INTO CRYSTALLINE MONOLAYERS

Model molecules, designed to simulate a chain fold, self-assemble into crystalline monolayers at the air-water interface, the structure of w hich has been determined, in situ, by synchrotron grazing-incidence X- ray diffraction. The two-dimensional packing arrangement in such monol ayers is consistent with a structure composed of ribbons containing tr anslationally related molecules adopting an inverted U-shape. The dist ance between these molecules along the ribbon is optimum for creating an additional chain fold, leading to the possibility that a polymeric molecule will undulate on the water surface.