Berlin 2001 – scientific programme
Parts | Days | Selection | Search | Downloads | Help
CPP: Chemische Physik und Polymerphysik
CPP 19: Poster: New Methods, Thin Polymer Films, Monolayers
CPP 19.27: Poster
Thursday, April 5, 2001, 12:30–15:00, AT1
Structure and Superstructure within Lipopolymeric Monolayers — •Heiko Ahrens1, Thomas Rosleff Baekmark2, Rudolf Merkel2, Karlheinz Graf1, Roberto Raiteri3, and Christiane A. Helm1 — 1Universität Greifswald, Angewandte Physik, D-17487 Greifswald — 2TU München, Physik Department E22, D-85748 Garching — 3Universität Genua, Department of Biophysical and Electronic Engineering, I-16415 Genova
For the first time, the formation and growth of a molecular superstructure within a lipopolymeric monolayer on the water surface is directly observed by small-angle GID-diffraction. Nanoscopic stripes of weakly ordered alkyl chains (6 nm wide) and solubilized polymer alternate, due to an equilibrium between strong short-ranged attraction and weak long-ranged polymeric repulsion. This structure can be reversibly induced by adjusting the temperature and molecular area. At the onset of the superstructure formation, the smallest stripe periodicity is measured. Then the periodicity relaxes (up to 17 nm), even if the monolayer is further compressed. This threshold behavior is attributed to a very high local pressure necessary for stripe alignment. On solid substrates, the superstructure periodicity is decreased down to 12 nm due to dehydration of the polymer moieties.