Regensburg 2010 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 16: Organic, polymeric, biomolecular films - also with adsorbates
O 16.10: Vortrag
Montag, 22. März 2010, 17:15–17:30, H46
Crystalline Inverted Membrane Growth by Electrospray Ion Beam Deposition — •Stephan Rauschenbach1, R. Thomas Weitz1, Ludger Harnau2, Nikola Malinowski1,3, Theresa Lutz1, Nicha Thontasen1, Zhitao Deng1, and Klaus Kern1,4 — 1MPI Festkoerperforschung, Stuttgart, Germany — 2MPI Metallforschung, Stuttgart, Germany — 3Central Laboratory of Photographic Processes, Bulgarian Academy of Sciences, Sofia, Bulgaria — 4Institut de la Matière Condenseé, EPFL, Lausanne, Switzerland
Amphiphilic molecules assembled in 2D membranes stabilize interfaces by the interplay of intermolecular- and hydrophobic- interactions. The latter interaction is canceled, when the surfactant molecules are transferred to an interface in vacuum.
Ion beam deposition of sodium dodecyl-sulfate (SDS) onto surfaces in vacuum is used as a model system for the assembly of amphiphilic molecules in the absence of solvents. To this end, cluster ion beams of SDS with excess Na+ as charge carrier are deposited on graphite and silicon samples which are analyzed ex-situ by AFM.
Our samples show stable, extended, flat islands of heights corresponding to single and double layers of upright standing SDS molecules. The relative strengths of the ionic- and van-der-Waals-interaction between the molecules without the presence of water suggests an inverted internal structure of the membranes with respect to their liquid grown counterparts. The shape of the islands is found to be characteristic for a crystalline phase of SDS.