Berlin 2005 – scientific programme

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CPP: Chemische Physik und Polymerphysik

CPP 33: Novel materials I

CPP 33.4: Talk

Wednesday, March 9, 2005, 10:30–10:45, TU C230

Flat freestanding polyelectrolyte films: Fabrication, and applications — •Marc Nolte, Björn Schöler, Claire Peyratout, Dirk Kurth und Andreas Fery — MPI-Kolloid und Grenzflächenforschung, 14424 Potsdam

Ultrathin, semi-permeable membranes are often found in natural systems (membranes of cells or organelles) and they are interesting for applications (separation, filtering). Within artificial membrane systems, polyelectrolyte multilayer membranes can be produced with well defined membrane thickness down to the nm regime and are known to be permeable for low molecular weight molecules while they are impermeable for high molecular weight species. Therefore they are interesting new materials for nanoscale separation membranes. However they are usually solid supported, which limits their use as separation membranes. We present here a novel procedure that allows for producing freestanding membrane patches of polyelectrolyte multilayer membranes with thicknesses down to 50 nm without film rupture or folding, which is commonly observed for other systems. As a result, we can use these membranes for separating arrays of micron sized (this means pico-litre volume) compartments from bulk solution, in which large molecular weight molecules are entrapped. These molecules react to changes of the properties of the external media, because the PE membrane is semipermeable. It is also possible to access single compartments. These both offer the possibility to use those systems for combinatorial chemistry and sensing.