Freestanding Polyelectrolyte Films as Sensors for Osmotic Pressure

Max-Planck-Institut für Kolloid und Grenzflächenforschung Wissenschaftspark Golm, 14424 Potsdam, Germany.
ChemPhysChem (Impact Factor: 3.42). 09/2006; 7(9):1985-9. DOI: 10.1002/cphc.200600300
Source: PubMed


Freestanding ultrathin polyelectrolyte-multilayer membranes, transferred to topographically structured polydimethylsiloxane (PDMS), are used as mechanical sensors. Due to the membranes' semipermeability, high-molecular-weight molecules can be either entrapped inside them or excluded, thus generating an osmotic pressure. This leads to a deformation. We investigate the deformation as a function of the osmotic pressure and present an analytical theory that fully describes the data. Thus, osmotic pressures can be determined quantitatively. The individual osmotic-sensitive elements have only microscopic dimensions, and arrays can be easily produced.

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