TY  - GEN
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/7426/
KW  - Ionenspurätztechnik 
KW  -  synthetische Nanoporen 
KW  -  Poisson-Nernst-Planck Modellsynthetic nanopores 
KW  -  ionic transport 
KW  -  Poisson-Nernst-Planck model 
KW  -  ion track-etching 
KW  -  polymer 
KW  -  biosensor
A1  - Schiedt, Birgitta
Y1  - 2007///
AV  - public
ID  - heidok7426
TI  - Characterization and application of ion track-etched nanopores
N2  - This thesis investigates the ionic transport properties of single, conical nanopores in polymers, as well as their applicability as single-molecule sensors. The pores were produced by selective etching of the damaged zones of energetic heavy ions (track-etching technique). More basic investigations of the shape of track-etched pores (by small-angle X-ray scattering, electron microscopy and conductometry) are also included, revealing smaller pore sizes on top of a membrane than inside the pore. Conical track-etched nanopores are cation selective and show asymmetric I-V characteristics, depending on pH value and concentration of the electrolyte. These properties result from their negative surface charges created during the etching process, which lead to an intrinsic asymmetric electric potential long the pore axis. Experiments show a maximum for the rectification at about 0.1 M KCl, in accordance with theoretical calculations. The selectivity of the pores depends on the direction of an applied concentration gradient, being higher for the lower concentration facing the small opening of the pore, again in agreement with calculations. The pores transport properties are strongly influenced by small concentrations of divalent cations. Conical polyimide pores have been found suitable to detect single DNA molecules passing through them via changes in the ionic current.
ER  -