UC Irvine

Nanopores and micropores are of great interest as tools in biomimetics and biotechnology. Pores used in this study were prepared by the track-etching technique in polymer foils of polyethylene terephthalate and polycarbonate. Opening diameter of these pores can be tuned from a few nanometers up to tens of micrometers. Nanopores in polyethylene terephthalate were used as a model system for understanding hydrophobic interactions at the nanoscale. Walls of these pores were decorated with alkyl chains of varying length between three and ten carbon atoms. We show that hydrophobic interactions are not only tuned by the pore opening diameter, but also type of chemical modification and electrolyte ionic strength. More concentrated solutions favored wetting of the pores so that finite ion current could be recorded. We also used micrometer sized pores in polyethylene terephthalate and polycarbonate pores as a tool for detecting microspheres and biological cells. We focused on the influence of local diameter undulations of the pores on the object transport. We found that rough forms feature local pressure gradients, which can be used to probe mechanical properties of translocating objects. Potential application of such pores for detecting circulating tumor cells is discussed.