Optofluidic Characterization of Nanoporous Membranes

RAÚL URTEAGA; LEANDRO N. ACQUAROLI; R.R. KOROPECKI; ABEL SANTOS; MARÍA ALBA; JOSEP PALLARES; LLUIS MARSAL; CLAUDIO L. A. BERLI

LANGMUIR

AMER CHEMICAL SOC

Lugar: Washington; Año: 2013 vol. 29 p. 2784 - 2789

0743-7463

An optofluidic method that accurately identifies the internal geometry of nanochannel arrays is presented. It isbased on the dynamics of capillary-driven fluid imbibition, which is followed by laser interferometry. Conical nanochannel arraysin anodized alumina are investigated, which present an asymmetry of the filling times measured from different sides of themembrane. It is demonstrated by theory and experiments that the capillary filling asymmetry only depends on the ratio H of theinlet to outlet pore radii and that the ratio of filling times vary closely as H^7/3. Besides, the capillary filling of conical channelsexhibits striking results in comparison to the corresponding cylindrical channels. Apart from these novel results in nanoscale fluiddynamics, the whole method discussed here serves as a characterization technique for nanoporous membranes.