Asymmetric capillary filling of nanoporous membranes

CLAUDIO L. A. BERLI; EMANUEL ELIZALDE; RAÚL URTEAGA; R.R. KOROPECKI

Lucca (Barga)

Conferencia; Microfluidics, Physics & Chemistry of; 2013

Gordon Research Conferences

Nanoporous anodized alumina membranes (NAAM) are studied by measuring the dynamics of capillary-driven fluid imbibition on both sides of the substrate by laser interferometry. The membranes considered contain a well-ordered array of straight nanopores with conical geometry. It is found that the filling times present a strong asymmetry depending on which side of the membrane is wet. We show by theory and experiments that, for a given fluid, the asymmetric filling is determined by the ratio of the inlet to outlet pore radii [1]. These novel results in nanoscale fluid dynamics have several potential applications [2]. On the other hand, the optofluidic model used allows one to determine the pore radius variation across the membrane, which is of great interest in the characterization of nanoporous substrates.