A technique has been developed to fabricate micro- or nanopumps based on
porous alumina thin films. The main body of the nanopump consists of a
porous alumina thin film (containing nano-sized channels of about 40-300
nm in diameter) with conductive surfaces (e.g. Au coating layers) on both
sides of the film. Through the fabrication of nanochannels in (the
alumina films) and the subsequent annealing and surface activation
processes, high-efficiency micro- or nanopumps can be made. The
nanofluidic flow through the nanochannels of the alumina thin films is
driven by an electric field with no moving parts. The flow rate (up to 50
millilitres/(mincm.sup.2)) of water through the alumina thin film can be
continuously tuned through the intensity of the electric field, i.e., the
DC electric potential applied across the nanochannels.