The controlled assembly of nanowires is essential for nanoscale processes. The dielectrophoretic (DEP) assembly process enables a very simple and efficient assembly; however, controlling the number and dimension of nanowires to bridge electrodes is extremely intricate. The micromachined nanowire diluter presented in this paper can automatically dilute and sort nanowires in solution without requiring conventional centrifuge equipment. The device consists of a glass substrate with an array of gold electrode pairs and a PDMS microchannel. Nickel nanowires (30 μm-long) were fabricated by a template-directed electrodeposition process using nanoporous alumina templates. A liquid solution containing nanowires was injected into an inlet of the diluter. Pulsed voltages were applied to 16 pairs of electrodes. The nanowires were subsequently trapped or released in the microchannel at specific pulsed electric fields. As a result, the number of nanowires at the outlet of the channel was dramatically reduced, implying that the device presented here can effectively dilute nanowire suspensions for controlled assembly.
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