All-Terrain Fluids Move Uphill
11 May 2008, 11:08
Categories: NEMS--MEMS superhydrophobicphilic
Canadian chemists have developed an all-terrain droplet actuation (ATDA) method to move droplets across chips at a wide range of angles. Aaron Wheeler and colleagues at the University of Toronto say digital microfluidic devices using ATDA could be used to move fluids rapidly between different environments, for example to cycle between heating and cooling.
Wheeler developed ATDA on flexible, water-repellent polyimide surfaces, clad with copper, which can be bent into a variety of shapes including steps, twists and overhangs. The fluid beads are moved by sequentially activating a series of electrode pairs, which is thought to pull the droplet forward by reducing water repellence in front of the droplet. This process gives the team full control of the droplet, including up and down vertical surfaces.
To sustain the droplet, a 50 nm thick hydrophobic layer was deposited by spin-coating poly(dimethylsiloxane) (PDMS) (6000 rpm, 1 min) and Teflon-AF1600 (1% resin in Fluorinert FC-40, 2000 rpm, 1 min) on flexible PCB substrates.
Posted by: The Editors
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