Drops on the networks
Her drops made the headlines of the journal Soft Matter, published on 28 September 2015 (1). But what’s so special about them? They’re the first of their kind to have been created using a simple and flexible method. And pharmacists and chemists already have big plans for these microscopic droplets.
A fishing line network
The different water droplets have to be created first. To achieve this, the researcher used a fibre network made from nylon fishing line. In principle, placing a drop on a fibre isn’t very difficult, you just need a syringe. But this method can’t be used for the very small volumes sought after in microfluidics. “In this case, you have to resort to fibre networks”, explains Floriane Weyer. “When a drop reaches the point where two threads cross, if its volume is sufficiently great, it passes through the node, which doesn’t retain it, and it continues on its way. But as it does so, it deposits a small residue around the node, which is far smaller than the initial drop. We studied the formation of these water droplets around nodes, as well as their geometry, volume, etc.”
(1) F.Weyer, M.Lismont, L.Dreesen and N.Vandewalle, Compound droplet manipulations on fiber arrays, Soft Matter, 2015, 11, 7086.