AsianScientist (Nov. 18, 2025) – Leaves have a coating that repels water and protects them fungal and bacterial assaults. However for farmers, this pure coating is a barrier. Once they apply pesticides to guard their crops and crops from pests, half of the pesticides merely run off the leaves.
On the Centre for Nano Science and Engineering on the Indian Institute of Science (IISc), Bengaluru, Rutvik Lathia had been working with liquid marbles — liquid droplets encased in a layer of water-repelling particles — throughout his PhD. At his advisor Prosenjit Sen’s laboratory, he seen one thing surprising: liquid marbles adhere to water-repellent surfaces higher than a naked water droplet. Placing two and two collectively, the group has proposed utilizing liquid marbles as pesticides in a paper revealed within the Journal of Colloid and Interface Science.
“That is counterintuitive and fascinating,” Lathia, who’s now a postdoctoral researcher on the Max Planck Institute for Polymer Analysis, Mainz, Germany, informed Asian Scientist Journal over e-mail, “as in one among our earlier works, we noticed liquid marbles bounce sooner than droplets” on some surfaces which repel water.
At the moment, the pesticide trade is addressing the roll-off drawback in varied methods. One answer is to make use of polymers and oils to extend the stickiness of pesticides, however they’re dangerous to the surroundings. One other is to make use of particular liquids that assist in sticking the pesticides to the leaves however they include ‘surfactants’, which particularly dangerous to honey bees. In keeping with the IISc group, liquid marbles present a biodegradable various that’s, on the identical time, rather more environment friendly at depositing on water-repelling surfaces.
Curiously, the distinction between a water droplet and a liquid marble is skinny — fairly actually — about 35 microns of water-hating materials, like glass, separating them. However the skinny glass layer appears to be making all of the distinction. Whereas water droplets unfold on a water-repelling floor, they recoil sharply, leaving solely about 5 p.c deposited.
However the glass particles, that are water-hating themselves, mark the distinction in property between easy water droplets and liquid marbles. Greater than 95 p.c of the liquid marbles are absorbed. .
Primarily, the distinction boils right down to the absence of recoil, which, as Lathia defined, occurs as a result of the liquid marbles lose 50 p.c of their vitality (in contrast to water droplets) as a result of their inside construction altering in the course of the collision and the glass particles colliding with one another. The collisions enhance friction, just like how automobiles blocking the highway trigger site visitors jams.
However glass beads and Teflon, which researchers usually use within the laboratory to supply liquid marbles, are additionally dangerous to the crops. So, the IISc crew explored various particles which can be biodegradable and natural, reminiscent of lycopodium and zein (a protein present in corn). They confirmed that liquid marbles made with these supplies are extra environment friendly than these utilizing glass bead coating.
Nevertheless, adopting the biodegradable liquid marbles to pesticides isn’t simple.
“The primary problem is scalability,” stated Lathia. It’s not but possible to supply liquid marbles in giant portions at a value comparable to standard spraying. Furthermore, there’s at present no spraying mechanism that may generate liquid marbles with the identical effectivity as normal droplet-based techniques.
The most important bottleneck appears to be understanding the science itself: “We nonetheless want to check how the particle coating influences pesticide uptake by the leaf,” stated Lathia.
That’s not it. The researchers additionally want to determine “whether or not long-term retention of particles impacts plant capabilities reminiscent of photosynthesis or fuel alternate,” he added.
The crew is making an attempt to resolve a number of hurdles. One, concerning the manufacturing: they’re planning to develop a steady setup able to producing giant numbers of liquid marbles with managed dimension and coating.
Two, they are going to take a look at nozzle designs that permit liquid marbles to type immediately throughout spraying. “We additionally intention to establish extra sustainable particle coatings: both supplies that dissolve quickly after deposition or coatings that themselves present pesticidal motion,” Lathia stated.
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Supply: Indian Institute of Science; Pictures: Pijo/Shutterstock
The research might be discovered at: Hydrophobic particle coating for enhanced droplet deposition
