Water droplets exploding during evaporation could revolutionize nanotech

On May 8, researchers from the Okinawa Institute of Science and Technology (OIST) confirmed a phenomenon predicted in 1882 by Lord Rayleigh. Coulomb fission, which describes the violent breakup of charged droplets, was observed on frictionless surfaces for the first time. This discovery could transform electrospray techniques and nanotechnology, making them more efficient and eco-friendly.

The team, led by Professor Dan Daniel, deposited charged water droplets on plastic surfaces coated with silicone oil. The oil layer was essential to eliminate friction, allowing the droplets to change shape and spontaneously fragment. Evaporation concentrated the electric charge, triggering microexplosions that expelled charged microdroplets in microseconds.

This behavior, previously theorized only for suspended droplets, was demonstrated on solid surfaces. Controlling droplet size through oil viscosity offers new opportunities for nanofabrication and chemical analysis.

Lord Rayleigh’s prediction, which set a charge limit for droplet explosion, was validated in a completely new context. Removing friction showed that Coulomb fission physics applies on surfaces, enabling more precise control of the process.

This breakthrough has implications for nano-scale 3D printing and sustainable spray techniques. It could replace traditional high-voltage methods, promoting greener practices in nanotech and chemical analysis.

Starting at KAUST and consolidating at OIST, this research paves the way for more efficient, low-energy electrospray processes. Manipulating charge and droplet size could transform multiple industries in the coming years.