MIT Researchers Use 3D Printing to Democratize the Production of Electrospray Emitters

Researchers at the Massachusetts Institute of Technology (MIT) have created low-cost electronic nozzles, called triaxial electrospray emitters, via 3D printing. Traditionally, producing these devices requires days inside a multi-million-dollar semiconductor “cleanroom” (the same high-tech facilities where computer chips are made). Now, the MIT team hopes their 3D printable design will democratize the process. But what exactly do these devices do, and why are they important?

To understand the value of electrospray emitters, you first have to understand how they work. Imagine a standard spray bottle. When you squeeze the trigger, it forces liquid through a tiny hole, creating a mist of droplets. An electrospray emitter is like an advanced, microscopic spray nozzle. But instead of using physical pressure to squirt liquid, it uses electricity. By applying a high voltage to the liquid as it flows out of a microscopic tip, the electrical force pulls and shatters the liquid into a steady stream of tiny, identical droplets. Because it uses electricity, it can make droplets much smaller, faster, and more uniformly than a normal mechanical nozzle.

A close-up look at the electrospray nozzles

The Role of 3D Printing in Triaxial Emitter Production

The device that the MIT team designed is unique: the researchers could not find any previous reports of a miniaturized triaxial electrospray array in the open literature. The electrospray array is about one square centimeter and contains a network of internal, coiled channels feeding 16 perfectly uniform nozzles. “Triaxial” refers to each nozzle having three concentric nozzles, that are nested inside one another. When this device runs, it shoots out three non-mixable liquids at the exact same time, forming a perfect layered droplet.