Scientists have 3D-printed an all-liquid device that can be repeatedly reconfigured to serve a wide range of applications—from making battery materials to screening drug candidates.
The 3D-printed device can be programmed to carry out multistep, complex chemical reactions on demand, according to researchers from the US Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab).
"What's even more amazing is that this versatile platform can be reconfigured to efficiently and precisely combine molecules to form very specific products, such as organic battery materials," said Brett Helms, a staff scientist in Berkeley Lab, who led the study.
The findings, published in the journal Nature Communications, is the latest in a series of experiments at Berkeley Lab that fabricate all-liquid materials with a 3D printer.
Last year, researchers pioneered a new technique for printing various liquid structures—from droplets to swirling threads of liquid—within another liquid.
"After that successful demonstration, a bunch of us got together to brainstorm on how we could use liquid printing to fabricate a functioning device," Helms said in a statement.
"Then it occurred to us: If we can print liquids in defined channels and flow contents through them without destroying them, then we could make useful fluidic devices for a wide range of applications, from new types of miniaturised chemical laboratories to even batteries and electronic devices," he said.
To make the 3D-printable fluidic device, lead author Wenqian Feng, a postdoctoral researcher in Berkeley Lab, designed a specially patterned glass substrate.
When two liquids—one containing nanoscale clay particles, another containing polymer particles—are printed onto the substrate, they come together at the interface of the two liquids and within milliseconds form a very thin channel or tube about one millimetre in diameter.
Once the channels are formed, catalysts can be placed in different channels of the device.
The user can then 3D-print bridges between channels, connecting them so that a chemical flowing through them encounters catalysts in a specific order, setting off a cascade of chemical reactions to make specific chemical compounds.
When controlled by a computer, this complex process can be automated to execute tasks associated with catalyst placement, build liquid bridges within the device, and run reaction sequences needed to make molecules, said Thomas Russell, a visiting researcher from the University of Massachusetts at Amherst in the US.
The multitasking device can also be programmed to function like an artificial circulatory system that separates molecules flowing through the channel and automatically removes unwanted byproducts while it continues to print a sequence of bridges to specific catalysts, and carry out the steps of chemical synthesis.
"The form and functions of these devices are only limited by the imagination of the researcher," said Helms.
The researchers next plan to electrify the walls of the device using conductive nanoparticles to expand the types of reactions that can be explored.
"With our technique, we think it should also be possible to create all-liquid circuitry, fuel cells, and even batteries," said Helms.
