Based on an electrochemical approach, the process can be used to fabricate copper objects as small as 25 nanometers in diameter. For reference, an average human hair is around 3000x thicker at 75 microns.
According to the research team led by Dr Dmitry Momotenko, the new 3D printing technique has potential applications in microelectronics, sensor technology, and battery technology.
Adapting electroplating for additive manufacturing
The ETH/NTU nanoprinting approach is actually based on the process of electroplating, a well-known metal coating technique used in the world of manufacturing. To electroplate a part, manufacturers suspend positively charged metal ions in a salt solution. A negatively charged electrode is then added to this liquid solution, which causes the ions to combine with the electrons in the electrode and form neutral metal atoms. The atoms are deposited as a coating on the electrode and slowly form a solid layer on the surface.
Momotenko adds, “In this process, a solid metal is fabricated from a liquid salt solution – a process that we electrochemists can control very effectively.”
The nanoprinting process operates on the exact same premise, whereby a tiny pipette is used to deposit positively charged copper ions onto a negatively charged print surface. In this case, the team used a nozzle tip just 1.6 nanometers wide, meaning only two copper ions could pass through at a time. This, combined with several electrochemical printing parameters, allowed the team to closely control the diameter of the printed structures. The paper reports that the smallest of the printed objects came out at just 25 nanometers wide (195 copper atoms).
On the other hand, conventional powder-based metal 3D printers are typically only capable of reaching micron-level resolutions, which are still several thousand times larger than those in the present study.
“The technology we are working on combines both worlds – metal printing and nanoscale precision,” explains Momotenko.
Applications of metal 3D nanoprinting
Interestingly, Momotenko’s team found that their 3D printing process was able to fabricate a wide variety of object types, including vertical structures, horizontal structures, inclines, and even spirals. The powerful approach lends itself to a whole host of novel applications such as more efficient energy storage devices, microelectronics, and even 3D printed catalysts for chemical production purposes.
As far as future work goes, the researchers are currently working on applying the technique to 3D print more compact lithium-ion batteries. The designs are set to feature increased surface areas on the electrodes and shorter distances between the electrodes, all in a bid to speed up the charging process.
Further details of the study can be found in the paper titled ‘Bringing Electrochemical Three-Dimensional Printing to the Nanoscale’.
The research sphere is often home to some of the most innovative 3D printing techniques around. Back in October, researchers at Loughborough University developed a novel hybrid 3D printing technique that allows them to change the properties of printed parts over time, enabling a new form of 4D printing. Named Material Treatment Extrusion Additive Manufacturing (MaTrEx-AM), the approach combines conventional extrusion-based 3D printing with a chemical treatment.
Elsewhere, at Fraunhofer IWS, scientists revealed the testing of a 3D printing system that could be up to “a thousand times faster” than current mirror-based laser manufacturing technologies. Built around a high-powered 13 KW ‘Dynamic Beam Laser,’ the institute’s setup is said to be capable of rapidly generating different energy distribution patterns, and precisely printing the most demanding of materials.
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Featured image shows the new 3D printing technology. Image via ETH Zurich.