Nanoscale 3D Printing Is Edging Closer to Reality

Nanoscale 3D printing is the ability to 3D print objects measured in nanometers. As an example, there are 1,000,000 nanometers in 1 millimeter. To better understand the size or lack thereof, we should reference the size of one human hair, which is 75,000-100,000 nanometers in diameter.

Exploring nano-scale 3D printing

This microscopic scale host's an array of potential industry-disrupting products, from smaller computer chips and 1 pc printed computer boards to nanoscale metal parts that give way to faster charging/discharging abilities for batteries.

This breakthrough will both improve efficiency and increase the productivity of smaller parts.

Industries like microelectronics, nanorobotics, and sensor technologies stand to benefit from the ability to create on such a nanoscale without compromising accuracy. At this time universities across America are researching different ways to print at a nano-scale while retaining the accuracy their respective industries require.

Several of these institutes are focusing on advancements in electrical technologies while others have their eyes set on nano-printing methods that utilize photochemical reactions including the immobilization of proteins, glycans, or genes. 

Nanoscale printed synthetic materials and plastics have long benefited from the ability to print at this scale, it is only in the preceding 2-3 years that scientists have made breakthroughs in printing metal objects accurately to this size.

3D printing metal at this scale enables scientists to assemble an object atom by atom. 

Nanoscale 3D printing solutions 

Dr. Dmitry Momotenko, who leads the junior research group at the Institute of Chemistry, believes this technology will allow his team to 3D print batteries that can recharge and discharge at rates in excess of 1000x faster than current competing technologies. Some of his statements include: “If that can be achieved today EV'S can be charged within seconds”.

The goal is to exponentially shorten the pathways between ion's in the battery cell. Nanoscale 3D printing will allow his team to revisit this 20-year-old idea in hopes of being able to 3d print batteries' internal structures in a manner that allows electrons to pass through the entire cell at once, versus having to pass through from one side of the cell to the other.

With the ability to accurately print metal structures down to 25 microns both nanorobotics (nanoscale microchips) and microelectronics stand to equally benefit from this technology.

Nanoscale 3D printer technologies 

Chemist Liaisan Khasanova at the University of Oldenburg is tasked with creating the specialized nozzle tip required to print at nanoscale. Starting with an ordinary silica glass tube, a 1mm thick capillary tube is inserted with a blue liquid. Once electricity is applied a reaction takes place resulting in a loud bang. The tube is then removed revealing a hole small enough to meet their requirements. “A laser beam inside the device heats up the tube and pulls it apart. Then we suddenly increase the tensile force so that the glass breaks in the middle and a very sharp tip forms,” explains Khasanova, who is working on her Ph.D. in chemistry in the Electrochemical Nanotechnology Group at the University of Oldenburg, Germany.

At the University's Wechloy campus, the lab features 3 printers that are built and programmed in-house to their exacting standards. Similar in concept to today's consumer 3D printers, but with one small difference – the size.

These printers focus on accuracy, utilizing large granite bases layered with foam to assist in the reduction of vibrations created by the printing process. These steps assist in precisely controlling the 3D printer resulting in higher accuracy at smaller scales. Conventional powder-based metal 3D printers are only capable of micron-level resolutions, a size difference of 1000x.  

The printer's environment is also factored in, the team has taken the lights in their laboratory into consideration due to electromagnetic interference. They use battery-powered lights to help isolate the electromagnetic field generated by alternating currents.

A small look at metal nanostructures

Nano-scale printed plastic molecules are easily manipulated into structural shapes given their lack of strength and lower heat tolerances. The malleable nature of plastic offers scientists the ability to manipulate the plastic into smaller shapes. This ease of use has resulted in most of the recent advancements in printing technology.

In comparison, metal nanoscale 3D printing requires tighter tolerances and higher resistance to both heat and wear. These printers required recent advancements from refined printing algorithms to re-invented printer tips to enable small accurate prints. 

Currently, the team is able to work with copper, silver, nickel, nickel-manganese, and nick-cobalt alloys. Dr. Momotenko and a team of researchers were successful in creating copper spiral columns 25 nanometers or 195 copper atoms in size as part of their studies published in the Journal of Nanotechnologies in 2021. Utilizing a method created by Dr. Momotenko and his colleague Julian Hengsteler, a feedback mechanism is used in conjunction with the extrusion head in to mediate the retraction process required to prevent the nozzle from solidifying mid-print. Prints take shape one layer at a time at speeds of a few nanometers per second. 

Time is of the essence

Printing flat spiral objects lends well to the advancements of battery storage and production. It controls the nanostructures in a way that allows the protons to pass through the battery quickly and evenly. This results in enhanced batteries charge rates and discharge rates.

This will benefit industries reliant on energy storage, from EV batteries, to off-grid homes, or the storage requirements of data server farms that can never go offline due to a power grid failure.

First comes risk

To mitigate the risks associated with the production of lithium-ion batteries, specialized sealed chambers are filled with a positive pressure inert argon gas. Sized to host the printer in an inert environment, the chamber is 10 feet long and weights nearly 1000 lbs.

How will the battery manage the heat produced by its reaction when it is charged to full capacity? “On the one hand, we are working on the chemistry needed to produce active electrode materials at the nanoscale; on the other, we are trying to adapt the printing technology to these materials,” says Dr. Momotenko.

Then comes progress

Relying on existing electroplating technologies they were able to adapt this method (positive charged copper ions with a negative charged electrode inside the salt solution). The extrusion tip the team developed has allowed them to 3D print at nanoscale, compared to current powder-based 3D printers that are limited to microns.

Battery technology is only the first use case, Dr. Momotenko has other bold concepts in mind. He plans to use this printing technology to capitalized on a younger field called spintronics, which targets the ability to manipulate “spin” – a quantum mechanical property of electrons.

He also plans to manufacture sensors capable of detecting individual molecules. This would assist in detecting Alzheimer's, notorious for its fractional amounts of biomarkers. 

Even after developing this technology, the team remains in awe of the ability to create objects the human eye is incapable of seeing without assistance.