Posts belonging to Category 2D printing

Mini Flying Machines

Tiny floating robots could be useful in all kinds of ways, for example, to probe the human gut for disease or to search the environment for pollutants. In a step toward such devices, researchers describe a new marriage of materials, combining ultrathin 2-D electronics with miniature particles to create microscopic machines. The researchers will present their work today at the 255th National Meeting & Exposition of the American Chemical Society (ACS). The meeting features more than 13,000 presentations on a wide range of science topics.

A schematic diagram of a microscopic chemical detection machine depicting a micrometer-sized polymer particle coated with a nanoelectronic circuit.

You can make electronic circuits that are a single atom thick, which is just insanely thin,” Michael Strano, Ph.D., says. “One creative use no one has thought of until now is taking these electronics and grafting them onto a colloidal particle. The particle, which can float in the air like a speck of dust, has simple computing functions. You can bring these new electronics to environments they otherwise could not access.

As a first step, the researchers needed to develop a compatible set of electronic components for the particle’s coating to form a closed autonomous circuit. “This was difficult to do,” says Volodymyr Koman, Ph.D., a research fellow in Strano’s group at Massachusetts Institute of Technology. “We went through a number of different devices to meet certain power and energy requirements.” In the end, Strano’s team selected a biocompatible material, SU-8, for the micrometer-sized particles and lithographically etched them to create a closed circuit consisting of a power source, a detector and a memory device.

The researchers envision a range of uses for these miniature flying machines. Monitoring large areas for bacteria, spores, smoke, dust or toxic fumes currently requires enormous resources, Koman says. Satellites or a fleet of flying drones can do these tasks but they are expensive, while on-the-ground sensors require labor-intensive installation, which is often slow in comparison to the aerosol spreading velocity. “As an alternative, we introduce the concept of an aerosolizable electronic device,” he says. As one example, the researchers tested the tiny devices in a simulated gas pipeline. The flying machines successfully sailed through the test chamber and detected the presence of carbon particulates or volatile organic compounds along the way and stored this information in memory.


Electronics: Printing of flexible, stretchable silver nanowire circuits

Researchers at North Carolina State University ( NC State) have developed a new technique that allows them to print circuits on flexible, stretchable substrates using silver nanowires. The advance makes it possible to integrate the material into a wide array of electronic devices.

Silver nanowires have drawn significant interest in recent years for use in many applications, ranging from prosthetic devices to wearable health sensors, due to their flexibility, stretchability and conductive properties. While proof-of-concept experiments have been promising, there have been significant challenges to printing highly integrated circuits using silver nanowires. Silver nanoparticles can be used to print circuits, but the nanoparticles produce circuits that are more brittle and less conductive than silver nanowires. But conventional techniques for printing circuits don’t work well with silver nanowires; the nanowires often clog the printing nozzles.

Our approach uses electrohydrodynamic printing, which relies on electrostatic force to eject the ink from the nozzle and draw it to the appropriate site on the substrate,” says Jingyan Dong, co-corresponding author of a paper on the work and an associate professor in NC State’s Edward P. Fitts Department of Industrial & Systems Engineering. “This approach allows us to use a very wide nozzle – which prevents clogging – while retaining very fine printing resolution.” “And because our ‘ink’ consists of a solvent containing silver nanowires that are typically more than 20 micrometers long, the resulting circuits have the desired conductivity, flexibility and stretchability,” says Yong Zhu, a professor of mechanical engineering at NC State and co-corresponding author of the paper.

In addition, the solvent we use is both nontoxic and water-soluble,” says Zheng Cui, a Ph.D. student at NC State and lead author of the paper. “Once the circuit is printed, the solvent can simply be washed off.” What’s more, the size of the printing area is limited only by the size of the printer, meaning the technique could be easily scaled up.

The researchers have used the new technique to create prototypes that make use of the silver nanowire circuits, including a glove with an internal heater and a wearable electrode for use in electrocardiography. NC State has filed a provisional patent on the technique.


Flexible, Low-Cost, Water-Repellent Gaphene Circuits

New graphene printing technology can produce electronic circuits that are low-cost, flexible, highly conductive and water repellent. The nanotechnology “would lend enormous value to self-cleaning wearable/washable electronics that are resistant to stains, or ice and biofilm formation,” according to a recent paper describing the discovery.

“We’re taking low-cost, inkjet-printed graphene and tuning it with a laser to make functional materials,” said Jonathan Claussen, an Iowa State University assistant professor of mechanical engineering, an associate of the U.S. Department of Energy’s and the corresponding author of the paper recently featured on the cover of the journal Nanoscale. The paper describes how Claussen and the nanoengineers in his research group use to create electric circuits on flexible materials. In this case, the ink is flakes of graphene – the wonder material can be a great conductor of electricity and heat, plus it’s strong, stable and biocompatible.

And now they’ve found another application of their laser processing technology: taking graphene-printed circuits that can hold water droplets (they’re hydrophilic) and turning them into circuits that repel water (they’re superhydrophobic).

We’re micro-patterning the surface of the inkjet-printed graphene,” Claussen said. “The laser aligns the graphene flakes vertically – like little pyramids stacking up. And that’s what induces the hydrophobicity.” Claussen said the energy density of the laser processing can be adjusted to tune the degree of hydrophobicity and conductivity of the printed graphene circuits. And that opens up all kinds of possibilities for new electronics and sensors, according to the paper. “One of the things we’d be interested in developing is anti-biofouling materials,” said Loreen Stromberg, a paper co-author and an Iowa State postdoctoral research associate in mechanical engineering and for the Virtual Reality Applications Center. “This could eliminate the buildup of biological materials on the surface that would inhibit the optimal performance of devices such as chemical or biological sensors.”

The technology could also have applications in flexible electronics, washable sensors in textiles, microfluidic technologies, drag reduction, de-icing, electrochemical sensors and technology that uses graphene structures and electrical simulation to produce stem cells for nerve regeneration. The researchers wrote that further studies should be done to better understand how the nano– and microsurfaces of the printed graphene creates the water-repelling capabilities. .

The Iowa State University Research Foundation is working to patent the technology and has optioned it to an Ames-based startup, NanoSpy Inc., for possible commercialization. NanoSpy, located at the Iowa State University Research Park, is developing sensors to detect salmonella and other pathogens in food processing plants. Claussen and Stromberg are part of the company.


Printed 3D Nanostructures Against Counterfeiting

Security features are to protect bank notes, documents, and branded products against counterfeiting. Losses caused by product forgery and counterfeiting may be enormous. According to the German Engineering Association, the damage caused in 2016 in its branch alone amounted to EUR 7.3 billion. In the Advanced Materials Technologies journal, researchers of Karlsruhe Institute of Technology (KIT) and the ZEISS company now propose to use printed 3D microstructures instead of 2D structures, such as holograms, to improve counterfeit protection.

Today, optical security features, such as holograms, are frequently based on two-dimensional microstructures,” says Professor Martin Wegener, expert for 3D printing of microstructures at the Institute of Nanotechnology of KIT. “By using 3D-printed fluorescent microstructures, counterfeit protection can be increased.” The new security features have a side length of about 100 µm and are barely visible with the eye or a conventional microscope. For their production and application, Wegener and his team have developed an innovative method that covers all processes from microstructure fabrication to the readout of information.

The microstructures consist of a 3D cross-grid scaffold and dots that fluoresce in different colors and can be arranged variably in three dimensions within this grid. To produce and print such microstructures, the experts use a rapid and precise laser lithography device developed and commercialized by the Nanoscribe company, a spinoff of KIT. It enables highly precise manufacture of voluminous structures of a few millimeters edge length or of microstructured surfaces of several cm² in dimension. The special 3D printer produces the structures layer by layer from non-fluorescent and two fluorescent photoresists. A laser beam very precisely passes certain points of the liquid photoresist. The material is exposed and hardened at the focus point of the laser beam. The resulting filigree structure is then embedded in a transparent polymer in order to protect it against damage.


Polymeric Materials Outperform Natural Antibodies

Experts from the Biotechnology Group led by Professor Sergey Piletsky at the University of Leicester (UK) in collaboration with the spin-off company MIP Diagnostics Ltd, have announced the development of polymeric materials with molecular recognition capabilities which hold the potential to outperform natural antibodies in various diagnostic applications.

chemical background

 In a newly released article ‘A comparison of the performance of molecularly imprinted polymer nanoparticles for small molecule targets and antibodies in the ELISA format’ the researchers successfully demonstrated that polymer nanoparticles produced by the molecular imprinting technique (MIP nanoparticles) can bind to the target molecule with the same or higher affinity and specificity than widely used commercially available antibodies and against challenging targets.

Additionally, their ease of manufacture, short lead time, high affinity and the lack of requirement for cold chain logistics make them an attractive alternative to traditional antibodies for use in immunoassays.

Professor Piletsky, from our Department of Chemistry, explained: “It is now well over twenty years since the first demonstration that molecularly imprinted polymers can be used as the recognition material in assays for clinically significant drugs“. 


3D Printed Concrete Bridge

Today world’s first 3D printed reinforced, pre-stressed concrete bridge was opened. The cycle bridge is part of a new road around the village of Gemert, in the Netherlands. It was printed at Eindhoven University of Technology. With the knowledge the researchers gained in this project, they are now able to design even larger printed concrete structures.
The bridge is the first civil infrastructure project to be realized with 3D-concrete printing. The bridge is 8 meters long (clear span 6.5 meters) and 3.5 meters wide. As it is a ‘worlds first’, the developers did not take any chances and tested the bridge by putting a load of 5 tons on it, which is a lot more than the load the bridge will actually carry.


The bridge has to meet all regular requirements of course. It is designed to do its duty – to carry cyclists – for thirty years or more. With more cycles than people in the Netherlands, it is expected that hundreds of cyclists will ride over the printed bridge every day. It is part of a large road construction project, led by the company BAM Infra, and commissioned by the province of North-Brabant.
An important detail is that the researchers at Eindhoven University of Technology have succeeded in developing a process to incorporate steel reinforcement cable while laying a strip of concrete. The steel cable is the equivalent of the reinforcement mesh used in conventional concrete. It handles the tensile stress because concrete cannot deal with tensile stress adequately, but steel can.
One of the main advantages of printing concrete is that much less concrete is needed than in the conventional technique, in which a mold (formwork) is filled with concrete. By contrast, the printer deposits only the concrete where it is needed, which decreases the use of cement. This reduces CO2 emissions, as cement production has a very high carbon footprint.

Another benefit lies in the freedom of form: the printer can make any desired shape, whereas conventional concrete shapes tend to be unwieldy in shape due to use of formwork. Concrete printing also enables a much higher realization speed. No formwork structures have to be built and dismantled, and reinforcement mesh does not have to be put in place separately. Overall, the researchers think the realization will eventually be roughly three times faster than conventional concrete techniques.


Move And Produce Electricity To Power Your Phone

Imagine slipping into a jacket, shirt or skirt that powers your cell phone, fitness tracker and other personal electronic devices as you walk, wave and even when you are sitting down. A new, ultrathin energy harvesting system developed at Vanderbilt University’s Nanomaterials and Energy Devices Laboratory has the potential to do just that. Based on battery technology and made from layers of black phosphorus that are only a few atoms thick, the new device generates small amounts of electricity when it is bent or pressed even at the extremely low frequencies characteristic of human motion.


In the future, I expect that we will all become charging depots for our personal devices by pulling energy directly from our motions and the environment,” said Assistant Professor of Mechanical Engineering Cary Pint, who directed the research.
This is timely and exciting research given the growth of wearable devices such as exoskeletons and smart clothing, which could potentially benefit from Dr. Pint’s advances in materials and energy harvesting,” observed Karl Zelik, assistant professor of mechanical and biomedical engineering at Vanderbilt, an expert on the biomechanics of locomotion who did not participate in the device’s development.

Doctoral students Nitin Muralidharan and Mengya Lic o-led the effort to make and test the devices. When you look at Usain Bolt, you see the fastest man on Earth. When I look at him, I see a machine working at 5 Hertz, said Muralidharan.

The new energy harvesting system is described in a paper titled “Ultralow Frequency Electrochemical Mechanical Strain Energy Harvester using 2D Black Phosphorus Nanosheets” published  by the journal ACS Energy Letters.


Perovskite Solar Cells Conversion Efficiency Rises Up To 20%

A new low-temperature solution printing technique allows fabrication of high-efficiency perovskite solar cells with large crystals intended to minimize current-robbing grain boundaries. The meniscus-assisted solution printing (MASP) technique boosts power conversion efficiencies to nearly 20 percent by controlling crystal size and orientation.

The process, which uses parallel plates to create a meniscus of ink containing the metal halide perovskite precursors, could be scaled up to rapidly generate large areas of dense crystalline film on a variety of substrates, including flexible polymers. Operating parameters for the fabrication process were chosen by using a detailed kinetics study of perovskite crystals observed throughout their formation and growth cycle.

We used a meniscus-assisted solution printing technique at low temperature to craft high quality perovskite films with much improved optoelectronic performance,” said Zhiqun Lin, a professor in the School of Materials Science and Engineering at the Georgia Institute of Technology. “We began by developing a detailed understanding of crystal growth kinetics that allowed us to know how the preparative parameters should be tuned to optimize fabrication of the films.”

The new technique is reported in the journal Nature Communications.


3-D Printed Graphene Foam

Nanotechnologists from Rice University and China’s Tianjin University have used 3-D laser printing to fabricate centimeter-sized objects of atomically thin graphene. The research could yield industrially useful quantities of bulk graphene and is described online in a new study in the American Chemical Society journal ACS Nano.

Laser sintering was used to 3-D print objects made of graphene foam, a 3-D version of atomically thin graphene. At left is a photo of a fingertip-sized cube of graphene foam; at right is a close-up of the material as seen with a scanning electron microscope

This study is a first of its kind,” said Rice chemist James Tour, co-corresponding author of the paper. “We have shown how to make 3-D graphene foams from nongraphene starting materials, and the method lends itself to being scaled to graphene foams for additive manufacturing applications with pore-size control.”

Graphene, one of the most intensely studied nanomaterials of the decade, is a two-dimensional sheet of pure carbon that is both ultrastrong and conductive. Scientists hope to use graphene for everything from nanoelectronics and aircraft de-icers to batteries and bone implants. But most industrial applications would require bulk quantities of graphene in a three-dimensional form, and scientists have struggled to find simple ways of creating bulk 3-D graphene.

For example, researchers in Tour’s lab began using lasers, powdered sugar and nickel to make 3-D graphene foam in late 2016. Earlier this year they showed that they could reinforce the foam with carbon nanotubes, which produced a material they dubbed “rebar graphene” that could retain its shape while supporting 3,000 times its own weight. But making rebar graphene was no simple task. It required a pre-fabricated 3-D mold, a 1,000-degree Celsius chemical vapor deposition (CVD) process and nearly three hours of heating and cooling.  “This simple and efficient method does away with the need for both cold-press molds and high-temperature CVD treatment,” said co-lead author Junwei Sha, a former student in Tour’s lab who is now a postdoctoral researcher at Tianjin. “We should also be able to use this process to produce specific types of graphene foam like 3-D printed rebar graphene as well as both nitrogen- and sulfur-doped graphene foam by changing the precursor powders.” Sha and colleagues conducted an exhaustive study to find the optimal amount of time and laser power to maximize graphene production. The foam created by the process is a low-density, 3-D form of graphene with large pores that account for more than 99 percent of its volume.

The 3-D graphene foams prepared by our method show promise for applications that require rapid prototyping and manufacturing of 3-D carbon materials, including energy storage, damping and sound absorption,” said co-lead author Yilun Li, a graduate student at Rice.


Metal 3D Printing Withstands Extreme Pressure And Heat

3D printed metal turbine blades able to withstand extreme pressure have been successfully tested by Siemens. It opens the way to develop high pressure components for power generators and other industries, such as aeronautics. These blades can survive temperatures above 1,250 Celsius and pressures similar to the weight of a double-decker bus.


“To have this rotating part running is a breakthrough because it is submitted to these extreme loading… It rotates with 13,600 rotations-per-minute which means it is the most highly loaded component in the whole gas turbine. So this blade that weighs 180 grams will weigh 11 tonnes while rotating with this speed,” says Jenny Nilsson, Team leader for additive manufacturing at Siemens.

Last year Siemens bought British-based Material Solutions, where the metal-based printing is being perfected. A computer-aided design model is first sent to one of these machines. Precision lasers are then fired at a thin layer of metal powder.

This is the nickel superalloy powder. This metallic powder is deposited in 20 micron layer thickness and then the laser melts the part,“explains Clotilde Ravoux, system engineer at Material Solutions.

Ultra-thin layers are added one by one, building up the part. Testing is ongoing and Siemens can’t say when these blades will be commercially produced. But they say it reduces the design-to-testing time from years to months.  “When you apply casting procedures you will probably take one to one and a half years to provide you with these blades because of their long lead-time for tooling. And by applying additive manufacturing we could significantly shorten lead time by down to three months,” adds  Christoph Haberland, manufacturing engineering.

General Electric introduced its first 3D-printed aircraft engine component into service last July. While Boeing is using metal-based 3D printing to drastically cut the production costs of its 787 Dreamliner.


3D Printing Art And Design in Paris

Do you plan  to travel to Paris? In this case do not miss to visit the Centre Pompidou,  this huge museum, located in the center of Paris and dedicated to modern Art.  You can assist to  “Mutations/Créations“: a new event decidedly turned towards the future and the interaction between digital technology and creation; a territory shared by art, innovation and science.


Drawing on all the disciplines in a mix of research, art and engineering, the first edition of this annual event calls upon music, design and architecture. It consists of two exhibitions (“Imprimer le monde“ and “Ross Lovegrove“), an Art/Innovation Forum entitled “Vertigo“, and various study days and get-togethers. Each year, thematic and monographic exhibitions will be staged around meetings and workshops that turn the Centre Pompidou into an “incubator“: a place for demonstrating prototypes, carrying out artistic experiments in vivo, and talking with designers. This platform will also be a critical observatory and a tool for analysing the impact of creation on society. How have the various forms of creation begun using digital technologies to open up new industrial perspectives? How do they question the social, economic and political effects of these industrial developments, and their ethical limits? What formal transformations have come about in music, art, design and architecture with regard to technical and scientific progress?

In the same space,  you can see a  new retrospective devoted to British designer Ross Lovegrove, which shows how the artist has introduced a fresh dialogue between nature and technology, where art and science converge. He employs a “holistic“ idea of design through a visionary practice that began incorporating digital changes during the 1990s, rejecting the productivism of mass industry and replacing it with a more economical approach to materials and forms. This exhibition emphasises the role of design in the postindustrial era, now that we are seeing a significant shift from mechanics to organics: a changeover symptomatic of our times, which these “digital forms“ endeavour to highlight.


College Student 3D Prints His Own Braces

Amos Dudley wears his skills in his smile. The digital design major has been straightening his top teeth for the past 16 weeks using clear braces he made himself.


 “I’m still wearing the last one,” said Dudley . “The last one” refers to the twelfth and final straightening tray in his self-designed treatment. Dudley said he had braces when he was in junior high, but he didn’t wear his retainer as much as he should have, and his teeth shifted. Over time, Dudley discovered that he wasn’t smiling as much because he wasn’t happy with the way his teeth looked.

Name brand options for clear braces can cost up to $8,000, according to companies like Invisalign, Damon, and ClearCorrect. But the 24-year-old wanted to save money, so he found a way to manufacture his own for less than $60. The total cost is so low because he only had to pay for materials used to make the models of his teeth and the retainers. Even though he built his own 3D printer at home, he opted to use a high-end and more precise 3D printer at his school, New Jersey Institute of Technology.

He used NJIT’s equipment to scan and print models of his teeth, and mold non-toxic plastic around them to form the set of 12 clear braces. Dudley determined out how far he needed to move his teeth to correct the misalignment problems. Then divided it by the maximum recommended distance a tooth should travel to determine the design for each alignment tray. Orthodontists use a similar process. Researching the materials he needed and figuring out how teeth move was the most difficult part of Dudley’s orthodontic adventure. The most exciting was when he finally put the first aligner in his mouth. “It was very obvious which tooth [the tray] was putting pressure on,” he said. “I was sort of worried about accumulated error, but that wasn’t the case so that was a pretty glorious moment.