Tag Archives: flexible

Repelling liquid with superomniphobic tape

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The Kota lab at Colorado State University has created a superomniphobic tape that adheres to any surface and imparts liquid-repellant properties. Credit: Kota lab/Colorado State University

The Kota lab at Colorado State University has created a superomniphobic tape that adheres to any surface and imparts liquid-repellant properties. Credit: Kota lab/Colorado State University

An Oct. 20, 2016 news item on ScienceDaily celebrates the creation of a liquid-repelling superomniphobic tape,

Arun Kota, assistant professor of mechanical engineering at Colorado State University, has made a superomniphobic tape that, when adhered to any surface, gives the surface liquid-repelling properties. This recent breakthrough has been published by the American Chemical Society.

An Oct. 20, 2016 Colorado State University news release on EurekAlert, which originated the news item, provides more description,

Superomniphobic surfaces are extremely repellent to all liquids, made possible by an air cushion that lies between a liquid and a solid surface. With more than 10 years of research in this area, Kota has made many breakthroughs in super-repellent coatings. This latest product is similar in flexibility to Scotch Tape, but has the additional functionality of being extremely liquid-repellant.

Kota, doctoral student Hamed Vahabi, and postdoctoral fellow Wei Wang, developed the unusual tape. Though simple at first glance, the technology’s potential impact is extraordinary, the researchers say.

The concept of superomniphobic surfaces isn’t new. Researchers have been studying superomniphobic coatings since about 2007, and currently superomniphobic coatings can be sprayed, deposited or etched onto any surface for a similar effect; however, it requires costly equipment, complex techniques, and must be done by an experienced professional.

By contrast, the Kota group’s superomniphobic tape can be used by anyone, making it a practical solution in a variety of civilian, commercial, and military applications including corrosion resistance, self cleaning, drag reduction, liquid waste minimization, and more.

The researchers feel that future challenges in this field are exciting ­- yet puzzling. While many applications of superomniphobic coatings have already been outlined, coming up with a superomniphobic coating that is mechanically durable remains a major challenge.

Kota has filed a patent and sees tape and adhesive manufacturers as well as the packing industry having a strong interest in the product. He and his group will continue to research the mechanical durability of their product.

Here’s a link to and a citation for the paper,

Free-Standing, Flexible, Superomniphobic Films by Hamed Vahabi, Wei Wang, Sanli Movafaghi, and Arun K. Kota. ACS Appl. Mater. Interfaces, 2016, 8 (34), pp 21962–21967 DOI: 10.1021/acsami.6b06333 Publication Date (Web): August 19, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.

DARPA (US Defense Advanced Research Project Agency) ‘Atoms to Product’ program launched

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It took over a year after announcing the ‘Atoms to Product’ program in 2014 for DARPA (US Defense Advanced Research Projects Agency) to select 10 proponents for three projects. Before moving onto the latest announcement, here’s a description of the ‘Atoms to Product’ program from its Aug. 27, 2014 announcement on Nanowerk,

Many common materials exhibit different and potentially useful characteristics when fabricated at extremely small scales—that is, at dimensions near the size of atoms, or a few ten-billionths of a meter. These “atomic scale” or “nanoscale” properties include quantized electrical characteristics, glueless adhesion, rapid temperature changes, and tunable light absorption and scattering that, if available in human-scale products and systems, could offer potentially revolutionary defense and commercial capabilities. Two as-yet insurmountable technical challenges, however, stand in the way: Lack of knowledge of how to retain nanoscale properties in materials at larger scales, and lack of assembly capabilities for items between nanoscale and 100 microns—slightly wider than a human hair.

DARPA has created the Atoms to Product (A2P) program to help overcome these challenges. The program seeks to develop enhanced technologies for assembling atomic-scale pieces. It also seeks to integrate these components into materials and systems from nanoscale up to product scale in ways that preserve and exploit distinctive nanoscale properties.

DARPA’s Atoms to Product (A2P) program seeks to develop enhanced technologies for assembling nanoscale items, and integrating these components into materials and systems from nanoscale up to product scale in ways that preserve and exploit distinctive nanoscale properties.

A Dec. 29, 2015 news item on Nanowerk features the latest about the project,

DARPA recently selected 10 performers to tackle this challenge: Zyvex Labs, Richardson, Texas; SRI, Menlo Park, California; Boston University, Boston, Massachusetts; University of Notre Dame, South Bend, Indiana; HRL Laboratories, Malibu, California; PARC, Palo Alto, California; Embody, Norfolk, Virginia; Voxtel, Beaverton, Oregon; Harvard University, Cambridge, Massachusetts; and Draper Laboratory, Cambridge, Massachusetts.

A Dec. 29, 2015 DARPA news release, which originated the news item, offers more information and an image illustrating the type of advances already made by one of the successful proponents,

DARPA recently launched its Atoms to Product (A2P) program, with the goal of developing technologies and processes to assemble nanometer-scale pieces—whose dimensions are near the size of atoms—into systems, components, or materials that are at least millimeter-scale in size. At the heart of that goal was a frustrating reality: Many common materials, when fabricated at nanometer-scale, exhibit unique and attractive “atomic-scale” behaviors including quantized current-voltage behavior, dramatically lower melting points and significantly higher specific heats—but they tend to lose these potentially beneficial traits when they are manufactured at larger “product-scale” dimensions, typically on the order of a few centimeters, for integration into devices and systems.

…

“The ability to assemble atomic-scale pieces into practical components and products is the key to unlocking the full potential of micromachines,” said John Main, DARPA program manager. “The DARPA Atoms to Product Program aims to bring the benefits of microelectronic-style miniaturization to systems and products that combine mechanical, electrical, and chemical processes.”

The program calls for closing the assembly gap in two steps: From atoms to microns and from microns to millimeters. Performers are tasked with addressing one or both of these steps and have been assigned to one of three working groups, each with a distinct focus area.

…

A2P

Image caption: Microscopic tools such as this nanoscale “atom writer” can be used to fabricate minuscule light-manipulating structures on surfaces. DARPA has selected 10 performers for its Atoms to Product (A2P) program whose goal is to develop technologies and processes to assemble nanometer-scale pieces—whose dimensions are near the size of atoms—into systems, components, or materials that are at least millimeter-scale in size. (Image credit: Boston University)

Here’s more about the projects and the performers (proponents) from the A2P performers page on the DARPA website,

Nanometer to Millimeter in a Single System – Embody, Draper and Voxtel

Current methods to treat ligament injuries in warfighters [also known as, soldiers]—which account for a significant portion of reported injuries—often fail to restore pre-injury performance, due to surgical complexities and an inadequate supply of donor tissue. Embody is developing reinforced collagen nanofibers that mimic natural ligaments and replicate the biological and biomechanical properties of native tissue. Embody aims to create a new standard of care and restore pre-injury performance for warfighters and sports injury patients at a 50% reduction compared to current costs.

Radio Frequency (RF) systems (e.g., cell phones, GPS) have performance limits due to alternating current loss. In lower frequency power systems this is addressed by braiding the wires, but this is not currently possibly in cell phones due to an inability to manufacture sufficiently small braided wires. Draper is developing submicron wires that can be braided using DNA self-assembly methods. If successful, portable RF systems will be more power efficient and able to send 10 times more information in a given channel.

For seamless control of structures, physics and surface chemistry—from the atomic-level to the meter-level—Voxtel Inc. and partner Oregon State University are developing an efficient, high-rate, fluid-based manufacturing process designed to imitate nature’s ability to manufacture complex multimaterial products across scales. Historically, challenges relating to the cost of atomic-level control, production speed, and printing capability have been effectively insurmountable. This team’s new process will combine synthesis and delivery of materials into a massively parallel inkjet operation that draws from nature to achieve a DNA-like mediated assembly. The goal is to assemble complex, 3-D multimaterial mixed organic and inorganic products quickly and cost-effectively—directly from atoms.

Optical Metamaterial Assembly – Boston University, University of Notre Dame, HRL and PARC.

Nanoscale devices have demonstrated nearly unlimited power and functionality, but there hasn’t been a general- purpose, high-volume, low-cost method for building them. Boston University is developing an atomic calligraphy technique that can spray paint atoms with nanometer precision to build tunable optical metamaterials for the photonic battlefield. If successful, this capability could enhance the survivability of a wide range of military platforms, providing advanced camouflage and other optical illusions in the visual range much as stealth technology has enabled in the radar range.

The University of Notre Dame is developing massively parallel nanomanufacturing strategies to overcome the requirement today that most optical metamaterials must be fabricated in “one-off” operations. The Notre Dame project aims to design and build optical metamaterials that can be reconfigured to rapidly provide on-demand, customized optical capabilities. The aim is to use holographic traps to produce optical “tiles” that can be assembled into a myriad of functional forms and further customized by single-atom electrochemistry. Integrating these materials on surfaces and within devices could provide both warfighters and platforms with transformational survivability.

HRL Laboratories is working on a fast, scalable and material-agnostic process for improving infrared (IR) reflectivity of materials. Current IR-reflective materials have limited use, because reflectivity is highly dependent on the specific angle at which light hits the material. HRL is developing a technique for allowing tailorable infrared reflectivity across a variety of materials. If successful, the process will enable manufacturable materials with up to 98% IR reflectivity at all incident angles.

PARC is working on building the first digital MicroAssembly Printer, where the “inks” are micrometer-size particles and the “image” outputs are centimeter-scale and larger assemblies. The goal is to print smart materials with the throughput and cost of laser printers, but with the precision and functionality of nanotechnology. If successful, the printer would enable the short-run production of large, engineered, customized microstructures, such as metamaterials with unique responses for secure communications, surveillance and electronic warfare.

Flexible, General Purpose Assembly – Zyvex, SRI, and Harvard.

Zyvex aims to create nano-functional micron-scale devices using customizable and scalable manufacturing that is top-down and atomically precise. These high-performance electronic, optical, and nano-mechanical components would be assembled by SRI micro-robots into fully-functional devices and sub-systems such as ultra-sensitive sensors for threat detection, quantum communication devices, and atomic clocks the size of a grain of sand.

SRI’s Levitated Microfactories will seek to combine the precision of MEMS [micro-electromechanical systems] flexures with the versatility and range of pick-and-place robots and the scalability of swarms [an idea Michael Crichton used in his 2002 novel Prey to induce horror] to assemble and electrically connect micron and millimeter components to build stronger materials, faster electronics, and better sensors.

Many high-impact, minimally invasive surgical techniques are currently performed only by elite surgeons due to the lack of tactile feedback at such small scales relative to what is experienced during conventional surgical procedures. Harvard is developing a new manufacturing paradigm for millimeter-scale surgical tools using low-cost 2D layer-by-layer processes and assembly by folding, resulting in arbitrarily complex meso-scale 3D devices. The goal is for these novel tools to restore the necessary tactile feedback and thereby nurture a new degree of dexterity to perform otherwise demanding micro- and minimally invasive surgeries, and thus expand the availability of life-saving procedures.

Sidebar

‘Sidebar’ is my way of indicating these comments have little to do with the matter at hand but could be interesting factoids for you.

First, Zyvex Labs was last mentioned here in a Sept. 10, 2014 posting titled: OCSiAL will not be acquiring Zyvex. Notice that this  announcement was made shortly after DARPA’s A2P program was announced and that OCSiAL is one of RUSNANO’s (a Russian funding agency focused on nanotechnology) portfolio companies (see my Oct. 23, 2015 posting for more).

HRL Laboratories, mentioned here in an April 19, 2012 posting mostly concerned with memristors (nanoscale devices that mimic neural or synaptic plasticity), has its roots in Howard Hughes’s research laboratories as noted in the posting. In 2012, HRL was involved in another DARPA project, SyNAPSE.

Finally and minimally, PARC also known as, Xerox PARC, was made famous by Steven Jobs and Steve Wozniak when they set up their own company (Apple) basing their products on innovations that PARC had rejected. There are other versions of the story and one by Malcolm Gladwell for the New Yorker May 16, 2011 issue which presents a more complicated and, at times, contradictory version of that particular ‘origins’ story.

Transparent image sensor has no electronics or internal components

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This shows the world's first flexible and completely transparent image sensor. The plastic film is coated with fluorescent particles. Credit: Optics Express.

This shows the world’s first flexible and completely transparent image sensor. The plastic film is coated with fluorescent particles. Credit: Optics Express.

Stunning isn’t it? The work is from researchers at the Johannes Kepler University Linz in Austria and is featured in an article being published in Optics Express. From the Feb. 20, 2013 news release about the Optics Express article on EurekAlert,

Digital cameras, medical scanners, and other imaging technologies have advanced considerably during the past decade. Continuing this pace of innovation, an Austrian research team has developed an entirely new way of capturing images based on a flat, flexible, transparent, and potentially disposable polymer sheet. The team describes their new device and its possible applications in a paper published today in the Optical Society’s (OSA) open-access journal Optics Express.

The new imager, which resembles a flexible plastic film, uses fluorescent particles to capture incoming light and channel a portion of it to an array of sensors framing the sheet. With no electronics or internal components, the imager’s elegant design makes it ideal for a new breed of imaging technologies, including user interface devices that can respond not to a touch, but merely to a simple gesture.

The news release goes on to describe the technology,

The sensor is based on a polymer film known as a luminescent concentrator (LC), which is suffused with tiny fluorescent particles that absorb a very specific wavelength (blue light for example) and then reemit it at a longer wavelength (green light for example). Some of the reemitted fluorescent light is scattered out of the imager, but a portion of it travels throughout the interior of the film to the outer edges, where arrays of optical sensors (similar to 1-D pinhole cameras) capture the light. A computer then combines the signals to create a gray-scale image. “With fluorescence, a portion of the light that is reemitted actually stays inside the film,” says Bimber. [Oliver Bimber of the Johannes Kepler University Linz in Austria, co-author of the Optics Express paper] “This is the basic principle of our sensor.”

For the luminescent concentrator to work as an imager, Bimber and his colleagues had to determine precisely where light was falling across the entire surface of the film. This was the major technical challenge because the polymer sheet cannot be divided into individual pixels like the CCD camera inside a smartphone. Instead, fluorescent light from all points across its surface travels to all the edge sensors. Calculating where each bit of light entered the imager would be like determining where along a subway line a passenger got on after the train reached its final destination and all the passengers exited at once.

The solution came from the phenomenon of light attenuation, or dimming, as it travels through the polymer. The longer it travels, the dimmer it becomes. So by measuring the relative brightness of light reaching the sensor array, it was possible to calculate where the light entered the film. This same principle has already been employed in an input device that tracks the location of a single laser point on a screen.

The researchers were able to scale up this basic principle by measuring how much light arrives from every direction at each position on the image sensor at the film’s edge. They could then reconstruct the image by using a technique similar to X-ray computed tomography, more commonly known as a CT scan.

“In CT technology, it’s impossible to reconstruct an image from a single measurement of X-ray attenuation along one scanning direction alone,” says Bimber. “With a multiple of these measurements taken at different positions and directions, however, this becomes possible. Our system works in the same way, but where CT uses X-rays, our technique uses visible light.”

Currently, the resolution from this image sensor is low (32×32 pixels with the first prototypes). The main reason for this is the limited signal-to-noise ratio of the low-cost photodiodes being used. The researchers are planning better prototypes that cool the photodiodes to achieve a higher signal-to-noise ratio.

By applying advanced sampling techniques, the researchers can already enhance the resolution by reconstructing multiple images at different positions on the film. These positions differ by less than a single pixel (as determined by the final image, not the polymer itself). By having multiple of these slightly different images reconstructed, it’s possible to create a higher resolution image. “This does not require better photodiodes,” notes Bimber, “and does not make the sensor significantly slower. The more images we combine, the higher the final resolution is, up to a certain limit.”

The researchers discuss applications,

The main application the researchers envision for this new technology is in touch-free, transparent user interfaces that could seamlessly overlay a television or other display technology. This would give computer operators or video-game players full gesture control without the need for cameras or other external motion-tracking devices. The polymer sheet could also be wrapped around objects to provide them with sensor capabilities. Since the material is transparent, it’s also possible to use multiple layers that each fluoresce at different wavelengths to capture color images.

The researchers also are considering attaching their new sensor in front of a regular, high-resolution CCD sensor. This would allow recording of two images at the same time at two different exposures. “Combining both would give us a high-resolution image with less overexposed or underexposed regions if scenes with a high dynamic range or contrast are captured,” Bimber speculates. He also notes that the polymer sheet portion of the device is relatively inexpensive and therefore disposable. “I think there are many applications for this sensor that we are not yet aware of,” he concludes.

Here’s a citation and a link,

“Towards a transparent, flexible, scalable and disposable image sensor using thin-film luminescent concentrators,” A. Koppelhuber and O. Bimber, Optics Express, Vol. 21, Issue 4, pp. 4796-4810 (2013) (link: http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-21-4-4796).