Researchers from Case Western Reserve University, Dayton Air Force Research Laboratory and China have developed a new dry adhesive that bonds in extreme temperatures—a quality that could make the product ideal for space exploration and beyond.
The gecko-inspired adhesive loses no traction in temperatures as cold as liquid nitrogen or as hot as molten silver, and actually gets stickier as heat increases, the researchers report.
The research, which builds on earlier development of a single-sided dry adhesive tape based on vertically aligned carbon nanotubes, is published in the journal Nature Communications. As far as the researchers know, no other dry adhesive is capable of working at such temperature extremes.
Liming Dai, professor of macromolecular science and engineering at Case Western Reserve and an author of the study teamed with Ming Xu, a senior research associate at Case School of Engineering and visiting scholar from Huazhong University of Science and Technology; Feng Du, senior research associate in Case Western Reserve’s Department of Macromolecular Science and Engineering; and Sabyasachi Ganguli and Ajit Roy, of the Materials and Manufacturing Directorate, Air Force Research Laboratory.
Vertically aligned carbon nanotubes with tops bundled into nodes replicate the microscopic hairs on the foot of the wall-walking reptile and remain stable from -320 degrees Fahrenheit to 1,832 degrees, the scientists say.
“When you have aligned nanotubes with bundled tops penetrating into the cavities of the surface, you generate sufficient van der Waal’s forces to hold,” Xu said. “The dry adhesive doesn’t lose adhesion as it cools because the surface doesn’t change. But when you heat the surface, the surface becomes rougher, physically locking the nanotubes in place, leading to stronger adhesion as temperatures increase.”
Because the adhesive remains useful over such a wide range of temperatures, the inventors say it is ideally suited for use in space, where the shade can be frigid and exposure to the sun blazing hot.
In addition to range, the bonding agent offers properties that could add to its utility. The adhesive conducts heat and electricity, and these properties also increase with temperature. “When applied as a double-sided sticky tape, the adhesive can be used to link electrical components together and also for electrical and thermal management,” Roy said.
“This adhesive can thus be used as connecting materials to enhance the performance of electronics at high temperatures,” Dai said. “At room temperature, the double-sided carbon nanotube tape held as strongly as commercial tape on various rough surfaces, including paper, wood, plastic films and painted walls, showing potential use as conducting adhesives in home appliances and wall-climbing robots.”
In testing, a double-sided tape made with the carbon nanotubes (CNTs) applied between two layers of copper foil had an adhesive strength of about 37 newtons per cm-2 at room temperature, about the same as a commercial double-sided sticky tape.
Unlike the commercial tape, which loses adhesion as it freezes or is heated, the CNT adhesive maintained its strength down to -320 degrees Fahrenheit. The adhesive strength more than doubled at 785 degrees Fahrenheit and was about six times as strong at 1891 degrees.
Surprised by the increasing adhesive strength, the researchers used a scanning electron microscope to search for the cause. They found that, as the bundled nodes penetrate the surface cavities, the flexible nanotubes no longer remain vertically aligned but collapse into web-like structures. The action appears to enhance the van der Waal’s forces due to an increased contact surface area with the collapsed nanotubes.
Looking further, the researchers found that as the temperature increased above 392 degrees Fahrenheit, the surface of the copper foil became increasingly rough. The bundled ends and collapsed nanotubes appear to penetrate deeper into the heat-induced irregularities in the surface, increasing adhesion. The researchers dub this adhesion mechanism “nano-interlocking.”
The adhesive held strong during hundreds of temperature transition cycles between ambient temperature and -320 degrees then up to 1891 degrees and between the cold extreme and ambient temperature.
Copper foil, which was used for many of the tests to demonstrate the potential for thermal management, is not unique. The surface of many other materials, including polymer films and other metal foils, roughen when heat is applied, making them good targets for this kind of adhesive, the team suggests.
Swarms could one day search the depths of fresh and saltwater
Researchers at Case Western Reserve University have combined tissues from a sea slug with flexible 3-D printed components to build “biohybrid” robots that crawl like sea turtles on the beach.
A muscle from the slug’s mouth provides the movement, which is currently controlled by an external electrical field. However, future iterations of the device will include ganglia, bundles of neurons and nerves that normally conduct signals to the muscle as the slug feeds, as an organic controller.
The researchers also manipulated collagen from the slug’s skin to build an organic scaffold to be tested in new versions of the robot.
In the future, swarms of biohybrid robots could be released for such tasks as locating the source of a toxic leak in a pond that would send animals fleeing, the scientists say. Or they could search the ocean floor for a black box flight data recorder, a potentially long process that may leave current robots stilled with dead batteries.
“We’re building a living machine—a biohybrid robot that’s not completely organic—yet,” said Victoria Webster, a PhD student who is leading the research. Webster will discuss mining the sea slug for materials and constructing the hybrid, which is a little under 2 inches long, at the Living Machines conference in Edinburgh, Scotland, this week.
Case Western Reserve University (also known as Case Western Reserve, Case Western, Case, Reserve, and CWRU) is a private research university in Cleveland, Ohio, USA.
The university was created in 1967 by the federation of Case Institute of Technology (founded in 1881 by Leonard Case Jr.) and Western Reserve University (founded in 1826 in the area that was once the Connecticut Western Reserve). TIME magazine described the merger as the creation of “Cleveland’s Big-Leaguer” university.
In U.S. News & World Report’s 2013 rankings, Case Western Reserve’s undergraduate program ranked 37th among national universities. The University is associated with 16 Nobel Laureates. Other notable alumni include Paul Buchheit, creator and lead developer of Gmail; Craig Newmark, founder of craigslist.org; and Peter Tippett, who developed the anti-virus software, Vaccine, which Symantec purchased and turned into the popular Norton AntiVirus. Case Western Reserve is particularly well known for its medical school, dental school, law school, Frances Payne Bolton School of Nursing, Department of Biomedical Engineering and its biomedical teaching and research capabilities. Case Western is a member of the Association of American Universities.
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Case Western Reserve University research articles from Innovation Toronto
- Researchers Build a Crawling Robot From Sea Slug Parts and a 3-D Printed Body – July 23, 2016
- Researchers block common colon cancer tumor type in mice – clinical trial starts in August – July 21, 2016
- Simple shell of plant virus sparks immune response against cancer – December 23, 2015
- CWRU researchers tailor flexible microsupercapacitors for wearable electronics – December 17, 2015
- New nanomaterial maintains conductivity in three dimensions – September 5, 2015
- CWRU researchers efficiently charge a lithium-ion battery with solar cell — August 28, 2015
- New drug triggers tissue regeneration: Faster regrowth and healing of damaged tissues – June 15, 2015
- Another Good Step Forward for Clean Energy – February 28, 2015
- Barrier breaking drug may lead to spinal cord injury treatments – December 11, 2014
- Flexible supercapacitor could have big advantages over batteries for wearable devices – May 12, 2014
- In Case You Wondered, a Real Human Wrote This Column
- Engineering Researchers Report On Nanoscale Energy-Efficient Switching Devices
- Neural prosthesis restores behavior after brain injury
- Vivax malaria may be evolving around natural defense
- CWRU makes nanodiamonds at atmospheric pressure and near room temperature
- Feds fund concept for cheaper, better titanium made in U.S.
- CWRU philosopher examines the hypothesis vs. exploratory funding divide
- First-Ever Therapeutic Offers Hope for Improving Blood Transfusions
- Metal-free catalyst outperforms platinum in fuel cell
- New Nerve and Muscle Interfaces Aid Wounded Warrior Amputees
- Vitamin E Identified as Potential Weapon Against Obesity
- Ordinary Skin Cells Morphed into Functional Brain Cells
- New MRI Technology Diagnoses in Seconds Rather than Hours
- New MRI method fingerprints tissues and diseases
- Breakthrough in Doubling the Survival Rate of Internal Injuries
- Machine Counterpart: Nature’s New Creatures
- Alzheimer’s Breakthrough – Part 2
- Patients Clamor for Cancer Drug That Shows Promise for Alzheimer’s in Mice
- Drug Quickly Reverses Alzheimer’s Symptoms in Mice
- Powering insect cyborgs with an implantable biofuel cell
- Carbon nanotube-reinforced polyurethane could make for bigger and better wind turbines
- New Way to Treat Common Hospital-Acquired Infection
- Artificial Lung Mimics Real Organ’s Design and Efficiency
- Heal thyself: Rubbery polymer self-repairs under light exposure
- Funding to boost development of high-energy density capacitors for hybrids and EVs
- An old idea may help solve the problem of plastic waste
- Intergalactic Controversy
- Telescope to track space junk using youth radio station
- Hashtag Health
- Scientists identify the world’s most irreplaceable protected areas
- Cleaner Than Coal? Wood Power Makes a Comeback
- Beyond antibiotics: “PPMOs” offer new approach to bacterial infection
- New Treatment for “Arthritis of the Spine” Prevents Paralysis
- 4.4 million jobs will be created worldwide to support Big Data by 2015
- Oxygen – key to most life – decelerates many cancer tumors when combined with radiation therapy
- Desktop Printing at the Nano Level
- Researchers describe potential for MERS coronavirus to spread internationally after mass gatherings in the Middle East this summer and fall
- Cyborgs, a fusion of man and machine
- Keeping Networks Under Control
- China’s Twitter Revolution is Slow in Coming
- Efforts to Resuscitate Extinct Species May Spawn a New Era of the Hybrid
- Early warning system provides four-month forecast of malaria epidemics in northwest India
- Breakthrough nanoparticle halts multiple sclerosis
- As Dengue Fever Sweeps India, a Slow Response Stirs Experts’ Fears
- Artificial Intelligence Used to Home In on New Fossil Sites
- Study offers new hope for increasing global food production, reducing environmental impact of agriculture
- Breast Cancer
- The Moral Hazard of Drones
- Local grid energy storage set to complement solar feed-ins
- How to Stop Wildlife Poachers
- Emergence of Artemisinin Resistance On Thai-Myanmar Border Raises Spectre of Untreatable Malaria
- Small modular nuclear reactors – the future of energy?
- Do Drones Undermine Democracy?
- More Companies Bypassing Electric Grid Inefficiencies With Fuel Cells
- New method may lead to improved detection of nuclear materials
- Deep Thinking About the Future of Food
- Restoring Blood Flow After a Heart Attack
- Chilling foam and gel in spray-cans cool down Japan this summer
- Envion Oil Generator turns plastic waste into oil
- The Great Green Wall: African Farmers Beat Back Drought and Climate Change with Trees
- Japan Goes From Dynamic to Disheartened
- Is the Flooding in Pakistan a Climate Change Disaster?
- Haier Power Pad takes energy from shower water and returns it to hot water system
- Doomsayers Beware, a Bright Future Beckons
- Elusive Goal of Greening U.S. Energy
Findings lay groundwork for human clinical trial planned for August 2016
A new scientific study has identified why colorectal cancer cells depend on a specific nutrient, and a way to starve them of it. Over one million men and women are living with colorectal cancer in the United States. The National Cancer Institute estimates 4.5% of all men and women will be diagnosed with the cancer during their lifetime, making it the third most common non-skin cancer.
In the study published online in Nature Communications, researchers showed how certain colorectal cancer cells reprogram their metabolism using glutamine, a non-essential amino acid. Many cancer cells rely on glutamine to survive. How they become so dependent on the molecule is hotly debated in the field.
Researchers studied a subset of colorectal cancer cells containing a genetic mutation called PIK3CA. This mutation is located in a gene critical for cell division and movement, and is found in approximately one third of all colorectal cancers. The mutation is also the most commonly identified genetic mutation across all cancers, making the results of the study universally appealing.
An international team of scientists has developed what may be the first one-step process for making seamless carbon-based nanomaterials that possess superior thermal, electrical and mechanical properties in three dimensions.
The research holds potential for increased energy storage in high efficiency batteries and supercapacitors, increasing the efficiency of energy conversion in solar cells, for lightweight thermal coatings and more. The study is published today (Sept. 4) in the online journal Science Advances.
In early testing, a three-dimensional (3D) fiber-like supercapacitor made with the uninterrupted fibers of carbon nanotubes and graphene matched or bettered–by a factor of four–the reported record-high capacities for this type of device.
Used as a counter electrode in a dye-sensitized solar cell, the material enabled the cell to convert power with up to 6.8 percent efficiency and more than doubled the performance of an identical cell that instead used an expensive platinum wire counter electrode.
Scientists from Case Western Reserve University and University of Kansas Medical Center have restored behavior—in this case, the ability to reach through a narrow opening and grasp food—using a neural prosthesis in a rat model of brain injury.
Ultimately, the team hopes to develop a device that rapidly and substantially improves function after brain injury in humans. There is no such commercial treatment for the 1.5 million Americans, including soldiers in Afghanistan and Iraq, who suffer traumatic brain injuries (TBI), or the nearly 800,000 stroke victims who suffer weakness or paralysis in the United States, annually.
The prosthesis, called a brain-machine-brain interface, is a closed-loop microelectronic system. It records signals from one part of the brain, processes them in real time, and then bridges the injury by stimulating a second part of the brain that had lost connectivity.
“If you use the device to couple activity from one part of the brain to another, is it possible to induce recovery from TBI? That’s the core of this investigation,” said Pedram Mohseni, professor of electrical engineering and computer science at Case Western Reserve, who built the brain prosthesis.
“We found that, yes, it is possible to use a closed-loop neural prosthesis to facilitate repair of a brain injury,” he said.
The researchers tested the prosthesis in a rat model of brain injury in the laboratory of Randolph J. Nudo, professor of molecular and integrative physiology at the University of Kansas. Nudo mapped the rat’s brain and developed the model in which anterior and posterior parts of the brain that control the rat’s forelimbs are disconnected.
Atop each animal’s head, the brain-machine-brain interface is a microchip on a circuit board smaller than a quarter connected to microelectrodes implanted in the two brain regions.
The device amplifies signals, which are called neural action potentials and produced by the neurons in the anterior of the brain. An algorithm separates these signals, recorded as brain spike activity, from noise and other artifacts. With each spike detected, the microchip sends a pulse of electric current to stimulate neurons in the posterior part of the brain, artificially connecting the two brain regions.
Two weeks after the prosthesis had been implanted and run continuously, the rat models using the full closed-loop system had recovered nearly all function lost due to injury, successfully retrieving a food pellet close to 70 percent of the time, or as well as normal, uninjured rats. Rat models that received random stimuli from the device retrieved less than half the pellets and those that received no stimuli retrieved about a quarter of them.
“A question still to be answered is must the implant be left in place for life?” Mohseni said. “Or can it be removed after two months or six months, if and when new connections have been formed in the brain?”
What if mending a ripped garment, or repairing a leaky storage container, was as easy as shining a light on the damage?
We’re not there yet, but such materials could be possible in the future—researchers have now demonstrated a new way to produce light-healed polymers. In the April 21 issue of Nature, a group from Case Western Reserve University, the U.S. Army Research Laboratory and the University of Fribourg in Switzerland reported the creation of polymers that heal their own wounds under brief exposures to ultraviolet light. (Scientific American is part of Nature Publishing Group.)
Many materials can self-repair with the help of heat, which liquefies the material and allows it to fill cuts, cracks, or gaps. The light-healed polymers work in much the same way: ultraviolet light excites the material, causing it to heat up and temporarily liquefy. When the light source is switched off, the polymer cools and resolidifies, having filled its cracks and gashes.
“We’ve shown that cuts or scratches in such materials can be healed by exposure to lamps—simple lamps such as those dentists use, for example, to cure fillings,” study co-author Christoph Weder of the University of Fribourg said in an April 19 teleconference. Some of Weder’s group’s experimental materials, which include metal ions such as zinc or lanthanum in a rubbery polymer, were able to regain their original toughness after light-induced repairs.
The polymers are composed of small building blocks assembled “to basically mimic the molecular architecture of normal polymers,” Weder explained. “We have small building blocks with sticky end groups, and those sticky end groups are kind of glued together. We heal these materials by exposure to light, and what light does is it unglues these sticky end groups and liquefies the material.”
The healing process is relatively quick—two exposures of 30 seconds each did the trick for one experimental polymer, which quickly heated up to 220 degrees Celsius and liquefied. A 2009 study from another group reported a similar self-repair effect for polyurethanes, but that effect required much longer UV exposures. Weder said the researchers were now investigating how to get the same results from other wavelengths of light—for instance, a polymer that repairs itself under illumination by blue visible light.