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.
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.
Ming Xu, senior research associate at Case Western Reserve, hangs from two wooden blocks held to a painted wall with six small pieces of the double-sided adhesive.
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,”said Ajit Roy, of the Materials and Manufacturing Directorate, Air Force Research Laboratory.
“This adhesive can thus be used as connecting materials to enhance the performance of electronics at high temperatures,” Dai comments. “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.”