Julie Kalista
Online Editor
The adhesive is based on self-assembling, nonscale chains less than a nanometer thick. It is inexpensive to make and, it's molecular bond actually strengthens when exposed to heat.
For years, scientists have investigated ways of assembling layers of molcular chains between two materials to strengthen structures, making the nanolayers useful for creating adhesives, lubricants, and protective coatings. Nanolayers are, however, extremely susceptible to heat and degrade or detach from surfaces when exposed to temperatures above 400°C.
To combat this problem, researchers at Rensselaer Polytechnic Institute added a nanolayer between thin films of copper and silica. Not only does the middle layer stay strong and attached, but it actually grew stronger and more adhesive when exposed to temperatures above 400°C.
To confirm the results, the team recreated the test more than 50 times over the past two years. The tests have been consistent and show heat increases the nanolayer's stickiness by five to seven times. In fact, the nanolayer sandwiches continue to strengthen as temperatures climb to 700°C.
These results could lead to new methods of putting paint on hot surfaces, like on the inside of jet engines or power plant turbines. The researchers also envision the nanoglue to make computer chips and for energy production. The molecular glue is inexpensive, 100-g costs about $35 and is already commercially available.
More Information:Rensselaer Polytechnic Institute
Unprotected, a nanolayer (green ball: silicon, blue: sulphur, red: carbon, white: hydrogen) would degrade or detach from a surface when heated to 400°C. But when topped with a thin copper film that binds with the nanolayer, heat causes the nanolayer to form strong chemical bonds to the silica underlayer thus gluing the copper-silica sandwich together. This technique produces a sevenfold increase of the thin-film adhesion and lets nanolayers withstand temperatures up to 700°C.
