|A Surprising Development
For years Ramanath has investigated ways of assembling layers of molecular chains between two different materials to enhance the structural integrity, efficiency, and reliability of semiconductor devices in computer chips.
His team has shown that molecular chains with a carbon backbone ending with appropriate elements such as silicon, oxygen, or sulfur can improve adhesion and prevent heat-triggered mixing of atoms of the adjoining substances.
Recently, Ramanath’s group and other researchers have found these nanolayers to be useful for creating adhesives, lubricants, and protective surface coatings.
The nanolayers, however, are extremely susceptible to heat and begin to degrade or simply detach from a surface when exposed to temperatures above 400 degrees Celsius. This severe limitation has precluded more widespread use of the nanolayers.
Ramanath’s team decided to sandwich a nanolayer between a thin film of copper and silica, thinking the extra support would help strengthen the nanolayer’s bonds and boost its adhesive properties.
It proved to be an insightful venture, and the research team found more than it bargained for.
When exposed to heat, the middle layer of the “nanosandwich” did not break down or fall off as it had nowhere to go. But that was not the only good news.
The nanolayer’s bonds grew stronger and more adhesive when exposed to temperatures above 400 degrees Celsius. Constrained between the copper and silica, the nanolayer’s molecules hooked onto an adjoining surface with unexpectedly strong chemical bonds.