Ordinarily, if you want to separate two objects that are glued together, harsh solvents or mechanical force are required – either one could damage the items. A new glue, however, releases its bond by simply turning to gas.
Developed by scientists at New Hampshire's Dartmouth College, the experimental adhesive is composed of what are known as molecular solids. These are described as being like "individual chemical beads that sit atop each other." By contrast, most glues are made of polymers, which are more like long intertwined chemical chains.
And whereas polymer adhesives have to be chemically dissolved or wrenched apart in order to break their bond, the molecular solids glue gets heated in a vacuum environment. In a process called sublimation, this causes it to change directly from a solid crystalline form to a gaseous form, bypassing the liquid phase. The previously bonded objects can then be easily separated, without any risk of damage.
While the glue is claimed to have a bonding strength similar to that of polymer adhesives, it isn't likely to become a consumer product anytime soon. That said, the researchers hope that it could find use in fields such as electronics manufacturing.
"This temporary adhesive works in an entirely different way than other adhesives," says Asst. Prof. Katherine Mirica. "This innovation will unlock new manufacturing strategies where on-demand release from adhesion is required."
A paper on the research was recently published in the journal Chemistry of Materials.
Source: Dartmouth College
