Gold connectors stretch

Researchers from Princeton University have found a way to make wrinkles useful.

The researchers have developed a type of conductor that is stretchable. The flexible conductor promises better connections for devices that attach to flexible surfaces like skin or that span oddly shaped spaces.

The conductor is a sandwich of a type of plastic, a 5-nanometer-thick layer of chromium, and 25- to 100-nanometer layer of gold. A nanometer is the span of ten hydrogen atoms.

The process of depositing the gold caused the layer to form a pattern of wrinkles that smooth out when the conductor is stretched. The film continues to conduct electricity when stretched as much as 22 percent, according to the researchers. Plain gold strips crack when they are stretched one or two percent.

The wrinkles can be patterned depending on what the conductors will be used for, according to the researchers.

The conductors could improve retina-shaped photosensor arrays, plastic actuators, and stretchable sensitive skin for machines, according to the researchers.

The conductors could be ready for use in practical devices in five to ten years, according to the researchers. The work appeared in the the April, 2003 issue of Applied Physics Letters.