U.S. scientists say they are seeking a way of controlling the Casimir force -- a quantum mechanical force that hampers creation of nanoscale machines.

Researchers at the Department of Energy's Argonne National Laboratory said the Casimir force, which attracts objects when they are only 100 nanometers apart, is so small most experimentation has only dealt with its characteristics.

"If we can control this force or make it repulsive, it can have dramatic effects on the development of nanoelectromechanical systems," said Derrick Mancini, interim director of the Argonne Center for Nanoscale Materials.

The researchers said nanoelectromechanical systems, usually referred to as NEMS, are nanometer size mechanical devices that can be used for actuation or sensing at the nanoscale.

In the macro world, the Casimir force is so small it can be barely detected, the scientists said. But at the nanoscale it becomes a quantum effect that scientists cannot currently control.

"As characteristic device dimensions shrink to the nanoscale, the effects of the attractive Casimir force becomes more pronounced, making very difficult to control nanodevices," said Argonne scientist Daniel Lopez. "This is a technological challenge that (needs) to be addressed before the full potential of NEMS devices can be demonstrated."

Officials said the project will include researchers from Argonne, Indiana University, Purdue University, the National Institute of Standards and Technology and the Los Alamos National Laboratory.