A prototype high sensitivity load cell using single walled carbon nanotube strain gauges

This paper presents a novel strain gauge made of single walled carbon nanotube (SWCNT) film and further discusses the usability of load cells with these gauges as sensors for force and weighing measurements. Key issues involve the deposition of the SWCNT films with strong adhesion to the backing materials, the integration of SWCNT films into existing micro technologies for batch-fabrication, and the bonding of the strain sensors to a binocular spring element. The batch-fabricated SWCNT strain gauges showed the linear relationship between resistance changes and externally applied strain. The sensitivity of the SWCNT gauges was measured to be approximately 30 times higher than that of commercial foil-type gauges. The effectiveness of a microfabricated SWCNT gauge as a force sensor was evaluated by applying it to high sensitivity binocular load cells. Our test results exhibited that SWCNT gauge load cells had much better resolution and higher sensitivity than the conventional metal foil-type cells. (C) 2012 Elsevier B.V. All rights reserved.