A highly elastic strain sensing unit, consisting of a single modified carbon nanocoil (CNC) as the substrate, a layer of titanium film as the sensing layer and an Al2O3 film as the insulation layer between them, has been fabricated and studied. This unit has the ability of transforming a large macro longitudinal stretching to a small local torsional strain. According to the changes of resistance with the strain, it is found that the resistance variation of the unique three-dimensional helical composite structure is as high as 30% in the deformation of micrometer scale, and the ratio of resistance change to overall strain of the composite and the average strain of Ti particles reach 5 and 100, respectively. It provides a theoretical and experimental foundation for the applications of the strain sensing to the micro-electromechanical systems or microsensing systems.
