Novel flexible force sensor based on carbon composites

A novel route was developed to fabricate a new flexible force sensor which can be used on regular and unregular surfaces to disperse homogeneously conductive carbon particles in an insulating silicone rubber matrix. The butanone solution was used to finish this process on the polyimide substrate. The diaphragm of traditional MEMS force sensor was replaced by butakon rubber of 500 um on thickness, which converts the touch force into transverse stress. In piezoresistivity experiment, the flexible sensor shows a gradual change in electrical resistivity with applied force within percolation threshold region at a constant temperature. Experiments also show that the sensor has excellent temperature stability and time stability. A quantitative general effective media (GEM) theory was used to understand the resistivity of carbon composites system over a repeatable change of conductive paths of carbon with applied pressure.