Multidimensional Characterization Of Piezoresistive Carbon Black Silicone Rubber Composites

Flexible and stretchable electronic skins capable of replicating the human sense of touch are a subject of active research. One of the most popular materials for force sensors in skins is carbon black (CB)/polydimethylsiloxane composite. To aid in skin design, a characterization of this composite is presented here. The sensitivity of composite resistance to uniaxial tension, compression, and shear for each CB concentration is measured and found to be similar for tension and compression, but smaller for shear, with resistance monotonically increasing with strain. In addition, under tension and compression the resistance of the material is measured both in line with and perpendicular to the axis of applied strain, and the response is found to be approximately equal in both cases. The electrical and mechanical relaxation time of the material is also measured and modeled for tension, compression, and shear. The mechanical relaxation time is found to be shorter than the electrical, with both increasing with CB concentration. However, the shortest mechanical relaxation time, 200 s, precludes a sensor with human-like response times without an active modeling and compensation system. Finally, Young's modulus and Poisson's ratio are measured and reported for each CB concentration. (C) 2017 Wiley Periodicals, Inc.