An Inner-Structure-Based Differential Piezoresistive Device Made of Conductive Polymer Composite

To increase the absolute value of the sensitivity of flexible piezoresistive sensor based on conductive polymer composite under low compressive pressure, an inner-structure-based piezoresistive device is designed. The differential properties of the two subsensing elements in the device are realized by the different inner structures caused by the different conductive phase contents of the composites. The conductive phase content of the composite in the first subsensing element is lower than the critical conductive phase content, and the electrical resistance of it increases with the increase in compressive pressure. The conductive phase content of the composite in the second subsensing element is higher than the critical conductive phase content, and the electrical resistance of it decreases with the increase in compressive pressure. Using the two subsensing elements as the neighboring arms of an electrical bridge, the conversion from the compressive pressure to the voltage is realized. The results indicate that the absolute value of the sensitivity can be improved using the inner-structure-based piezoresistive device made of conductive polymer composite.