A novel liquid metal sensor with three microchannels embedded in elastomer

Abstract

In this paper, a new type of liquid metal sensor structure is designed and fabricated, in which three microchannels, including one upper channel and two lower channels, are symmetrically arranged in PDMS (polydimethylsiloxane) elastomer. With this structure, pressure can be sensed by detecting resistance, and strain and curvature can also be sensed by detecting capacitance and resistance. The cross-sectional deformational of microchannel 1 in the pressure sensor and the corresponding resistance variation are deduced. The initial capacitance of the strain sensor is increased through the series–parallel connection of three microchannels, which effectively enlarges the capacitance variation per unit strain. Regression analysis of the experimental data is performed, and the univariate nonlinear regression can be simplified to a multivariate linear regression. Moreover, tests on the different commonly employed temperature (0 °C–20 °C) are conducted, it is found from the experimental results that the effect of commonly employed temperature on sensors can be neglected. The experimental data from the pressure sensor are in good agreement with the theoretical curve, especially in the range of 0–4 MPa. Within the measurable strain range (0%–30%), the experimental values of the strain sensors are in good agreement with the theoretical values. In addition, the analytical theory is developed to explain the performance of the sensor, although it can not explain all the observed data well.