Microelectromechanical strain and pressure sensors based on electric field aligned carbon cone and carbon black particles in a silicone elastomer matrix

作者：Hoyer H^*; Knaapila M; Kjelstrup Hansen J; Helgesen G

来源：Journal of Applied Physics, 2012, 112(9): 094324.

DOI：10.1063/1.4759447

Methods for developing microelectromechanical strain and pressure sensors based on aligned carbon particle strings within dielectric elastomer matrices are presented. Two different types of carbon particles were used: a mixture of carbon cone and carbon disk particles and spherical carbon black particles. The particles were assembled and aligned into strings by an alternating electric field with a strength of 4 kV/cm and a frequency of 1 kHz, utilizing the dielectrophoretic effect. The particle fraction was about 0.1 vol. %, which is an order of magnitude lower than their percolation threshold (similar to 2 vol. %). The aligned strings were produced in a couple of minutes. The matrices were subsequently cured thus stabilizing the strings. Micromechanical strain sensors with a capacitive readout were produced by aligning the particles into a single string-like formation in the in-plane direction, the string dimensions being 3 mu m width and 30 mu m length. The pressure sensors with piezoresistive readout were made by aligning the particles into multiple unidirectional strings in the out-of-plane direction, the thickness of the sensors being of the order of 100 mu m and the lateral area of 1.5 cm(2). The strain and the pressure sensors show reversible piezocapacitive and piezoresistance effects when stretched and compressed, respectively.

• 出版日期2012-11-1