Flexible pressure sensor with a “V-type” array microelectrode on a grating PDMS substrate

Purpose This paper aims to provide a fabrication and measurement of a highly stretchable pressure sensor with a “V-type” array microelectrode on a grating PDMS substrate. Design/methodology/approach First, the “V-type” array structure on the silicon wafer was fabricated by the MEMS technology, and the fabrication process included ultra-violet lithography and silicon etching. The “V-type” array structure on the master mold was then replicated into polycarbonate, which served as an intermediate, negative mold, using a conventional nanoimprint lithography technique. The negative mold was subsequently used in the PDMS molding process to produce PDMS “V-type” array structures with the same structures as the master mold. An Ag film was coated on the PDMS “V-type” array structure surface by the magnetron sputtering process to obtain PDMS “V-type” array microelectrodes. Finally, a PDMS prepolymer was prepared using a Sylgard184 curing agent with a weight ratio of a 20:1 and applied to the cavity at the middle of the two-layer PDMS “V-type” array microelectrode template to complete hot-press bonding, and a pressure sensor was realized. Findings The experimental results showed that the PDMS “V-type” array microelectrode has high stretchability of 65 per cent, temperature stability of 0.0248, humidity stability of 0.000204, bending stability and cycle stability. Capacitive pressure sensors with a “V-type” array microelectrode exhibit ideal initial capacitance (111.45 pF), good pressure sensitivity of 0.1143 MPa-1 (0-0.35 Mpa), fast response and relaxation times (<200 ms), high bending stability, high temperature/humidity stability and high cycle stability. Originality/value The PDMS “V-type” array structure microelectrode can be used to fabricate pressure sensors and is highly flexible, crack-free and durable.

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