The elastic microstructures of inkjet printed polydimethylsiloxane as the patterned dielectric layer for pressure sensors

A direct inkjet printing process was developed to fabricate patterned elastic microstructures for pressure sensors using n-butyl acetate diluted polymethylsiloxane (PDMS). The diluted PDMS precursor mixture with a cross-linker exhibited a controllable viscosity below 14 cP in 48 h at 25 degrees C, and the PDMS film had lower elastic modulus and hardness values than the non-diluted PDMS precursor after curing. The capacitor using the printed PDMS film as the microstructured dielectric layer showed a very high pressure sensitivity of up to 10.4 kPa(-1) under the pressure below 70 Pa, and the pressure sensitivity would be dramatically decreased to 0.043-0.052 kPa(-1) under the pressure between 2 and 8 kPa. Furthermore, the triboelectric sensors could be structured with an inkjet printed PDMS film and controllably generate the voltage signals up to 1.23V without any amplification. The results suggest that mechanical properties and patterned elastic microstructures play the key roles in PDMS-based sensor devices, and the PDMS dielectric layer with controlled mechanical properties and microstructures fabricated via directly inkjet printing opens up the applications of the PDMS and its composites in functional devices. Published by AIP Publishing.