Ultra-sensitive wide-range small capacitive pressure sensor based on porous CCTO-PDMS membrane

Abstract

Dielectric elastomer is a very popular composite material used for different applications. Calcium copper titanate (CCTO) particles have a high dielectric constant, while polydimethylsiloxane (PDMS) is a commonly used flexible elastomer with good elastic property and durable chemical resistance, and their composite has shown an important and unique character for the fabrication of the pressure/force sensor. To improve the sensitivity of the capacitive sensor, various elastomers’ microstructures have been introduced; but the methods used to manufacture microstructures in PDMS have so far been more difficult, requiring special equipment or hazardous chemicals such as strong acids and alkalis, otherwise, the sponge-like structures produced are slightly larger and cannot be applied to very small scenes. In this report, the extraction method was used to manufacture porous microstructures of the PDMS with multiple porosities; the influence of different porosities and pore sizes on the sensitivity of capacitive pressure sensors, which can increase the sensitivity of capacitive pressure sensors, the measuring force range, and also applied to tiny scenes, were explored. Additionally, the current methodology for manufacturing porous PDMS composite membranes is also suitable for the manufacture of other thinner PDMS composite porous membranes.