A novel pressure sensor with a PDMS diaphragm

This paper describes a novel pressure sensor with a polydimethylsiloxane (PDMS) diaphragm, which is used to achieve much larger deformation than conventional silicon diaphragms under low pressure. The larger deformation of the PDMS diaphragm provides higher sensitivity than silicon-based pressure sensors because of the lower Young’s modulus of the PDMS diaphragm. The great advantage of the PDMS diaphragm with respect to sensitivity was confirmed through the use of the numerical simulation method and through the conduct of basic experiments. A carbon fibre 10 μm in diameter was used to sense the strain change that had been induced on the diaphragm during its operation. The optimal position of the carbon fibre in the PDMS diaphragm was determined using the numerical analysis method. The carbon fibre was exactly formed across the Al electrodes in the diaphragm through dielectrophoresis. The replacement of the piezoresistor material provided some advantages, such as easy fabrication and a high gauge factor. Several types of pressure sensors with a PDMS diaphragm were fabricated, and the feasibility of such pressure sensors was evaluated.