Carbon nanotube film piezoresistors embedded in polymer membranes

We present carbon nanotube film (CNF) piezoresistors embedded in polymer membranes. CNFs by vacuum filtration are patterned on an Au-deposited Si-wafer and transferred onto the poly-dimethylsiloxane (PDMS) using the weak adhesion property between Au-layer and Si-wafer. Transmittance and I-V characteristic are measured to confirm transferred CNFs as transparent electrodes. The pressure sensor consists of CNF piezoresistors embedded in 130 mu m thick circular PDMS membranes. The gauge factor of CNFs at different thickness is obtained around 10-20 when the resistance increases from 2.7 to 5.6 k with applied pressure, which shows that CNFs can be used as transparent piezoresistors in polymer-based microelectromechanical systems.