Inkjet printed all-polymer flexural plate wave sensors

We demonstrate an all-polymer flexural-plate-wave gravimetric sensor using piezoelectric PVDF and conductive PEDOT:PSS. An inkjet-printed interdigital transducer (IDT) is used to excite Lamb waves within the film that are measured both electronically, using a second IDT, and mapped directly using a scanning laser Doppler vibrometer. Pulsed wave excitation isolates the weak acoustic signal from the electromagnetic crosstalk, enabling the measurement of relative changes in the resonant frequency, Δf/f₀, with the addition of mass, Δm, to the sensing area. A gravimetric mass sensitivity equivalent to Δf/(f₀Δm) = -153 cm²/g has been measured for mass loading with a polymer layer.