Annealed Pyrolytic Graphitic Carbon Electrodes for Piezoelectric Acoustic Nanoweb

The primary challenge in realizing an ultimate lightweight and flexible acoustic sensing device is the electrode material. To obtain the best device performance expensive gold electrodes have been used in the literature due to the relatively higher electrical conductivity. In this paper we implement an annealed pyrolytic graphitic carbon on carbon fibers to form a low-cost highly performing porous electrode for acoustic applications. The electrode is prepared by using a 400-micron thick PMMA membrane electrospun on a unidirectional carbon fiber textile. The electrode is then used to form an acoustic sensor via a hybrid 3D printing-electrospinning-pyrolysis approach which allowed to deliver an overall flexible acoustic device. Preliminary results show a low noise level functional material with reasonably high electromechanical output to a wide range of acoustic frequencies. The higher sensitivity of the material with respect to the devices formed with continuous electrodes, is to be attributed to the porosity of the electrode material which enhances the vibrating air particles to interact with the interacting membrane directly and homogenously.