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Theory and experiment for 3D porous graphene foam thermoacoustic transducer

Due to its excellent heat dissipation capability and high thermal conductivity, 3D porous graphene foam (3DPGF) has attracted immense attention for its potential applications in thermoacoustic devices. However, 3DPGF is usually relatively fragile, which poses a challenge to its practical application in thermoacoustic equipment. In this respect, its structural strength can be significantly improved by pasting the material onto a substrate. In this paper, the performance of thermoacoustic transducers made of 3DPGF on a substrate is investigated by theory and experiment. Both 3DPGFs on a porous anodic aluminum (AAO) substrate and on a polydimethylsiloxane (PDMS) substrate are taken into consideration. First, a theoretical model for the 3D thermoacoustic source on a substrate is proposed, and analytical solutions are obtained. The model and its corresponding solution are verified by comparing it with experiment. Subsequently, key influencing factors of 3DPGF and substrate on the acoustic field characteristics are analyzed theoretically. Finally, an experimental bending test is performed to explore the acoustic performance and flexibility of 3DPGFs on different substrates. The theoretical and experimental results reveal that 3DPGF on AAO produces a higher sound pressure level than that on PDMS substrate when the thermoacoustic transducer is undeformed, while it is easily damaged at an initial first-time bending. In contrast, 3DPGF on PDMS shows better flexibility than that on AAO substrate and it displays stable acoustic performance even after repeated and recursive bending.