Viscoelastic Response of Graphene Oxide‐Based Membranes and Efficient Broadband Sound Transduction
Kaiwen Hu, William Cárdenas, Yi‐Chi Huang, Huijing Wei, R. Gaskell, Eli Martel, Marta Cerruti, Thomas Szkopek
Abstract
Abstract Freestanding micrometer thick graphene oxide (GO) membranes combine high stiffness, low mass density, and high loss coefficient. This unique combination of properties is ideal for efficient and broadband electro‐acoustic transduction, relying on membrane lightness, stiffness, and internal damping. Here, the viscoelastic response of GO membranes is measured, and the application of ≈100 µm thick GO membranes is demonstrated in dynamic loudspeakers. Using dynamic mechanical analysis and the time‐temperature superposition principle of polymer rheology, it is found that the stiffness of GO membrane increases by more than 50% over 1–20 kHz while damping decreases by less than 20%. GO membranes exhibit 45% higher damping than aluminum membranes in loudspeakers assemblies. Consequently, GO membranes enable the upshift of loudspeaker breakup frequency by octave above speakers assembled with aluminum, polyethylene terephthalate, titanium, and oak wood membranes. GO is thus found to be an exceptional material for electro‐acoustic transduction.