Mutually Reinforced Polymer-Graphene Bilayer Membrane for Energy-Efficient Acoustic Transduction

We present a lightweight, flexible, transparent, and conductive bilayer composite of polyimide and single-layer graphene suspended on the centimeter scale with an unprecedentedly high aspect-ratio of 1e5. The coupling of the two components leads to mutual reinforcement and creates an ultra-strong membrane that supports 30,000 times its own weight. Upon electromechanical actuation, the membrane pushes a massive amount of air and generates high-quality acoustic sound. The energy efficiency is ~10-100 times better than state-of-the-art electrodynamic speakers. The bilayer membrane’s combined properties of electrical conductivity, mechanical strength, optical transparency, thermal stability, and chemical resistance will promote applications in electronics, mechanics, and optics.