G. Liu
Virginia Tech,
United States
Keywords: polymer composite, thin film, graphene, electromechanical, accoustic
Summary:
I will present the design of a new polymer nanocomposite membrane for highly energy-efficient speakers. Membranes are ubiquitous in natural and man-made systems including ears and drums. Emerging technologies demand for membranes that are ultrathin but over an ultra-large area. Additionally, the membranes must be flexible, lightweight, transparent, conductive, tensioned, and free-standing. The construction and actuation of these membranes, however, has been challenging. Here we show a bilayer membrane of polymer and single layer graphene that is free-standing, highly tensioned, flexible, lightweight, transparent, and conductive and has an unprecedentedly high aspect-ratio of 105. Separately, neither the single-atom-thick graphene nor the polymer layer survives suspension over inch scale, let alone repeated mechanical deformation. After integration, the two components mutually reinforce each other and support 30,000 times their own weight. Upon electromechanical actuation, the membrane pushes a massive amount of air and generates high-quality acoustic sound, and it is 100 times more energy efficient than state-of-the-art electrodynamic speakers. The new bilayer polymer composite will impact a plethora of fields and enable next-generation technologies in acoustics, electronics, mechanics, optics, and chemistry.