The eardrum, also called the tympanic membrane or myringa is a thin, cone-shaped membrane that play the crucial role in sensing sound and transmit the sound from the air to the ossicles. In current microphone industry, a rigid diaphragm which consist of metal film or Si membrane is used to fulfill acoustic-electric transition. Although the diaphragm is able to respond sound, the stiff and brittle configuration may limited its further application in vivo implantation. It is necessary to fabricate a bionic flexible eardrum which can respond and record sound with similar flexible mechanic properties, wide frequency response domain, high sensitivity and ultra-fast response time.
Recently, Professor ZHANG Ting and his group from the Suzhou Institute of Nanotech and Nanobionics (SINANO), Chinese Academy of Sciences (CAS), developed an ultra-thin flexible electronic eardrum to detect sound signal by optimizing the chosen materials and micro-structure design of the device.
To realize the thin and elastic property, the polydimethylsiloxane (PDMS) was spin-coated on to the uniformly micro-structured Si mold on which sensing nanomaterials are deposited and co-curing with the ultra-violet treated polyethylene (PE) film. The flexible electronic eardrum (50 μm thick) can detect and record sound with high signal to noise ratio (~ 55 dB), fast response time (76.9 μs), and wide frequency response (20-13000 Hz) even after 150,000 times cycling pressure test. The sensors have a high degree of consistency with the original audio signal and can identify the sound of different people. The result has been published in the latest issue of Nano Research.
Prof. ZHANG Ting, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences
Reference: Flexible electronic eardrum