A Flexible Loudspeaker Using the Movement of Liquid Metal Induced by Electrochemically Controlled Interfacial Tension. Issue 51 (25th November 2019)

• Record Type: Journal Article
• Authors: Jin, Sang Woo; Jeong, Yu Ra; Park, Heun; Keum, Kayeon; Lee, Geumbee; Lee, Yong Hui; Lee, Hanchan; Kim, Min Su; Ha, Jeong Sook
• Is Part Of: Small. Volume 15:Issue 51(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-11-25
• Subjects: acoustic device -- electrochemical wetting -- flexible loudspeaker -- interfacial tension -- liquid metal; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.201905263
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract: A flexible liquid metal loudspeaker (LML) is demonstrated consisting of a gallium‐based eutectic liquid metal (Galinstan) and basic aqueous electrolyte (NaOH(aq) ). The LML is driven by liquid metal motion induced by the electrochemically controlled interfacial tension of the Galinstan in NaOH(aq) electrolyte under an applied alternating current (AC) voltage. The fabricated LML produces sound waves in the human audible frequency band with a sound pressure level of ≈40–50 dB at 1 cm from the device and exhibits mechanical stability under bending deformation with a bending radius of 3 mm. Various sounds can be generated with the LML from a single tone to piano notes and human voices. To understand the underlying mechanism of sound generation by the LML, motion analyses, sound measurements, and electrical characterization are conducted at various frequencies. For the first time, this work suggests a new type of liquid metal‐based electrochemically driven sound generator in the field of flexible acoustic devices that can be applied to future wearable electronics. Abstract : A flexible liquid metal loudspeaker based on the motion of Galinstan induced by electrochemically controlled interfacial tension under an applied AC voltage is successfully developed for the first time. The fabricated device can form audible sound pressure even in a mechanically deformed state and is applicable to future flexible acoustic devices for wearable electronics.