Highly Transparent, Flexible, and Self-Healable Thermoacoustic Loudspeakers
Donghee Kang, Seungse Cho, Sujin Sung, Young‐Ryul Kim, Hyejin Lee, Ayoung Choe, Jeonghee Yeom, Minsoo P. Kim, Jin Chul Kim, Seung Man Noh, Hyunhyub Ko
Abstract
Thermoacoustic (TA) loudspeakers have garnered significant attention in recent times as a novel film speaker that utilizes temperature oscillation to vibrate the surrounding air. Conventional film-type TA loudspeakers are known to experience problems when external environments damage their conductive networks, causing them to malfunction. Therefore, introducing self-healing polymers in TA loudspeakers could be an effective way to restore the surface damage of conductive networks. In this study, we present transparent, flexible, and self-healable TA loudspeakers based on silver nanowire (AgNW)-poly(urethane-hindered urea) (PUHU) conductive electrodes. Our self-healable AgNW/PUHU electrodes exhibit significant self-healing for repairing the surface damages that are caused due to the dynamic reconstruction of reversible bulky urea bonds in PUHU. The fabricated self-healable TA loudspeakers generate a sound pressure level of 61 dB at 10 kHz frequency (alternating current (AC) 7 V/direct current (DC) 1 V). In particular, the TA speakers are able to recover the original sound after healing the surface damages of electrodes at 95 °C and 80% relative humidity within 5 min. We believe that the technique proposed in this study provides a robust and powerful platform for the fabrication of transparent and flexible TA loudspeakers with excellent self-healing, which can be applied in flexible and wearable acoustic electronics.