Insights into Materials, Physics, and Applications in Flexible and Wearable Acoustic Sensing Technology

Abstract

Sound plays a crucial role in the perception of the world. It allows to communicate, learn, and detect potential dangers, diagnose diseases, and much more. However, traditional acoustic sensors are limited in their form factors, being rigid and cumbersome, which restricts their potential applications. Recently, acoustic sensors have made significant advancements, transitioning from rudimentary forms to wearable devices and smart everyday clothing that can conform to soft, curved, and deformable surfaces or surroundings. In this review, the latest scientific and technological breakthroughs with insightful analysis in materials, physics, design principles, fabrication strategies, functions, and applications of flexible and wearable acoustic sensing technology are comprehensively explored. The new generation of acoustic sensors that can recognize voice, interact with machines, control robots, enable marine positioning and localization, monitor structural health, diagnose human vital signs in deep tissues, and perform organ imaging is highlighted. These innovations offer unique solutions to significant challenges in fields such as healthcare, biomedicine, wearables, robotics, and metaverse. Finally, the existing challenges and future opportunities in the field are addressed, providing strategies to advance acoustic sensing technologies for intriguing real‐world applications and inspire new research directions.

Intelligent, Flexible Artificial Throats with Sound Emitting, Detecting, and Recognizing Abilities

“…For some electrical conductors with the same physical property when measured in different directions, the relative resistance change can be derived as where describes the length of the electrical conductor, is Possion’s ration of the electrical conductor, and is the resistivity. As described in this formula, the change of the length and the variance of the determine the change of resistance [ 54 , 57 ].…”

“…However, the current AT still have problems such as sensitivity and accuracy, which need to be further improved. Additionally, optimal performance and durability during use also need to be focused [ 57 ].…”

“…where 𝑙 describes the length of the electrical conductor, 𝑣 is Possion's ration of the electrical conductor, and 𝜌 is the resistivity. As described in this formula, the change of the length ∆𝑙 and the variance of the 𝜌 ∆𝜌 determine the change of resistance ∆𝑅 [54,57].…”

“…where l describes the length of the electrical conductor, v is Possion's ration of the electrical conductor, and ρ is the resistivity. As described in this formula, the change of the length (∆l) and the variance of the ρ (∆ρ) determine the change of resistance (∆R) [54,57]. As depicted in Figure 7a, the application of an external force induces compressive deformation in the sensor within increasing material contact, which creates additional conductive paths and varying resistance.…”