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

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.

Piezoelectric fibers for flexible and wearable electronics.

Flexible and wearable electronics represent paramount technologies offering revolutionized solutions for medical diagnosis and therapy, nerve and organ interfaces, fabric computation, robot-in-medicine and metaverse. Being ubiquitous in everyday life, piezoelectric materials and devices play a vital role in flexible and wearable electronics with their intriguing functionalities, including energy harvesting, sensing and actuation, personal health care and communications. As a new emerging flexible and wearable technology, fiber-shaped piezoelectric devices offer unique advantages over conventional thin-film counterparts. In this review, we survey the recent scientific and technological breakthroughs in thermally drawn piezoelectric fibers and fiber-enabled intelligent fabrics. We highlight the fiber materials, fiber architecture, fabrication, device integration as well as functions that deliver higher forms of unique applications across smart sensing, health care, space security, actuation and energy domains. We conclude with a critical analysis of existing challenges and opportunities that will be important for the continued progress of this field.

A 'Moore's law' for fibers enables intelligent fabrics.

Fabrics are an indispensable part of our everyday life. They provide us with protection, offer privacy and form an intimate expression of ourselves through their esthetics. Imparting functionality at the fiber level represents an intriguing path toward innovative fabrics with a hitherto unparalleled functionality and value. The fiber technology based on thermal drawing of a preform, which is identical in its materials and geometry to the final fiber, has emerged as a powerful platform for the production of exquisite fibers with prerequisite composition, geometric complexity and control over feature size. A 'Moore's law' for fibers is emerging, delivering higher forms of function that are important for a broad spectrum of practical applications in healthcare, sports, robotics, space exploration, etc. In this review, we survey progress in thermally drawn fibers and devices, and discuss their relevance to 'smart' fabrics. A new generation of fabrics that can see, hear and speak, sense, communicate, harvest and store energy, as well as store and process data is anticipated. We conclude with a critical analysis of existing challenges and opportunities currently faced by thermally drawn fibers and fabrics that are expected to become sophisticated platforms delivering value-added services for our society.

Facile Synthesis of Amorphous MoCo Lamellar Hydroxide for Alkaline Water Oxidation.

To find an oxygen evolution reaction (OER) catalyst with satisfactory catalytic performance and affordable cost is of great importance to the development of many new energy devices. In this work, a simple and effective strategy was developed to synthesize a series of amorphous MoCo lamellar hydroxide through one-step chemical co-precipitation. Systematic investigations showed that different functional agents (2-methylimidazole, NaOH, NH4 OH) in the fabrication process resulted in different micromorphology of the catalyst, thus influencing its electrocatalytic performance. Also, adding various amounts of Mo could influence the intrinsic catalytic properties. Samples synthesized with appropriate functional agent addition and optimized Mo addition exhibited amorphous nature and bent nanosheet morphology, as well as highest intrinsic catalytic activity, showing a low overpotential of 290 mV at 10 mA cm-2 and a small Tafel slope of 55 mV dec-1 in 1 m KOH solution. Additionally, the catalytic performance of the sample showed just small decay after 50 h chronopotentiometry test and 3000 cyclic voltammetry cycles, exhibiting the ultra-stable catalytic activity of the catalyst. This work provides a possible large-scale commercial production strategy of OER catalysts with promising performance and low fabrication cost.