Preparation and application of flexible carbon nanofiber membranes via electrospinning: from stress dispersion to multifunctionality
Related Articles
Electro-spun nanofibers-based triboelectric nanogenerators in wearable electronics: status and perspectives
Electro-Spun nanofibers (ESNs), with their design flexibility, tailorable morphologies, and high surface area, are well-favored as triboelectric nanogenerator (TENG) materials for wearable electronics. Here, various aspects of ESNs-based wearable TENGs were examined. After introducing the most common TENG operating modes, an insightful overview of wearable TENG applications based on ESNs was presented. In this survey, a special attention is paid to wearable sensing, human-machine interaction, self-powered devices, and amplified energy harvesting. Efforts towards improving energy conversion efficiency, material durability, and compatibility with diverse wearable platforms were visited. Finally, a perspective based on particularly material aspect of ESNs is given, which could be insightful in tackling prevailing challenges and giving birth to new directions.
Revolutionizing wearable technology: advanced fabrication techniques for body-conformable electronics
With the increasing demand for wearable electronic products, there is a pressing need to develop electronic devices that seamlessly conform to the contours of the human body while delivering excellent performance and reliability. Traditional rigid electronic fabrication technologies fall short of meeting these requirements, necessitating the exploration of advanced flexible fabrication technologies that offer new possibilities for designing and fabricating flexible and stretchable electronic products, particularly in wearable devices. Over time, the continuous development of innovative fabrication techniques has ushered in significant improvements in the design freedom, lightweight, seamless integration, and multifunctionality of wearable electronics. Here, we provide a comprehensive overview of the advancements facilitated by advanced fabrication technology in wearable electronics. It specifically focuses on key fabrication methods, including printed electronics fabrication, soft transfer, 3D structure fabrication, and deformation fabrication. By highlighting these advancements, it sheds light on the challenges and prospects for further development in wearable electronics fabrication technologies. The introduction of advanced fabrication technologies has revolutionized the landscape of wearable/conformable electronics, expanding their application domains, streamlining system complexity associated with customization, manufacturing, and production, and opening up new avenues for innovation and development of body-conformable electronics.
Development of composite electrolyte membranes with functional polymer nanofiber frameworks
Solid electrolyte membranes based on polymers have shown promise owing to their high-energy demand and the sustainable and cost-effective nature of these materials. However, polymer electrolyte membranes composed of a polymer matrix have not progressed for the following reasons: (1) the low ion conductivity of polymer materials cannot achieve the level required for practical use, and (2) it is difficult to satisfy both battery performance and membrane durability simultaneously because of the trade-offs between ion conductivity and membrane stability. In recent years, research on composite electrolyte membranes composed of polymer nanofibers and a polymer matrix has attracted significant interest because of their improved ion conductivity, excellent membrane durability, and ability to fabricate thinner membranes. Polymeric nanofiber-containing polymer electrolyte membranes are expected to be applied not only to electrolyte membranes for fuel cells and water electrolysis, including alkaline-type electrolyte membranes for water electrolysis, but also to all-solid-state Li-ion batteries and all-solid-state Li-air batteries. This focus review presents the latest information on these topics.
Biomimetic freestanding microfractals for flexible electronics
The microfractals of leaf skeletons can be effective substrates for flexible electronics due to their high surface-to-volume ratio, transparency, breathability and flexibility. The challenge lies in replicating these fractal surfaces at the microscale in a way that is scalable, freestanding, and integrable with various materials. In this study, we present a novel method for the biomimetic microfabrication of leaf-skeleton-based fractal surfaces. We utilized a modified electrospinning method, replacing the fiber collector with a metalized biotic collector to replicate the microstructures. The biomimetic microfractals demonstrated ~90% replication accuracy, >80% transparency, good stretchability, and breathability, and were freestanding. The method is versatile, allowing for the use of a wide range of polymers in biomimetic microfabrication. For application in flexible electronics, biomimetic conductive fractal patterns (BCFP) were fabricated by immobilizing Ag Nanowires (AgNW) using a simple spray-based method. The BCFP exhibited high conductivity with sheet resistances <20 Ω sq–1 while maintaining good transparencies. The BCFP adheres conformally to human skin, acting as an electronic skin (e-skin). To demonstrate the application, the BCFP was used to fabricate a tactile pressure sensor. In addition to their excellent transparency at low sheet resistances, stretchability, moisture resistance, and tight conformal bonding with the target surface, the BCFP also allows the evaporation of perspiration, making them suitable for long-term use as epidermal sensors. The application of BCFP in advanced bionic skin was demonstrated through gesture monitoring experiments.
Flexible micromachined ultrasound transducers (MUTs) for biomedical applications
The use of bulk piezoelectric transducer arrays in medical imaging is a well-established technology that operates based on thickness mode piezoelectric vibration. Meanwhile, advancements in fabrication techniques have led to the emergence of micromachined alternatives, namely, piezoelectric micromachined ultrasound transducer (PMUT) and capacitive micromachined ultrasound transducer (CMUT). These devices operate in flexural mode using piezoelectric thin films and electrostatic forces, respectively. In addition, the development of flexible ultrasound transducers based on these principles has opened up new possibilities for biomedical applications, including biomedical imaging, sensing, and stimulation. This review provides a detailed discussion of the need for flexible micromachined ultrasound transducers (MUTs) and potential applications, their specifications, materials, fabrication, and electronics integration. Specifically, the review covers fabrication approaches and compares the performance specifications of flexible PMUTs and CMUTs, including resonance frequency, sensitivity, flexibility, and other relevant factors. Finally, the review concludes with an outlook on the challenges and opportunities associated with the realization of efficient MUTs with high performance and flexibility.
Responses