Research on wearable electronic devices that can be directly integrated into daily textiles or clothes has been explosively grown holding great potential for various practical wearable applications. ...These wearable electronic devices strongly demand 1D electronic devices that are light–weight, weavable, highly flexible, stretchable, and adaptable to comport to frequent deformations during usage in daily life. To this end, the development of 1D electrodes with high stretchability and electrical performance is fundamentally essential. Herein, the recent process of 1D stretchable electrodes for wearable and textile electronics is described, focusing on representative conductive materials, fabrication techniques for 1D stretchable electrodes with high performance, and designs and applications of various 1D stretchable electronic devices. To conclude, discussions are presented regarding limitations and perspectives of current materials and devices in terms of performance and scientific understanding that should be considered for further advances.
1D stretchable electrodes and electronic devices are of great importance for developing advanced wearable electronics in the form of daily clothes. The state‐of‐the‐art advances in stretchable conductive fibers are systematically introduced in terms of their conductive materials, fabrication techniques, electronic devices, and applications. An outlook and challenges for future research are also provided.
•Fabrication of facile, scalable bio-mimicking hierarchical micro-nanostructure.•Capacitive pressure sensors show a high sensitivity and fast response time.•Capability for pulse monitoring at the ...human wrist with the bilayer pressure sensor.•Promising for the soft electronics and potential in electronic skin applications.
Capacitive pressure sensors are an important part of flexible/stretchable electronic skin applications. The fabrication of most of the reported polydimethylsiloxane (PDMS) based capacitive pressure sensors involves complex techniques and expensive tools. To improve the capacitive sensing properties of PDMS, a bio-mimicking hierarchical micro- and nanostructure that are facile, cost-effective, and scalable is presented in this work. Red rose petals are known to consist of hierarchical micropapillae and nanofolds. So, the artificial fabrication of these micro- and nanostructures provides a necessary roughness for pressure sensors. The sensors comprise both single and double layers of well-defined PDMS structures with indium tin oxide (ITO) electrodes. This capacitive pressure sensor allows the sensitive detection of both static and dynamic external stimuli. By successfully mimicking rose petals whose hemisphere contains micropapillae and nanofolds, ultra-sensitive capacitive pressure sensors show a sensitivity of 0.055 kPa−1 over a wide pressure range (0.5–10 kPa) with a fast response time (<200 ms) and high stability. The sensing performance also checked for capability to accurately pulse monitoring at the human wrist which demonstrated the bilayer pressure sensor has promising application in wearable electronics.
A flexible and sensitive textile‐based pressure sensor is developed using highly conductive fibers coated with dielectric rubber materials. The pressure sensor exhibits superior sensitivity, very ...fast response time, and high stability, compared with previous textile‐based pressure sensors. By using a weaving method, the pressure sensor can be applied to make smart gloves and clothes that can control machines wirelessly as human–machine interfaces.
Semiconducting two-dimensional (2D) transition metal dichalcogenides (TMDCs) are promising gas-sensing materials due to their large surface-to-volume ratio. However, their poor gas-sensing ...performance resulting from the low response, incomplete recovery, and insufficient selectivity hinders the realization of high-performance 2D TMDC gas sensors. Here, we demonstrate the improvement of gas-sensing performance of large-area tungsten disulfide (WS2) nanosheets through surface functionalization using Ag nanowires (NWs). Large-area WS2 nanosheets were synthesized through atomic layer deposition of WO3 followed by sulfurization. The pristine WS2 gas sensors exhibited a significant response to acetone and NO2 but an incomplete recovery in the case of NO2 sensing. After AgNW functionalization, the WS2 gas sensor showed dramatically improved response (667%) and recovery upon NO2 exposure. Our results establish that the proposed method is a promising strategy to improve 2D TMDC gas sensors.
This study evaluated whether phosphorus in an aqueous solution can be effectively adsorbed and removed by sulfuric acid (SA)-coated vermiculite (SCV), which was synthetized by heating a mixture of ...expanded vermiculite (EV) and SA at 300°C. Phosphorus was removed from the aqueous solution and removal characteristics were evaluated by batch kinetic, batch adsorption, and column tests. The phosphate removal rates (h-1) for 1, 2.5, 5, 7.5, 12.5, and 25 g·L-1 of SCV were 0.00015, 0.0011, 0.0044, 0.0087, 0.0648, and 0.5002, respectively. The Qmax of the Langmuir model and the partition coefficients of the linear and Freundlich models were 8.92 mg·g-1, 0.65 L·g-1, and 4.60 L·g-1 (1/n = 0.354), respectively. The equilibrium phosphorus adsorptions (qe) were 7.47, 14.69, and 19.53 mg·g-1 at initial concentrations of 10, 25, and 50 mg·L-1, respectively. These results show that SCV can efficiently adsorb phosphorus in an aqueous solution.
Stretchable conductive fibers have received significant attention due to their possibility of being utilized in wearable and foldable electronics. Here, highly stretchable conductive fiber composed ...of silver nanowires (AgNWs) and silver nanoparticles (AgNPs) embedded in a styrene–butadiene–styrene (SBS) elastomeric matrix is fabricated. An AgNW‐embedded SBS fiber is fabricated by a simple wet spinning method. Then, the AgNPs are formed on both the surface and inner region of the AgNW‐embedded fiber via repeated cycles of silver precursor absorption and reduction processes. The AgNW‐embedded conductive fiber exhibits superior initial electrical conductivity (σ0 = 2450 S cm−1) and elongation at break (900% strain) due to the high weight percentage of the conductive fillers and the use of a highly stretchable SBS elastomer matrix. During the stretching, the embedded AgNWs act as conducting bridges between AgNPs, resulting in the preservation of electrical conductivity under high strain (the rate of conductivity degradation, σ/σ0 = 4.4% at 100% strain). The AgNW‐embedded conductive fibers show the strain‐sensing behavior with a broad range of applied tensile strain. The AgNW reinforced highly stretchable conductive fibers can be embedded into a smart glove for detecting sign language by integrating five composite fibers in the glove, which can successfully perceive human motions.
Ag nanowire reinforced highly stretchable conductive fiber is developed using simple wet spinning method, which consists of silver nanowires and nanoparticles embedded in elastomeric polymer matrix. The composite fiber can preserve its electrical property under large strain and has superior strain‐sensing behavior. It can be utilized in the wearable smart glove for detecting human motions such as sign language.
Global Navigational Satellite System (GNSS) technologies are actively being developed to address the demand for enhanced positional accuracy. Smartphones are the most prevalent GNSS receiver today ...and have garnered attention thanks to improved positional accuracy and usability that can be accessed at an affordable price. In a forested environment, multipath error can deteriorate the positional accuracy, depending on the state of nearby vegetation. Therefore, this study was conducted to investigate the impacts of the size and location of vegetation on positional accuracy of GNSS receivers to determine whether the errors observed are systematic. Twenty-six control points within the Whitehall Forest GPS Test site in Athens, Georgia were used to evaluate positional accuracy of three different GNSS receivers (two traditional handheld GNSS receivers (including Garmin and Trimble receivers) and a smartphone). Thirty-five forest variables were developed from information around each control point to conduct a correlation analysis with observed horizontal position error in the positions determined by each device. In this study, we confirmed that the positional error of the smartphone was significantly lower than the Garmin receiver, and similar, but significantly different than the positional error observed by the Trimble receiver. It was confirmed that correlations between forest variables and horizontal position error regardless of the GNSS receiver employed were significant, yet trends were not consistent. The effect of the size of nearby trees on horizontal position error could not be generalized; however, the location of nearby trees on horizontal position error could.
Recent advances in diagnostics and medicines emphasize the spatial and temporal aspects of monitoring and treating diseases. However, conventional therapeutics, including oral administration and ...injection, have difficulties meeting these aspects due to physiological and technological limitations, such as long‐term implantation and a narrow therapeutic window. As an innovative approach to overcome these limitations, electronic devices known as electronic drugs (e‐drugs) have been developed to monitor real‐time body signals and deliver specific treatments to targeted tissues or organs. For example, ingestible and patch‐type e‐drugs could detect changes in biomarkers at the target sites, including the gastrointestinal (GI) tract and the skin, and deliver therapeutics to enhance healing in a spatiotemporal manner. However, medical treatments often require invasive surgical procedures and implantation of medical equipment for either short or long‐term use. Therefore, approaches that could minimize implantation‐associated side effects, such as inflammation and scar tissue formation, while maintaining high functionality of e‐drugs, are highly needed. Herein, the importance of the spatial and temporal aspects of medical treatment is thoroughly reviewed along with how e‐drugs use cutting‐edge technological innovations to deal with unresolved medical challenges. Furthermore, diverse uses of e‐drugs in clinical applications and the future perspectives of e‐drugs are discussed.
Electronic drugs (e‐drugs) for spatial and temporal medical treatment of human diseases are of great importance for the development of advanced biomedical integrated devices to solve unmet medical challenges. State‐of‐the‐art advances in e‐drugs are systematically introduced in terms of their device types and targeting diseases. An outlook and the challenges for future research are also provided.
Biological creatures with unique surface wettability have long served as a source of inspiration for scientists and engineers. More specifically, materials exhibiting extreme wetting properties, such ...as superhydrophilic and superhydrophobic surfaces, have attracted considerable attention because of their potential use in various applications, such as self-cleaning fabrics, anti-fog windows, anti-corrosive coatings, drag-reduction systems, and efficient water transportation. In particular, the engineering of surface wettability by manipulating chemical properties and structure opens emerging biomedical applications ranging from high-throughput cell culture platforms to biomedical devices. This review describes design and fabrication methods for artificial extreme wetting surfaces. Next, we introduce some of the newer and emerging biomedical applications using extreme wetting surfaces. Current challenges and future prospects of the surfaces for potential biomedical applications are also addressed.
A flexible pressure sensor with high performances is one of the promising candidates for achieving electronic skins (E‐skin) related to various applications such as wearable devices, health ...monitoring systems, and artificial robot arms. The sensitive response for external mechanical stimulation is fundamentally required to develop the E‐skin which imitates the function of human skin. The performance of capacitive pressure sensors can be improved using morphologies and structures occurring in nature. In this work, highly sensitive capacitive pressure sensors based on a porous structure of polydimethylsiloxane (PDMS) thin film, inspired on the natural multilayered porous structures seen in mushrooms, diatoms, and spongia offilinalis, have been developed and evaluated. A bioinspired porous dielectric layer is used, resulting in high‐performance pressure sensors with high sensitivity (0.63 kPa−1), high stability over 10 000 cycles, fast response and relaxation times, and extremely low‐pressure detection of 2.42 Pa. Additionally, the resulting pressure sensors are demonstrated to fabricate multipixel arrays, thus achieving successful real‐time tactile sensing of various touch shapes. The developed high‐performance flexible pressure sensors may open new opportunities for innovative applications in advanced human‐machine interface systems, robotic sensory systems, and various wearable health monitoring devices.
A highly sensitive bioinspired porous structured pressure sensor is demonstrated that can detect extremely light weight objects such as an ant. The porous structured pressure sensor is pixelated into a 15 × 15 array and based on the fast response time of the pressure sensor, real‐time tactile mapping is demonstrated under various pressures.
PDF
