Wearable,Human‐Interactive,Health‐Monitoring,Wireless Devices Fabricated by Macroscale Printing Techniques

Wearable human‐interactive devices are advanced technologies that will improve the comfort, convenience, and security of humans, and have a wide range of applications from robotics to clinical health monitoring. In this study, a fully printed wearable human‐interactive device called a “smart bandage” is proposed as the first proof of concept. The device incorporates touch and temperature sensors to monitor health, a drug‐delivery system to improve health, and a wireless coil to detect touch. The sensors, microelectromechanical systems (MEMS) structure, and wireless coil are monolithically integrated onto flexible substrates. A smart bandage is demonstrated on a human arm. These types of wearable human‐interactive devices represent a promising platform not only for interactive devices, but also for flexible MEMS technology.     

The underlying factors of the perceived usefulness of using smart wearable devices for disaster applications

Smart wearable devices offer much potential to assist citizens in disasters. To the general public, however, using these devices for disaster applications is still a novel concept. In disasters, most people are reluctant to rely on unfamiliar technologies. Thus, for these devices to become truly useful in disasters, it is important to understand factors that affect their acceptance by the public. Previous studies show that perceived usefulness is a clear antecedent of people’s acceptance of smart wearable devices. However, the underlying factors that affect perceived usefulness itself are not clearly known. Thus, the aim of this study is to fill this gap, and by doing so, to derive some practical implications for solution developers and governments.This study used structural equation modelling to analyse survey data collected from 647 respondents in Japan. We found that the respondents’ perceived usefulness of the current applications of smart wearable devices was a strong predictor of their perceived usefulness of using these devices for disaster applications. Although indirect factors such as the ownership of ICT gadgets and the usage of social media also had some influences, most of their effects were mediated through increasing the respondents’ perceived usefulness of the current applications. In other words, through appreciating the functions of the current applications of smart wearable devices, people can visualise the usefulness of these devices in disaster situations. That being said, we found that in parallel, people also had concerns on the privacy issues of these devices. These findings shed light on the promotion and development of this fast growing technology for disaster applications.     

基于大数据分析的电话手表用户画像及应用研究

智能穿戴设备逐渐走进用户的生活,目前儿童电话手表领跑智能穿戴市场。超过1亿人规模的幼儿园儿童及小学生群体是儿童电话手表的受众群体,可作为运营商新用户发展的目标人群。基于用户侧计费账单、计费详单及终端库等数据,对儿童电话手表用户的画像进行了深入研究,并基于研究结果在儿童电话手表及智能穿戴市场的发展和网络方面提出了建议。     

Untethered Feel-Through Haptics Using 18-µm Thick Dielectric Elastomer Actuators

Head-mounted displays for virtual reality (VR) and augmented reality (AR) allow users to see highly realistic virtual worlds. The wearable haptics that enable feeling and touching these virtual objects are typically bulky, tethered, and provide only low fidelity feedback. A particularly challenging type of wearable human-machine interface is feel-through haptics: ultra-thin wearables so soft as to be mechanically imperceptible when turned off, yet generating sufficient force when actuated to make virtual objects feel tangible, or to change the perceived texture of a physical object. Here, 18 µm thick soft dielectric elastomer actuators (DEA), directly applied on the skin, reports rich vibrotactile feedback generation from 1 Hz to 500 Hz. Users correctly identifies different frequency and sequence patterns with success rates from 73 to 97% for devices applied on their fingertips. An untethered version weighing only 1.3 grams allowed blindfolded users to correctly identify letters by “seeing” them through their fingers. The silicone-based DEA membrane is mechanically transparent, enabling wearable haptics for the many applications where hand dexterity is critical. The feel-through DEA can be placed in array format anywhere on the body.     

Power-Free Contact Lens for Glucose Sensing

Recent advances in wearable devices have enabled noninvasive monitoring for healthcare applications. Smart contact lenses have gained substantial attention for medical diagnosis through the analysis of vital signs in tear fluids. However, previous studies have mostly focused on designs embedded with electronic devices or antennas for wireless transmission, which are power-intensive and require external receivers around the ocular system. Here, the study reports a power-free smart contact lens for noninvasive glucose sensing according to the color changes of multiple electrochromic electrodes to achieve direct data transmission without the external wireless system. The device detects various glucose concentrations, from the ordinary range (0.16–0.5 mm ) to abnormally high concentrations (0.9 mm ). The multi-electrode design exhibits acceptable accuracy, with a correlation coefficient r = 0.99543 to the controlled sample and allowed low-glucose detections with concentrations down to 0.05 mm . The device shows good reproducibility, with standard deviations of determined glucose levels of 0.0462 and 0.025 for four continuous cycles and for an interval of several days, respectively. It is believed that the reported smart contact lens has the potential for daily health monitoring by ordinary users without a power supply and external devices. Its simple electronics-free structure will allow for immediate application to the market with cost-effective manufacturing.     

Fake news and COVID-19: modelling the predictors of fake news sharing among social media users

Fake news dissemination on COVID-19 has increased in recent months, and the factors that lead to the sharing of this misinformation is less well studied. Therefore, this paper describes the result of a Nigerian sample (n = 385) regarding the proliferation of fake news on COVID-19. The fake news phenomenon was studied using the Uses and Gratification framework, which was extended by an “altruism” motivation. The data were analysed with Partial Least Squares (PLS) to determine the effects of six variables on the outcome of fake news sharing. Our results showed that altruism was the most significant factor that predicted fake news sharing of COVID-19. We also found that social media users’ motivations for information sharing, socialisation, information seeking and pass time predicted the sharing of false information about COVID-19. In contrast, no significant association was found for entertainment motivation. We concluded with some theoretical and practical implications.     

Indium-tin-oxide,free, flexible,nonvolatile memory devices based on graphene quantum dots sandwiched between polymethylsilsesquioxane layers

Indium-tin-oxide (ITO) free, nonvolatile memory (NVM) devices based on graphene quantum dots (GQDs) sandwiched between polymethylsilsesquioxane (PMSSQ) layers were fabricated directly on polyethylene terephthalate (PET) substrates by using a solution process technique. Current-voltage (I-V) curves for the silver nanowire/PMSSQ/GQD/PMSSQ/poly(3,4-ethylenethiophene):poly(styrene sulfonate)/PET devices at 300 K showed a current bistability. The ON/OFF ratio of the current bistability for the NVM devices was as large as 1 × 10⁴, and the cycling endurance time of the ON/OFF switching for the NVM devices was above 1 × 10⁴ s. The Schottky emission, Poole-Frenkel emission, trapped-charge limited-current, and space-charge-limited current were dominantly attributed to the conduction mechanisms for the fabricated NVM devices based on the obtained I-V characteristics, and energy band diagrams illustrating the “writing” and the “erasing” processes of the devices.     

A Lithium-Salt-Free,Hydrophobic, Solid-State Poly(Ionic Liquid) Electrolyte Enables Rapid Assembly of Unencapsulated,Removable Electrochromic “Window Tint Film”

Electrochromic technology that enables modulation of a material's optical properties by application of an applied voltage is utilized in smart windows. However, avoiding water absorption by lithium salt in the electrolyte necessitates complex encapsulated device assemblies that must be constructed under strict atmosphere conditions and are largely unrepairable. Herein, a lithium-salt-free, hydrophobic, solid-state poly(ionic liquid) electrolyte based on strong C─F bonds that exhibits low polarizability, low moisture absorption, and a wide electrochemical window, allowing the fabrication of unencapsulated electrochromic devices with outstanding long-term cycling and environmental stability are presented. Intimate contact between the electrolyte and the electrode is achieved through integrated in situ polymerization, providing an interface with multiple molecular interactions that impart robust adhesion, efficient ion transport, and excellent stability. To demonstrate the potential of this electrolyte for cost-effective electrochromic smart windows, low-cost (≈110 USD m⁻²), unencapsulated, removable, electrochromic “window tint film” with customizable dimensions and shapes are fabricated.     

Ionoskins: Nonvolatile,Highly Transparent,Ultrastretchable Ionic Sensory Platforms for Wearable Electronics

The primary technology of next‐generation wearable electronics pursues the development of highly deformable and stable systems. Here, nonvolatile, highly transparent, and ultrastretchable ionic conductors based on polymeric gelators [poly(methyl methacrylate‐ran‐butyl acrylate), PMMA‐r‐PBA] and ionic liquids (IL) are proposed. A crucial strategy in the molecular design of polymer gelators is copolymerization of PMMA and IL‐insoluble low glass transition temperature (T_g) polymers that can be deformed and effectively dissipate applied strains. Highly stretchable (elongation limit ≈850%), mechanically robust (elastic modulus ≈3.1 × 10⁵ Pa), and deformation durable (recovery ratio ≈96.1% after 500 stretching/releasing cycles) gels are obtained by judiciously adjusting the molecular characteristics of polymer gelators and gel composition. An extremely simple “ionic” strain sensory platform is fabricated by directly connecting the stretchable gel and a digital multimeter, exhibiting high sensitivity (gauge factor ≈2.73), stable operation (>13 000 cycles), and nonvolatility (>10 d in air). Moreover, the skin‐type strain sensor, referred to as ionoskin, is demonstrated. The gels are attached to a part of the body (e.g., finger, elbow, knee, or ankle) and various human movements are successfully monitored. The ionoskin renders the opportunity to achieve wearable ubiquitous electronics such as healthcare devices and smart textile systems.     

Wearable Integrated Self-Powered Electroluminescence Display Device Based on All-In-One MXene Electrode for Information Encryption

Anti-counterfeiting and visual optical information encryption/decryption technology have attracted widespread attention in the field of information security. Luminescent encryption technologies still face a huge challenge in external high voltage power supply, complex architecture, and expensive decryption equipment, which hinder their broad applications. Herein, a wearable integrated self-powered electroluminescent (EL) display device (W-ELD) that consists of MXene/Silicone-based triboelectric nanogenerator (MS-TENG) and EL device based on a shared MXene electrode is developed for patterned display and information encryption. The W-ELD features an all-in-one MXene electrode with excellent flexibility and high conductivity of 0.6 kΩ sq⁻¹, which is shared by both MS-TENG and EL devices. The MS-TENG demonstrates excellent output performances (output power of 0.9 Wm⁻²) and high stability and durability (10⁴ cycles), which can directly light up the flexible patterned EL device. More importantly, when dripping conductive electrolyte solution, the W-ELD based on “中國”-patterned MXene electrode can precisely reveal the encryption information through self-powered EL emission for real-time visualized information interaction. Consequently, the all-in-one MXene electrode-based W-ELD that integrates both MS-TENG and EL device demonstrates exceptional patterned EL-based information encryption features, which offers a potential prospect in wearable self-powered optoelectronic devices, flexible displays, and encryption technology.     

Organic light-emitting diodes on shape memory polymer substrates for wearable electronics

Green electrophosphorescent organic light-emitting diodes (OLEDs) with inverted top-emitting structures are demonstrated on bio-compatible shape memory polymer (SMP) substrates for wearable electronic applications. The combination of the unique properties of SMP substrates with the light-emitting properties of OLEDs pave to the way for new applications, including conformable smart skin devices, minimally invasive biomedical devices, and flexible lighting/display technologies. In this work, SMPs were designed to exhibit a considerable drop in modulus when a thermal stimulus is applied, allowing the devices to bend and conform to new shapes when its glass transition temperature is reached. These SMP substrates were synthesized using 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione (TATATO), trimethylolpropane tris(3-mercaptopropionate) (TMTMP), and tricyclo[5.2.1.0^2,6]decanedimethanol diacrylate (TCMDA), and show a low glass transition temperature of 43 °C, as measured using dynamic mechanical analysis (DMA). The OLEDs fabricated on these substrates exhibit high performance with a maximum efficacy of 33 cd/A measured at a luminance of 1000 cd/m², and a peak luminance of over 30,000 cd/m².     

Comparison of IGBT short-circuit failure “ohmic mode”: Epoxy molded package versus silicone gel module for new fail-safe and interruptible power converters

An epoxy molded package is compared with a silicone gel module with IGBTs chips in short-circuit failure modes with respect to critical energy, I²T_melting and explosion energy capabilities. Special importance was attached to “ohmic mode” assessment and ageing of the failed chips. The molded technology yields a very low and stable R_sc (<10 mΩ) as a “residual ohmic value” of the dies in low energy short-circuit failure, which is analysed through a complete reverse. Continuous thermal cycling tests over a medium time duration (>1000 h) also exhibit an acceptable drift of the R_sc property (<20%). The silicone gel module clearly exhibits an unstable R_sc value due to damage of the “free moving” wire-bonding on the chips. The authors show that the paralleled wires connections and the multiple parallel melting pits allow a sort of active redundancy and a possible on-state operation. All these results are used for the design of new and original failsafe converters. These topologies use only one paralleled safety leg that is spontaneously and directly connected in series with the failed devices, through the low R_sc value of the failed chips, without any additional complexity or extra cost.     

Smart Clothing: Connecting Human with Clouds and Big Data for Sustainable Health Monitoring

Traditional wearable devices have various shortcomings, such as uncomfortableness for long-term wearing, and insufficient accuracy, etc. Thus, health monitoring through traditional wearable devices is hard to be sustainable. In order to obtain healthcare big data by sustainable health monitoring, we design “Smart Clothing”, facilitating unobtrusive collection of various physiological indicators of human body. To provide pervasive intelligence for smart clothing system, mobile healthcare cloud platform is constructed by the use of mobile internet, cloud computing and big data analytics. This paper introduces design details, key technologies and practical implementation methods of smart clothing system. Typical applications powered by smart clothing and big data clouds are presented, such as medical emergency response, emotion care, disease diagnosis, and real-time tactile interaction. Especially, electrocardiograph signals collected by smart clothing are used for mood monitoring and emotion detection. Finally, we highlight some of the design challenges and open issues that still need to be addressed to make smart clothing ubiquitous for a wide range of applications.     

Double Hydrogen-bonding Reinforced High-Performance Supramolecular Hydrogel Thermocell for Self-powered Sensing Remote-Controlled by Light

Non-contact human-machine interaction is the future trend for wearable technologies. This demand is recently highlighted by the pandemic of coronavirus disease (COVID-19). Herein, an anti-fatigue and highly conductive hydrogel thermocell with photo-thermal conversion ability for non-contact self-powering applications is designed. Double hydrogen-bonding enhanced supramolecular hydrogel is obtained with N-acryloyl glycinamide (NAGA) and diacrylate capped Pluronic F68 (F68-DA) via one-step photo-initiated polymerization. The supramolecular hydrogel can accommodate saturated electrolytes to fulfill the triple function of ionic crosslinking, heat-to-electricity conversion, and light response of thermocell. Eminently, the thermocell stands out by virtue of its high seebeck coefficient (-2.17 mV K⁻¹) and extraordinary toughness (Fatigue threshold ≈ 3120 J m⁻²). The self-powering ability under the control of light heating is explored, and a model of a non-contact “light-remoted” sensor with self-powered and sensing integrated performance remote-controlled by light is constructed. It is believed that this study will pave the way for the non-contact energy supply of wearable devices.     

Thermal-Triggered “On–Off” Switchable Triboelectric Nanogenerator Based on Two-Way Shape Memory Polymer

Developing multifunctional triboelectric nanogenerators (TENGs) with special intelligence is of great significance for next-generation self-powered electronic devices. However, the relevant work on the intelligent TENGs, especially those spontaneously responsive to external stimuli, is rarely reported. Herein, an intelligent TENG with thermal-triggered switchable functionality and high triboelectric outputs is developed by designing a movable triboelectric layer, which is driven by a two-way shape memory polyurethane. The resultant TENG device can be spontaneously switched on/off in response to the environmental temperature change, i.e., switching on at 0 °C and off at 60 °C. At the “on” state, the developed TENG exhibits excellent triboelectric performance with a maximum output power density of 5.15 W m⁻² at a pressure of 30 kPa due to the unique advantages of micro-/nanofiber triboelectric surfaces. Furthermore, the great potential of the switchable TENG in intelligent wearable electronic applications is demonstrated, which can serve as not only the sensing element for monitoring human movement and physical condition in a cold environment but also the thermal-driven switch for turning on/off the heating function on demand. The intelligent “on–off” switchable TENG combined with excellent triboelectric performance may provide new opportunities for future self-powered wearable electronics.     

3D Printed High‐Loading Lithium‐Sulfur Battery Toward Wearable Energy Storage

Wearable electronic devices are the new darling of consumer electronics, and energy storage devices are an important part of them. Here, a wearable lithium‐sulfur (Li‐S) bracelet battery using three‐dimensional (3D) printing technology (additive manufacturing) is designed and manufactured for the first time. The bracelet battery can be easily worn to power the wearable device. The “additive” manufacturing characteristic of 3D printing provides excellent controllability of the electrode thickness with much simplified process in a cost‐effective manner. Due to the conductive 3D skeleton providing interpenetrating transmission paths and channels for electrons and ions, the 3D Li‐S battery can provide 505.4 mAh g^?1 specific capacity after 500 cycles with an active material loading as high as 10.2 mg cm^?1. The practicality is illustrated by wearing the bracelet battery on the wrist and illuminating the red light‐emitting diode. Therefore, the bracelet battery manufactured by 3D printing technology can address the needs of the wearable power supply.     

Polypyrrole/reduced graphene oxide coated fabric electrodes for supercapacitor application

Flexible and wearable energy storage devices are strongly demanded to power smart textiles. Herein, reduced graphene oxide (RGO) and polypyrrole (PPy) were deposited on cotton fabric via thermal reduction of GO and chemical polymerization of pyrrole to prepare textile-based electrodes for supercapacitor application. The obtained PPy–RGO-fabric retained good flexibility of textile and was highly conductive, with the conductivity of 1.2 S cm⁻¹. The PPy–RGO-fabric supercapacitor showed a specific capacitance of 336 F g⁻¹ and an energy density of 21.1 Wh kg⁻¹ at a current density of 0.6 mA cm⁻². The RGO sheets served as conductor and framework under the PPy layer, which could facilitate electron transfer between RGO and PPy and restrict the swelling and shrinking of PPy, thus resulting in improved electrochemical properties respect to the PPy-fabric device.     

Will smartwatches last? factors contributing to intention to keep using smart wearable technology

This study aims to deepen our understanding of the underlying factors affecting the intention to continue using increasingly popular wearable technology. A new theoretical model is developed and validated to extend traditional technology acceptance theories by identifying several value drivers of the continuous intention and actual usage of wearable devices. Hypotheses were tested using partial least squares path modeling on data collected from 383 actual smartwatch users. The results provide wearable device manufacturers with practical guidance for optimizing competition strategies. They also offer policy-making insights for practitioners to promote better wearable devices on the market, especially during the early stages of adoption.     

A Highly Flexible and Lightweight MnO2/Graphene Membrane for Superior Zinc-Ion Batteries

Batteries powering next-generation flexible and wearable electronic devices require superior mechanical bendability and foldability. Herein, a self-standing hybrid nanoarchitecture constructed by ultralong MnO₂ nanowires and graphene nanosheets as an advanced and lightweight cathodes for flexible and foldable zinc-ion batteries (ZIBs) is designed and fabricated. The new-designed batteries exhibit not only a high energy density of 436 Wh kg⁻¹ based on the total cathode mass but also good 2000-cycling durability. More importantly, the shape-deformable ZIBs can be operated without any capacity loss under both bent and folded circumstances. The foldable ZIBs with high energy density and long lifetime hold great promise for smart and wearable electronics.