Textiles have been concomitant of human civilization for thousands of years. With the advances in chemistry and materials, integrating textiles with energy harvesters will provide a sustainable, environmentally friendly, pervasive, and wearable energy solution for distributed on-body electronics in the era of Internet of Things. This article comprehensively and thoughtfully reviews research activities regarding the utilization of smart textiles for harvesting energy from renewable energy sources on the human body and its surroundings. Specifically, we start with a brief introduction to contextualize the significance of smart textiles in light of the emerging energy crisis, environmental pollution, and public health. Next, we systematically review smart textiles according to their abilities to harvest biomechanical energy, body heat energy, biochemical energy, solar energy as well as hybrid forms of energy. Finally, we provide a critical analysis of smart textiles and insights into remaining challenges and future directions. With worldwide efforts, innovations in chemistry and materials elaborated in this review will push forward the frontiers of smart textiles, which will soon revolutionize our lives in the era of Internet of Things.

Smart Textiles for Electricity Generation.

The increasing demand for wearable electronics and the intensification of electromagnetic pollution have boosted the exploration of high-performance flexible microwave absorption (MA) materials Herein, the hierarchical Ti3C2Tx MXene/Ni chain/ZnO array hybrid nanostructures are rationally constructed on cotton fabric for acquiring enhanced MA performance and durable self-cleaning ability Based on the high dielectric loss capacity of MXenes and ZnO arrays, by controlling dip-coating numbers of Ni chains, the magnetic loss can be manipulated to modulate the impedance matching, reflection loss (RL), and effective absorption bandwidth (EAB, the bandwidth of RL < -10 dB) The minimum RL value of the designed fabric can reach -351 dB at 83 GHz with a thickness of 28 mm, and its EAB can cover the whole X-band with only a 22 mm thickness In addition, the designed fabric also exhibits superior liquid repellency and durable self-cleaning ability due to the combination of the hybrid nanostructures and a superhydrophobic coating This work provides an insight for rational design of textile-based MA materials, showing potential applications in flexible and wearable functional electronics

Hierarchical Ti3C2Tx MXene/Ni Chain/ZnO Array Hybrid Nanostructures on Cotton Fabric for Durable Self-Cleaning and Enhanced Microwave Absorption.

DOI: 10.1002/aenm.201903921 us warm in cold climates and shielded us from the nakedness for modesty and civilization.[1,2] Cloth is also a platform for artists, designers, and tailors to advance the clothing demands with emerging materials, process, and fashion.[2] While the majority of the functionalities of clothes lie in their physical attributes, such as their softness, breathability, air/ vapor permeability, and, of course the appearance, their role in thermal management is equally, if not more, important. The primary goal of clothing is to satisfy human being’s basic needs in thermal comfort, by providing cooling in the hot environment or heating in the cold environment.[1] The energy management aspect of clothing is becoming an increasingly important and attractive aspect due to our increasing awareness to energy consumption and our persisting pursuit of comfort and health. The finite availability and the associated environmental consequence of fossil fuels have motivated us to save energy from virtually all aspects of our daily lives. A suitable thermal envelop is a necessity for our living and working. To create a comfortable indoor environment, the building heating, ventilation, and air conditioning (HVAC) systems are widely used for space cooling and heating at the expense of excessive energy consumption.[3–6] According to United States In this decade, the demands of energy saving and diverse personal thermoregulation requirements along with the emergence of wearable electronics and smart textiles give rise to the resurgence of personal thermal management (PTM) technologies. PTM, including personal cooling, heating, insulation, and thermoregulation, are far more flexible and extensive than the traditional air/liquid cooling garments for the human body. Concomitantly, many new advanced materials and strategies have emerged in this decade, promoting the thermoregulation performance and the wearing comfort of PTM simultaneously. In this review, an overview is presented of the state-ofthe-art and the prospects in this burgeoning field. The emerging materials and strategies of PTM are introduced, and classed by their thermal functions. The concept of infrared-transparent visible-opaque fabric (ITVOF) is first highlighted, as it triggers the work on advanced PTM by combining it with radiative cooling, and the corresponding implementations and realizations are subsequently introduced, followed by wearable heaters, flexible thermoelectric devices, and sweat-management Janus textiles. Finally, critical considerations on the challenges and opportunities of PTM are presented and future directions are identified, including thermally conductive polymers and fibers, physiological/psychological statistical analysis, and smart PTM strategies.

Emerging Materials and Strategies for Personal Thermal Management

Artificial intelligence (AI) is one of the most disruptive technologies of our time. Interest in the use of AI for urban innovation continues to grow. Particularly, the rise of smart cities—urban locations that are enabled by community, technology, and policy to deliver productivity, innovation, livability, wellbeing, sustainability, accessibility, good governance, and good planning—has increased the demand for AI-enabled innovations. There is, nevertheless, no scholarly work that provides a comprehensive review on the topic. This paper generates insights into how AI can contribute to the development of smarter cities. A systematic review of the literature is selected as the methodologic approach. Results are categorized under the main smart city development dimensions, i.e., economy, society, environment, and governance. The findings of the systematic review containing 93 articles disclose that: (a) AI in the context of smart cities is an emerging field of research and practice. (b) The central focus of the literature is on AI technologies, algorithms, and their current and prospective applications. (c) AI applications in the context of smart cities mainly concentrate on business efficiency, data analytics, education, energy, environmental sustainability, health, land use, security, transport, and urban management areas. (d) There is limited scholarly research investigating the risks of wider AI utilization. (e) Upcoming disruptions of AI in cities and societies have not been adequately examined. Current and potential contributions of AI to the development of smarter cities are outlined in this paper to inform scholars of prospective areas for further research.

https://www.mdpi.com/1996-1073/13/6/1473/pdf

Contributions and risks of artificial intelligence (AI) in building smarter cities: Insights from a systematic review of the literature

Although flexible and multifunctional textile-based electronics are promising for wearable devices, it is still a challenge to seamlessly integrate excellent conductivity into textiles without sacrificing their intrinsic flexibility and breathability. Herein, the vertically interconnected conductive networks are constructed based on a meshy template of weave cotton fabrics with interwoven warp and weft yarns. The two-dimensional early transition metal carbides/nitrides (MXenes), with unique metallic conductivity and hydrophilic surfaces, are uniformly and intimately attached to the preformed fabric via a spray-drying coating approach. Through adjusting the spray-drying cycles, the degree of conductive interconnectivity for the fabrics is precisely tuned, thereby affording highly conductive and breathable fabrics with integrated Joule heating, electromagnetic interference (EMI) shielding and strain sensing performances. Interestingly, triggered by the interwoven conductive architecture, the MXene-decorated fabrics with a low loading of 6 wt % (0.78 mg cm-2) offer an outstanding electrical conductivity of 5 Ω sq-1. The promising electrical conductivity further endows the fabrics with superior Joule heating performance with a heating temperature up to 150 °C at a supply voltage of 6 V, excellent EMI shielding performance, and highly sensitive strain responses to human motion. Consequently, this work offers a novel strategy for the versatile design of multifunctional textile-based wearable devices.

Flexible MXene-Decorated Fabric with Interwoven Conductive Networks for Integrated Joule Heating, Electromagnetic Interference Shielding, and Strain Sensing Performances.

The programmable nature of smart textiles makes them an indispensable part of an emerging new technology field. Smart textile-integrated microelectronic systems (STIMES), which combine microelectronics and technology such as artificial intelligence and augmented or virtual reality, have been intensively explored. A vast range of research activities have been reported. Many promising applications in healthcare, the internet of things (IoT), smart city management, robotics, etc., have been demonstrated around the world. A timely overview and comprehensive review of progress of this field in the last five years are provided. Several main aspects are covered: functional materials, major fabrication processes of smart textile components, functional devices, system architectures and heterogeneous integration, wearable applications in human and nonhuman-related areas, and the safety and security of STIMES. The major types of textile-integrated nonconventional functional devices are discussed in detail: sensors, actuators, displays, antennas, energy harvesters and their hybrids, batteries and supercapacitors, circuit boards, and memory devices.

Smart Textile-Integrated Microelectronic Systems for Wearable Applications

High-Temperature-Tolerant Artificial Muscles Using Poly(p-phenylene benzobisoxazole) Composite Yarns

Integrating sense in a thin artificial muscle fiber for environmental adaption and actuation path tracing, as a snail tentacle does, is highly needed but still challenging because of the interfacing mismatch between the fiber’s actuation and sensing components. Here, we report an artificial neuromuscular fiber by wrapping a carbon nanotube (CNT) fiber core in sequence with an elastomer layer, a nanofiber network, and an MXene/CNT thin sheath, achieving the ingenious sense-judge-act intelligent system in an elastic fiber. The CNT/elastomer components provide actuation, and the sheath enables touch/stretch perception and hysteresis-free cyclic actuation tracing due to its strain-dependent resistance. As a whole, the coaxial structure builds a dielectric capacitor that enables sensitive touchless perception. The key to seamless integration is to use a nanofiber interface that allows the sensing layer to adaptively trace but not restrict actuation. This work provides promising solutions for closed-loop control for future intelligent soft robots.

https://www.science.org/doi/pdf/10.1126/sciadv.abq7703?download=true

Artificial neuromuscular fibers by multilayered coaxial integration with dynamic adaption

Artificial muscle fascicles integrated with high-performance actuation properties and energy-storage function

Present artificial muscles have been suffering from poor actuation step precision and the need of energy input to maintain actuated states due to weak interactions between guest and host materials or the unstable structural changes. Herein, these challenges are addressed by deploying a mechanism of reversible faradaic insertion and extraction reactions between tetrachloroaluminate ions and collapsed carbon nanotubes. This mechanism allows tetrachloroaluminate ions as a strong but dynamic "locker" to achieve an energy-free high-tension catch state and programmable stepwise actuation in the yarn muscle. When powered off, the muscle nearly 100% maintained any achieved contractile strokes even under loads up to 96,000 times the muscle weight. The actuation mechanism allowed the programmable control of stroke steps down to 1% during reversible actuation. The isometric stress generated by the yarn muscle (14.6 MPa in maximum, 40 times that of skeletal muscles) was also energy freely lockable and step controllable with high precision. Importantly, when fully charged, the muscle stored energy with a high capacity of 102 mAh g-1, allowing the muscle as a battery to power secondary muscles or other devices.

Ming Ren

Papers

Smart Textile-Integrated Microelectronic Systems for Wearable Applications

High-Temperature-Tolerant Artificial Muscles Using Poly(p-phenylene benzobisoxazole) Composite Yarns

Artificial neuromuscular fibers by multilayered coaxial integration with dynamic adaption

Artificial muscle fascicles integrated with high-performance actuation properties and energy-storage function

Stepwise Artificial Yarn Muscles with Energy-Free Catch States Driven by Aluminum-Ion Insertion.