High-Performance Laminated Fabric with Enhanced Photothermal Conversion and Joule Heating Effect for Personal Thermal Management

Directional fabrication of an ultra-light and porous bacterial nanocellulose/MXene composite aerogel for efficient thermal management

Global warming has intensified extreme weather events, necessitating advanced thermal management systems to protect human health. Due to its unique properties of increasing phonon scattering at interlayer interfaces and wide spectral absorption, MXene has great potential in thermal management. However, the self-stacking tendency of MXene caused by hydrogen bonding and van der Waals force limits its further application. Herein, we have successfully fabricated an ultra-light (0.011 g cm-3) three-dimensional (3D) bacterial nanocellulose (BNC)/MXene aerogel (BM) through directional freezing. The BNC serves as scaffolds, offering a porous structure with ultra-low thermal conductivity (0.038 W m-1 K-1), high porosity (99.33 %), and excellent insulation (ΔT of 164 at 200 °C). Additionally, the BM aerogel shows remarkable photo-thermal conversion efficiency (98 % solar absorption, 0.25-2.5 μm), quick thermal response (88 °C in 10 s), and thermal stability (89 °C sustained after 120 min). These multifunctional properties make the BM aerogel a potential candidate for advanced thermal management in response to global climate challenges.

Knitting-stitching bifacial metafabrics with switchable thermal and moisture transmissibility for multimodal dynamic personal thermoregulation

Smart textiles with thermal and moisture management functionalities are highly desirable for enhancing human comfort and reducing weather-related health issues. However, achieving high-performance thermoregulatory fabrics that simultaneously exhibit reversible cooling and heating functions, and effective sweat management through industrial fabrication, remains challenging due to the lack of compatible textile technologies capable of manipulating hierarchical structures. Herein, a robust thermal and moisture-managing metafabric (TMM fabric) with a stitching-interlaced-knit structure is developed using industrialized machine knit technology. Unlike layered fabrics, this knitted structure endows the TMM fabric with different appearances on its two opposite surfaces for reversible photon management, while integrating these surfaces into an all-in-one construction using interlacing yarns. The interlacing yarns also serve as pathways for heat and moisture transmission, enhancing thermal conduction and water transportation. A coupling agent-assisted zinc oxide nanoprocessing is further applied to the cooling surface of the TMM fabric to improve solar reflectivity. The bifacial TMM fabric demonstrates on-demand radiative/evaporation cooling and photo-thermal heating capacities by simply flipping the fabric, achieving an effective temperature regulation of over 17 °C. Furthermore, the TMM fabric shows desirable electro-thermal performance, enabling it to protect the human body from harsh low-temperature conditions of -18 °C. Moreover, the TMM fabric demonstrates good breathability and robust mechanical properties. This facile structural design as a paradigm provides a new insight for producing scalable, robust and efficient personal thermoregulation textiles adaptive to superwide temperature changes using well-engineered textile structures.

Advanced Thermoactive Nanomaterials for Thermomedical Tissue Regeneration: Opportunities and Challenges

Nanomaterials usually possess remarkable properties, including excellent biocompatibility, unique physical and chemical characteristics, and bionic attributes, which make them highly promising for applications in tissue regeneration. Thermal therapy has emerged as a versatile approach for wound healing, nerve repair, bone regeneration, tumor therapy, and antibacterial tissue regeneration. By combining nanomaterials with thermal therapy, multifunctional nanomaterials with thermogenic effects and tissue regeneration capabilities can be engineered to achieve enhanced therapeutic outcomes. This study provides a comprehensive review of the effects of thermal stimulation on cellular and tissue regeneration. Furthermore, it highlights the applications of photothermal, magnetothermal, and electrothermal nanomaterials, and thermally responsive drug delivery systems in tissue engineering. In Addition, the bioactivities and biocompatibilities of several representative thermal nanomaterials are discussed. Finally, the challenges facing thermal nanomaterials are outlined, and future prospects in the field are presented with the aim of offering new opportunities and avenues for the utilization of thermal nanomaterials in tissue regeneration.

New Carbon Materials for Multifunctional Soft Electronics

Soft electronics are garnering significant attention due to their wide-ranging applications in artificial skin, health monitoring, human-machine interaction, artificial intelligence, and the Internet of Things. Various soft physical sensors such as mechanical sensors, temperature sensors, and humidity sensors are the fundamental building blocks for soft electronics. While the fast growth and widespread utilization of electronic devices have elevated life quality, the consequential electromagnetic interference (EMI) and radiation pose potential threats to device precision and human health. Another substantial concern pertains to overheating issues that occur during prolonged operation. Therefore, the design of multifunctional soft electronics exhibiting excellent capabilities in sensing, EMI shielding, and thermal management is of paramount importance. Because of the prominent advantages in chemical stability, electrical and thermal conductivity, and easy functionalization, new carbon materials including carbon nanotubes, graphene and its derivatives, graphdiyne, and sustainable natural-biomass-derived carbon are particularly promising candidates for multifunctional soft electronics. This review summarizes the latest advancements in multifunctional soft electronics based on new carbon materials across a range of performance aspects, mainly focusing on the structure or composite design, and fabrication method on the physical signals monitoring, EMI shielding, and thermal management. Furthermore, the device integration strategies and corresponding intriguing applications are highlighted. Finally, this review presents prospects aimed at overcoming current barriers and advancing the development of state-of-the-art multifunctional soft electronics.

Release and Transport of Nanomaterials from Hydrogels Controlled by Temperature

Understanding the transport of nanoparticles from and within hydrogels is a key issue for the design of nanocomposite hydrogels for drug delivery systems and tissue engineering. To investigate the translocation of nanocarriers from and within hydrogel networks triggered by changes of temperature, ultrasmall (8 nm) and small (80 nm) silica nanocapsules are embedded in temperature-responsive hydrogels and non-responsive hydrogels. The ultrasmall silica nanocapsules are released from temperature-responsive hydrogels to water or transported to other hydrogels upon direct activation by heating or indirect activation by Joule heating; while, they are not released from non-responsive hydrogel. Programmable transport of nanocarriers from and in hydrogels provides insights for the development of complex biomedical devices and soft robotics.

Universal salt-assisted assembly of MXene from suspension on polymer substrates

Two-dimensional carbides and nitrides, known as MXenes, are promising for water-processable coatings due to their excellent electrical, thermal, and optical properties. However, depositing hydrophilic MXene nanosheets onto inert or hydrophobic polymer surfaces requires plasma treatment or chemical modification. This study demonstrates a universal salt-assisted assembly method that produces ultra-thin, uniform MXene coatings with exceptional mechanical stability and washability on various polymers, including high-performance polymers for extreme temperatures. The salt in the Ti3C2Tx colloidal suspension reduces surface charges, enabling electrostatically hydrophobized MXene deposition on polymers. A library of salts was used to optimize assembly kinetics and coating morphology. A 170 nm MXene coating can reduce radiation temperature by ~200 °C on a 300 °C PEEK substrate, while the coating on Kevlar fabric provides comfort in extreme conditions, including outer space and polar regions.

1-Tetradecanol phase change material microcapsules coating on cotton fabric for enhanced thermoregulation

Rising climate change and extreme weather conditions underpin thermoregulation limitations of conventional textiles. This study investigates enhancing the thermal properties of cotton fabric by incorporating synthesized 1-tetradecanol (TD) phase change material (PCM) microcapsules. Characterization of the TD microcapsules was performed using dynamic light scattering (DLS), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The microcapsules (average size of 0.49 μm) displayed a melting enthalpy (∆Hm) of 105 J·g-1 and a crystallization enthalpy (∆Hc) of 51 J·g-1. The microcapsules were mixed with the acrylic binder in three different ratios (75:25, 50:50, and 25:75). Hydrothermal, knife-over-roll, and pad-dry-cure methods were employed for coating microcapsules to cotton fabric. Microcapsule coating on cotton fabric using hydrothermal coating with a 75:25 microcapsule binder ratio achieved the highest add-on (55 %) and good durability after 25 home washes. The thermal insulation R-value of the coated fabric was enhanced (0.0029 m2 K·W-1) at 40 °C. The real-time test showed a temperature difference of 2.8 °C and thermal imaging displayed lower emissivity for TD-coated fabric. The TD microcapsule coating offers a promising method for developing climate-responsive textiles, enhancing thermal comfort, and reducing energy consumption in heating and cooling systems.

Superhydrophobic Solar-to-Thermal Materials Toward Cutting-Edge Applications

Solar-to-thermal conversion is a direct and effective way to absorb sunlight for heat via the rational design and control of photothermal materials. However, when exposed to water-existed conditions, the conventional solar-to-thermal performance may experience severe degradation owing to the high specific heat capacity of water. To tackle with the challenge, the water-repellent function is introduced to construct superhydrophobic solar-to-thermal materials (SSTMs) for achieving stable heating, and even, for creating new application possibilities under water droplets, sweat, seawater, and ice environments. An in-depth review of cutting-edge research of SSTMs is given, focusing on synergetic functions, typical construction methods, and cutting-edge potentials based on water medium. Moreover, the current challenges and future prospects based on SSTMs are also carefully discussed.

Wearable Aerogels for Personal Thermal Management and Smart Devices

Extreme climates have become frequent nowadays, causing increased heat stress in human daily life. Personal thermal management (PTM), a technology that controls the human body's microenvironment, has become a promising strategy to address heat stress. While effective in ordinary environments, traditional high-performance fibers, such as ultrafine, porous, highly thermally conductive, and phase change materials, fall short when dealing with harsh conditions or large temperature fluctuations. Aerogels, a third-generation superinsulation material, have garnered extensive attention among researchers for their thermal management applications in building energy conservation, transportation, and aerospace, attributed to their extremely low densities and thermal conductivity. While aerogels have historically faced challenges related to weak mechanical strength and limited secondary processing capacity, recent advancements have witnessed notable progress in the development of wearable aerogels for PTM. This progress underscores their potential applications within extremely harsh environments, serving as self-powered smart devices and sensors. This Review offers a timely overview of wearable aerogels and their PTM applications with a particular focus on their wearability and suitability. Finally, the discussion classifies five types of PTM applications based on aerogel function: thermal insulation, heating, cooling, adaptive regulation (involving thermal insulation, heating, and cooling), and utilization of aerogels as wearable smart devices.

Advances in Printed Electronic Textiles

Electronic textiles (e-textiles) have emerged as a revolutionary solution for personalized healthcare, enabling the continuous collection and communication of diverse physiological parameters when seamlessly integrated with the human body. Among various methods employed to create wearable e-textiles, printing offers unparalleled flexibility and comfort, seamlessly integrating wearables into garments. This has spurred growing research interest in printed e-textiles, due to their vast design versatility, material options, fabrication techniques, and wide-ranging applications. Here, a comprehensive overview of the crucial considerations in fabricating printed e-textiles is provided, encompassing the selection of conductive materials and substrates, as well as the essential pre- and post-treatments involved. Furthermore, the diverse printing techniques and the specific requirements are discussed, highlighting the advantages and limitations of each method. Additionally, the multitude of wearable applications made possible by printed e-textiles is explored, such as their integration as various sensors, supercapacitors, and heated garments. Finally, a forward-looking perspective is provided, discussing future prospects and emerging trends in the realm of printed wearable e-textiles. As advancements in materials science, printing technologies, and design innovation continue to unfold, the transformative potential of printed e-textiles in healthcare and beyond is poised to revolutionize the way wearable technology interacts and benefits.

Silver nanowire-infused carbon aerogel: A multifunctional nanocellulose-derived material for personal thermal management

Personal thermal management (PTM) textiles for outdoor activities have become increasingly important for addressing energy consumption and thermal comfortable. Cellulose nanofiber (CNF) aerogels have emerged as promising candidates for PTM due to the eco-friendliness, lightweight, and low thermal conductivity. However, the singular insulation capability may not be sufficient to accommodate the diverse and harsh outdoor conditions. Herein, we carbonized CNF-based aerogel to fabricate anisotropic carbon aerogels, and then incorporated silver nanowires (AgNWs) upon onside to fabricate the dual-function AgNWs/carbon aerogel. The resulting material inherits high porosity (99.3 %), high surface area (503.2 m2/g), low density (7.08 mg/cm3), and low thermal conductivity (18.2 mW·m-1·k-1 in the axial direction) to act as an ideal thermal insulator. The AgNWs coating side demonstrates low IR-emissivity (17.6 % at 7-14 μm) and the carbon aerogel side has high solar absorptivity (91.97 %). Moreover, the AgNWs/carbon aerogel shows Joule heating performance (∆T = 44.5 °C within 3 min at 5 V). The multi-heating modes enabling self-adaptable thermal comfortable under various harsh environment. Additionally, the material's breathability, permeability, and electromagnetic shielding characteristics also make it suitable candidate for advanced wearable textiles for PTM.

Chitosan/copper sulfide nanoparticles (CS/CuSNPs) hybrid fibers with improved mechanical and photo-thermal conversion properties via tuning CuSNPs' morphological structures

Conventional textiles are inadequate for maintaining warmth in extremely cold conditions. Therefore, the development of photo-thermal fibers for personal thermal management textiles has emerged as an urgent need. Herein, novel chitosan/copper sulfide nanoparticles (CS/CuSNPs) hybrid fibers with photo-thermal function were fabricated successfully. Significantly, our study demonstrated that the tensile and photo-thermal conversation properties of the CS/CuSNPs hybrid fibers could be effectively regulated by altering the CuSNPs` morphological structures. Compared with other CuSNPs (tube-like, sphere-like, and flower-like), the plate-like CuSNPs with smooth surfaces and uniform nanometer size played a significant role by scattering incident light in the fibers as a secondary light source for CuSNPs absorbance. Thus, under IR light irradiation at a power density of 1.0 W/cm2, the surface temperature of CS/0.1 wt% plate-like CuSNPs hybrid fibers sharply increased by 27.6 °C, which was more than 4 times of the pure CS fibers. And the breaking strength and initial modulus of CS/0.1 wt% plate-like CuSNPs hybrid fibers increased by more than 18.37 and 6.88 % compared with the nascent CS fibers. This study develops a novel and effective strategy to tune the photo-thermal and tensile properties of CS hybrid fibers without incorporating more content or additives.

The Photothermal Conversion and UV Resistance of Silk Fabrics Being Achieved through Surface Modification with C@SiO2 Nanoparticles

With the improvement in people's living standards, the development and application of smart textiles are receiving increasing attention. In this study, a carbon nanosurface was successfully coated with a SiO2 layer to form C@SiO2 nanomaterials, which improved the dispersion of carbon nanomaterials in an aqueous solution and enhanced the absorption of light by the carbon nanoparticles. C@SiO2 nanoparticles were coupled on the surface of silk fabric with the silane coupling agent KH570 to form C@SiO2 nanosilk fabric. The silk fabric that was subjected to such surface modification was endowed with a special photothermal function. The results obtained with scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and infrared spectroscopy (FTIR) showed that C@SiO2 nanoparticles were successfully modified on the surface of the silk fabric. In addition, under the irradiation of near-infrared light with a power of 20 W and a wavelength of 808 nm, the C@SiO2 nanosilk fabric experienced rapid warming from 23 °C to 60 °C within 30 s. After subjecting the functional fabric to hundreds of photothermal experiments and multiple washes, the photothermal efficiency remained largely unchanged and proved to be durable and stable. In addition, the thermogravimetric (TG) analysis results showed that the C@SiO2 nanoparticles contributed to the thermal stability of the silk fabric. The UV transmittance results indicated that C@SiO2 nanofabric is UV-resistant. The silk modification method developed in this study is low-cost, efficient, and environmentally friendly. It has some prospects for future applications in the textile industry.

Ag Nanoparticles-Coated Shish-Kebab Superstructure Film for Wearable Heater

Passive and active wearable heaters have received widespread attention due to their efficient utilization of solar energy and all-weather heating capabilities, but the current challenges are their preparation processes being time-consuming and equipment expensive. Herein, a simple and facilitated preparation method for the multifunctional wearable heater was developed, which springs Ag nanoparticles on the shish-kebab superstructure film via deposited melanin-like polydopamine as the adhesive. The light absorption ability of the resultant wearable heater in the visible region can be significantly enhanced by the addition of polydopamine, realizing a highly efficient photothermal conversion ability. Accordingly, it can achieve rapid warming ability whether passive heating (up to 45 °C about 60 s at 100 mW/cm2) or active heating (up to 72 °C about 40 s at 0.6 V), compared to ordinary cotton fabric. In addition, it can realize a 6.3 °C temperature difference with Cotton, showing excellent heat preservation ability. This study demonstrates a simple and low-cost approach for the prepared shish-kebab superstructure-based wearable heaters.

Toward low-emissivity passive heating: a supramolecular-enhanced membrane with warmth retention

Maintaining a reasonably stable body temperature is vital for a variety of human activities in an energy-conservation strategy. However, it is well-known that metal-like materials, utilized as radiative reflectors, severely restrict wearability properties, thus posing a tremendous obstacle in personal thermal management (PTM) systems. Herein, we designed a supramolecular-enhanced membrane (SupraEM) acting as a mid-infrared (MIR) reflector to solve the conundrum of warmth-wearability performance. Benefiting from the low-emissivity of decorating titanium carbide (MXene) and the formation of supramolecular interactions, the prototyped polyvinylidene difluoride&Polyurethane/MXene (PVDF&PU/MXene) SupraEM demonstrated a low-emissivity of 0.246 and reinforced mechanical performance, resulting in an evenly higher temperature retention of 8 °C in comparison to the pristine hybrid membrane counterpart, and compared with a commercial textile that is three times thicker, it also exhibited higher temperature retention of 6.2 °C. This work demonstrates the wearability of decorated MXene without sacrificing its temperature retention, overcoming a major bottleneck that has plagued MXene as a thermoregulatory material for PTM systems.

Ti3C2Tx MXene and cellulose-based aerogel phase change composite decorated laminated fabric with excellent electro/solar-thermal conversion and high latent heat

Wearable heaters have attracted growing attention for maintaining a relatively constant temperature of the human body in cold environments with near zero energy consumption. Herein, we developed a multifunctional laminated fabric with fascinating electro/solar-thermal conversion, thermal energy storage and thermal insulation properties. With cotton fabric as the substrate, MXene/polydimethylsiloxane (PDMS) conductive network was decorated on the upper layer, and carbon nanotube (CNT)/cellulose nanofiber (CNF)/paraffin (PA) aerogel phase change composites were assembled on the bottom layer. Attributed to the strong conductivity and light absorption of MXene and the light/thermal response of CNT and PA components, this wearable laminated fabric broke the limitation of intermittent solar photothermal heating, and integrated multiple heating modes to precisely heat the human body. Meanwhile, the low thermal conductivity of aerogel retarded heat loss. The laminated fabric can help people better adapt to a variety of complex and changeable environments such as cold winter, rainy days and nights. This study provides a promising and energy-efficient avenue for the development of all-day personal thermal management fabrics.

Waterproof, Light Responsive, and Highly Sensitive Fabric Strain Sensor for Flexible Electronics

Corrosion resistant, durable, and lightweight flexible strain sensor with multiple functionalities is an urgent demand for modern flexible wearable devices. However, currently developed wearable devices are still limited by poor environmental adaptability and functional singleness. In this work, a conductive fabric with multifunctionality in addition to sensing was successfully prepared by assembling zero dimensional silver nanoparticles (AgNPs) and one-dimensional carbon nanotubes (CNTs) layer by layer on the surface of the elastic polypropylene nonwoven fabric (named PACS fabric). Polystyrene-block-poly(ethylene-co-butylene)-block-polystyrene (SEBS) added as binder materials favored strong interaction between conductive fillers and the fabric. Benefiting from the synergistic interaction among the conductive fillers with different dimensions and the fabric, the strain sensor based on the conductive fabric showed high sensitivity (GF up to 8064), wide detection range (0-200%), and excellent stability and durability (more than 10000 stretch-release cycles). Besides, the prepared conductive fabric showed superhydrophobicity (water contact angle = 154°) with excellent durability. This ensured the performance stability of the fabric sensor in harsh environments. At the same time, the fabric also showed excellent photothermal conversion performance (90 °C at a power density of 0.2 W/cm2 within 20 s). The PACS fabric strain sensor proved excellent performance and environmental adaptability, revealing great potential to be applied in human motion monitoring, self-cleaning, biomedicine, and other fields.

Asymmetric Multienergy-Coupled Radiative Warming Textiles for Personal Thermal-Moisture Management

In order to address the requirements for warmth and energy conservation in cold climates, the development of personal thermal management textiles that regulate local human thermal comfort has emerged as a promising solution in recent times. Nevertheless, existing warming textile strategies often rely on a singular energy source, exhibit inadequate air/moisture permeability, and lack adaptability to dynamic and intricate climate variations. Herein, a novel multienergy-coupled radiative warming Janus textile has been effectively designed and fabricated via screen printing and foam finishing. Taking advantage of the synergistic effects of directional water transport capability of polyester-covered cotton (with a directional water-transport index of R = 577.5%), high mid-infrared radiant reflection (at 60%), electrothermal conversion of copper coating (with a sheet resistance of 0.01 Ω sq-1), and strong solar absorption of the nanoporous structure TA@APTES@Fe(III)@CNT (TAFC) coating (at 98.5%), the Janus fabric exhibits exceptional performance in expelling out one-way sweat/moisture (R = 329.3%) and solar heating (86.9 °C)/Joule heating (226.4 °C at 3.0 V)/heat retention (2.4 °C higher than that of cotton fabric). Furthermore, the fabric is also provided with exceptional mechanical, washing, flame-retardant, and antibacterial performance. This research holds the potential to revolutionize the development and production of warming textiles by incorporating desirable sweat/moisture permeability and multienergy-coupled heating.

Regulating Al2O3/PAN/PEG Nanofiber Membranes with Suitable Phase Change Thermoregulation Features

To address the thermal comfort needs of the human body, the development of personal thermal management textile is critical. Phase change materials (PCMs) have a wide range of applications in thermal management due to their large thermal storage capacity and their isothermal properties during phase change. However, their inherent low thermal conductivity and susceptibility to leakage severely limit their application range. In this study, polyethylene glycol (PEG) was used as the PCM and polyacrylonitrile (PAN) as the polymer backbone, and the thermal conductivity was increased by adding spherical nano-alumina (Al2O3). Utilizing coaxial electrospinning technology, phase-change thermoregulated nanofiber membranes with a core-shell structure were created. The study demonstrates that the membranes perform best in terms of thermal responsiveness and thermoregulation when 5% Al2O3 is added. The prepared nanofiber membranes have a melting enthalpy of 60.05 J·g-1 and retain a high enthalpy after 50 cycles of cold and heat, thus withstanding sudden changes in ambient temperature well. Additionally, the nanofiber membranes have excellent air permeability and high moisture permeability, which can increase wearer comfort. As a result, the constructed coaxial phase change thermoregulated nanofiber membranes can be used as a promising textile for personal thermal management.

Antibacterial Superhydrophobic Cotton Fabric with Photothermal, Self-Cleaning, and Ultraviolet Protection Functionalities

Cotton fabrics with superhydrophobic, antibacterial, UV protection, and photothermal properties were developed using Ag/PDMS coatings, and the role of coating formulations on the obtained functionalities was studied. Specific attention was paid to understanding the relationships between the fabrics' superhydrophobicity and antibacterial activity against Escherichia coli (E. coli) bacteria. UV protection performance of Ag/PDMS coatings was thoroughly evaluated based on the variation of UV transmission rate through coated fabrics and photoinduced chemiluminescence spectra. Moreover, the effect of silver nanoparticles (Ag NPs) and PDMS on developing a photothermal effect on fabrics was discussed. It was found that the content of Ag NPs and PDMS played critical roles in determining the water contact angle (WCA) on modified fabrics. The largest WCA was 171.31°, which was durable even after numerous accelerated wash cycles and abrasions. Antibacterial activity of fabrics showed the positive effect of pure PDMS in bacterial growth inhibition. Moreover, it was found that the antibacterial performance was greatly affected by the content of Ag NPs loaded on fabrics rather than their superhydrophobic status. Moreover, increasing the content of Ag NPs boosted the UV protection level of fabrics, improved fabrics photostability, and reduced the UV transmission rate through fabrics. Testing the photothermal effect confirmed that the content of Ag NPs and PDMS both played prominent roles, where Ag acted as a photothermal agent and PDMS determined the NIR reflection rate from the coated surface. The modified fabrics were characterized using TGA, SEM, FTIR, and XRD techniques, and it was confirmed that using a higher amount of PDMS increased the amount of Ag NPs deposition on fabrics.

Dual-asymmetrically selective interfaces-enhanced poly(lactic acid)-based nanofabric with sweat management and switchable radiative cooling and thermal insulation

All-weather personal thermal regulation has far been challenged by variable environments especially the regulatory failure caused by highly-dense solar radiation, low environmental radiation and the fluctuated epidermal moisture in different seasons. Herein, from the design of interface selectivity, dual-asymmetrically optical and wetting selective polylactic acid-based (PLA) Janus-type nanofabric is proposed to achieve on-demand radiative cooling and heating as well as sweat transportation. Hollow TiO₂ particles are introduced in PLA nanofabric causing high interface scattering (∼99%) and infrared emission (∼91.2%) as well as surface hydrophobicity (CA > 140°). The strictly optical and wetting selectivity help achieve ∼12.8℃ of net cooling effect under > 1500 W/m² of solar power and ∼5℃ of cooling advantage higher than cotton fabric and sweat resistance simultaneously. Contrarily, the semi-embedded Ag nanowires (AgNWs) with high conductivity (0.245 Ω/sq) endows the nanofabric with visible water permeability and excellent interface reflection for thermal radiation from body (>65%) thus causing ∼7℃ of thermal shielding. Through simple interface flipping, synergistical cooling-sweat reducing and warming-sweat resisting can be achieved to satisfy the thermal regulation in all weather. Compared with conventional fabrics, multi-functional Janus-type passive personal thermal management nanofabrics would be of great significance to achieve the personal health maintenance and energy sustainability.

Asymmetrical Emissivity and Wettability in Stitching Treble Weave Metafabric for Synchronous Personal Thermal-Moisture Management

Developing textiles with passive thermal management is an effective strategy to maintain the human body healthy as well as decrease energy consumption. Personal thermal management (PTM) textiles with engineered constituent element and fabric structure have been developed, however the comfortability and robustness of these textiles remains a challenge due to the complexity of passive thermal-moisture management. Here a metafabric with asymmetrical stitching treble weave based on woven structure design and yarn functionalization is developed, in which the thermal radiation regulation and moisture-wicking can be achieved simultaneously throughout the dual-mode metafabric due to its optically regulated property, multi-branched through-porous structure and surface wetting difference. With simply flipping, the metafabric enables high solar reflectivity (87.6%) and IR emissivity (94%) in the cooling mode, and a low IR emissivity of 41.3% in the heating mode. When overheating and sweating, the cooling capacity reaches to ≈9 °C owing to the synergistic effect of radiation and evaporation. Moreover, the tensile strengths of the metafabric are 46.18 MPa (warp direction) and 37.59 MPa (weft direction), respectively. This work provides a facile strategy to fabricate multi-functional integrated metafabrics with much flexibility and thus has great potential for thermal management applications and sustainable energy.

MXene-Decorated Smart Textiles with the Desired Mid-Infrared Emissivity for Passive Personal Thermal Management

Multifunctional and long-term stable wearable heating systems have attracted extensive attention from experts, yet smart textiles that only rely on harvesting the body's heat without additional energy still face huge challenges in practical applications. Herein, we rationally prepared the monolayer MXene Ti₃C₂T_x nanosheets via an in situ hydrofluoric acid generation method, which was further employed to construct a wearable heating system of MXene @ polyester polyurethane blend fabrics (MP textile) for the passive personal thermal management through a simple spraying process. Owing to the unique two-dimensional (2D) structure, the MP textile presents the desired mid-infrared emissivity, which could efficiently suppress the thermal radiation loss from the human body. Notably, the MP textile with an MXene concentration of 28 mg/mL exhibits a low mid-infrared emissivity of 19.53% at 7-14 μm. Significantly, these prepared MP textiles demonstrate an enhanced temperature of more than 6.83 °C compared with those of favorably traditional fabrics, involving the black polyester fabric, pristine polyester polyurethane blend fabric (PU/PET), and cotton, suggesting a charming indoor passive radiative heating performance. The temperature of real human skin covered by MP textile is 2.68 °C higher than that covered by cotton fabric. Impressively, these prepared MP textiles simultaneously possess attractive breathability, moisture permeability, mechanical strength, and washability, which provide new insight into human body temperature regulation and physical health.

Two-Dimensional Janus MXene Inks for Versatile Functional Coatings on Arbitrary Substrates

Solution processing of two-dimensional nanomaterial inks guarantees efficient, straightforward fabrication of functional films, coatings, flexible devices, etc. Despite the excellent solution processibility and viscoelasticity of MXene aqueous inks, formulation of nonaqueous MXene inks with great affinity to both hydrophilic and hydrophobic substrates has proven quite challenging, limiting the practical applications of MXenes in printing/coatings on various substrates. Here, MXene surface chemistry is manipulated by asymmetrically grafting polystyrene and further concentrating the flakes into additive-free Janus MXene organic inks. The modified MXene nanosheets exhibit hydrophilicity on one side and hydrophobicity on the other. As a result, Janus MXene nanosheets ensure broad dispersibility in polar and nonpolar solvents, which in turn greatly extends the ink shelf life by slowing down the oxidation kinetics. Janus MXene sheets dispersed in toluene at room temperature remain at 90% of the initial solids after 1 month of storage. Janus surface engineering on MXene flakes guarantees the straightforward formation of uniform yet firm, large-area coatings on hydrophilic or hydrophobic substrates. These coatings demonstrate improved photothermal properties and chemical stability as well as good electromagnetic interference shielding performance. This strategy provides a simple and cost-effective way to promote the performance of MXene electronics in a variety of applications.

Elastic Fibers/Fabrics for Wearables and Bioelectronics

Wearables and bioelectronics rely on breathable interface devices with bioaffinity, biocompatibility, and smart functionality for interactions between beings and things and the surrounding environment. Elastic fibers/fabrics with mechanical adaptivity to various deformations and complex substrates, are promising to act as fillers, carriers, substrates, dressings, and scaffolds in the construction of biointerfaces for the human body, skins, organs, and plants, realizing functions such as energy exchange, sensing, perception, augmented virtuality, health monitoring, disease diagnosis, and intervention therapy. This review summarizes and highlights the latest breakthroughs of elastic fibers/fabrics for wearables and bioelectronics, aiming to offer insights into elasticity mechanisms, production methods, and electrical components integration strategies with fibers/fabrics, presenting a profile of elastic fibers/fabrics for energy management, sensors, e-skins, thermal management, personal protection, wound healing, biosensing, and drug delivery. The trans-disciplinary application of elastic fibers/fabrics from wearables to biomedicine provides important inspiration for technology transplantation and function integration to adapt different application systems. As a discussion platform, here the main challenges and possible solutions in the field are proposed, hopefully can provide guidance for promoting the development of elastic e-textiles in consideration of the trade-off between mechanical/electrical performance, industrial-scale production, diverse environmental adaptivity, and multiscenario on-spot applications.

Flexible stretchable electrothermally/photothermally dual-driven heaters from nano-embedded hierarchical CuxS-Coated PET fabrics for all-weather wearable thermal management

The multifunctional photoelectronic devices are recently attracting much more attention due to their potential enlarged applications. The flexible stretchable electrothermally/photothermally dual-driven heaters for all-weather wearable thermal management are presented in this work with nano-embedded hierarchical Cu_xS-coated PET fabrics. Herein, the hierarchical nano-embedded Cu_xS film is fabricated via a simple chemical bath method for high electrical conductivity and highly efficient inelastic collision of electro/photo-generated carriers. The hierarchical nano-embedded Cu_xS morphology produces the low sheet resistance of 1.26 Ω sq^-1 and the super low total heat transfer coefficient of 3.256 × 10^-5 W/^oC·mm², which lead to the high-efficient electro/photo-dual-driven heating effect in the Cu_xS@PET fabrics. The saturated temperature on the as-fabricated flexible wearable heaters reaches up to 172 °C. The thermal conversion devices also bear the excellent stability, reproducibility, stretchability, controllability and corrosion-resistant characteristics. Interestingly, their excellent thermal conversion performance could be achieved by freely exchanging the driving power sources, such as electricity-supplying equipment, 635-nm laser, infrared physiotherapy lamp and solar simulator, which provides a necessary precondition for the all-weather applications of flexible wearable heaters. The as-fabricated electro/photo-dual-driven heaters on the Cu_xS@PET fabrics have the promising applications in wearable electronics, all-weather self-heating facilities, out/in-vivo physiotherapy, and so on.

Radio Frequency Heating of Washable Conductive Textiles for Bacteria and Virus Inactivation

The ongoing COVID-19 pandemic has increased the use of single-use medical fabrics such as surgical masks, respirators, and other personal protective equipment (PPE), which have faced worldwide supply chain shortages. Reusable PPE is desirable in light of such shortages; however, the use of reusable PPE is largely restricted by the difficulty of rapid sterilization. In this work, we demonstrate successful bacterial and viral inactivation through remote and rapid radio frequency (RF) heating of conductive textiles. The RF heating behavior of conductive polymer-coated fabrics was measured for several different fabrics and coating compositions. Next, to determine the robustness and repeatability of this heating response, we investigated the textile's RF heating response after multiple detergent washes. Finally, we show a rapid reduction of bacteria and virus by RF heating our conductive fabric. 99.9% of methicillin-resistant Staphylococcus aureus (MRSA) was removed from our conductive fabrics after only 10 min of RF heating; human cytomegalovirus (HCMV) was completely sterilized after 5 min of RF heating. These results demonstrate that RF heating conductive polymer-coated fabrics offer new opportunities for applications of conductive textiles in the medical and/or electronic fields.

A Trimode Thermoregulatory Flexible Fibrous Membrane Designed with Hierarchical Core-Sheath Fiber Structure for Wearable Personal Thermal Management

Advanced textiles designed for personal thermal management contribute to thermoregulation in an individual and energy-saving manner. Textiles incorporated with phase changing materials (PCMs) are capable of bridging the supply and demand for energy by absorbing and releasing latent heat. The integration of solar heating and the Joule heating function supplies multidriving resources, facilitates energy charging and storage, and expands the service time and application scenarios. Herein, we report a fibrous membrane-based textile that was developed by designing the hierarchical core-sheath fiber structure for trimode thermal management. Especially, coaxial electrospinning allows an effective encapsulation of PCMs, with high heat enthalpy density (106.9 J/g), enabling the membrane to buffer drastic temperature changes in the clothing microclimate. The favorable photothermal conversion performance renders the membrane with the high saturated temperature of 70.5 °C (1 sun), benefiting from the synergistic effect of multiple light harvesters. Moreover, a conductive coating endows the composite membrane with an admirable electrothermal conversion performance, reaching a saturated temperature of 73.8 °C (4.2 V). The flexible fibrous membranes with the integrated performance of reversible phase change, multi-source-driven heating, and energy storage present great advantages for all-day, energy-saving, and wearable individual thermal management applications.

High-Performance and Rapid-Response Electrical Heaters Derived from Cellulose Nanofiber/Silver Nanowire Nanopapers for Portable Thermal Management

High-performance electrical heaters with outstanding flexibility, superior portability, and mechanical properties are highly desirable for portable thermal management. However, it is still a huge challenge to simultaneously achieve competent electrical heating performances and excellent mechanical properties. Herein, inspired by the Janus structure, versatile electrical heaters are developed via a sequential assembly followed by a hot-pressing strategy. The elaborately designed Janus structure is composed of a nanofibrillated cellulose (NFC) layer and a partially wrapped silver nanowire (AgNW) skeleton in the NFC substrate. Owing to the perfect introduction of nano-soldered points induced by thermal welding decoration, the resultant NFC/AgNW papers (NAPs) possess great flexibility, excellent mechanical strength (176.75 MPa), extremely low sheet resistance (0.60 Ω/sq), and superior electrical stabilities against mechanical deformations. Moreover, benefitting from these fascinating attributes, the NAP-based electrical heaters exhibit a remarkable heating temperature (∼220 °C), ultrafast electro-thermal response (<10 s), and groundbreaking long-term stability (∼105 °C for >186 h) and repeatability (>20,000 cycles) with low AgNW contents and driving voltages (0.5-5.0 V), which far surpass those of the previously reported and conventional indium tin oxide-based Joule heaters. Impressively, large-area production feasibilities of NAPs are demonstrated and assembled into multifunctional applications, including personal thermal management, healthcare thermotherapy, multifunctional cups, and smart homes, indicating their promising potential for wearable devices, artificial intelligence, and specific heating systems in the fields of aerospace, military, and intelligent life.

Self-Powered Multifunctional Electronic Skin Based on Carbon Nanotubes/Poly(dimethylsiloxane) for Health Monitoring

Flexible and multifunctional electronic skin (e-skin) has received remarkable attention for its potential applications in health monitoring, human-machine interface, and artificial sensory nerves. However, conventional multifunctional e-skins require complex material systems, sophisticated fabrication, and external power supplies, leading to increased preparation cost and duration, thus hindering their large-scale utilization. Herein, a self-powered multifunctional e-skin system with properties of pressure, temperature, underwater sensing, and photothermal heating is designed based on carbon nanotubes/poly(dimethylsiloxane) (CNT/PDMS) acting as both the multifunctional sensing layer and the cathode of the power supply. Our micropyramidal structured e-skin exhibits outstanding pressure sensitivity (1.51 × 10³ kPa^-1) over a wide sensing range (2.5-255.7 kPa) and maintains ultralong-term durability (>20 000 cycles). It can also provide personalized photothermal therapy at an adjustable temperature (40-110 °C) and heating area under near-infrared irradiation due to the photothermal effect of CNTs, with the temperature being detected synchronously by current signals. Additionally, the hydrophobicity of the CNT/PDMS film endows our device with underwater sensing capability. Furthermore, practical healthcare applications have been demonstrated with reliable signal quality and stability, such as daily activities and underwater movements/temperature monitoring, SOS Morse code communication, and human-machine interface. This work could provide insight on developing simple, stable, and wearable healthcare devices with self-power supply and multifunction.

Ultralight, Superelastic, and Washable Nanofibrous Sponges with Rigid-Flexible Coupling Architecture Enable Reusable Warmth Retention

Nanofibrous sponges enable promising potentials in warmth retention but are impeded by short service life and nonwashability, owing to their inadequate mechanical properties. Herein, a scalable strategy is reported to develop ultralight, superelastic, and washable micro/nanofibrous sponges (MNFSs) with a rigid-flexible coupling architecture created by bridging high-modulus polyethylene terephthalate microfibers with flexible polyacrylonitrile nanofibers via robust bonding structures. Meanwhile, the in situ doping of fluoropolymer endows micro/nanofibers with desirable amphiphobicity. The resultant MNFSs present high resilience, superior compressive fatigue resistance (5.7% residual strain at 1000th), low-temperature-resistant superelasticity (up to -196 °C), and unique washing-invariant superelasticity. Moreover, the fascinating structures of high porosity, high tortuosity, and small pores enable MNFSs both ultralight property (7.5 mg cm^-3) and effective warmth retention (28.51 mW m^-1 K^-1). Additionally, the MNFSs possess remarkable antifouling, robust stability, and long service life. The work might provide an avenue to develop mechanically robust nanofibrous sponges for various applications.

Floating Ag-NPs@Cu-NW bundles fabricated on copper mesh for highly sensitive SERS detection of uric acid in pretreatment-free urine

Bundle-like structures decorated with Ag nanoparticles can be used as active floating SERS substrates with abundant 3D hot spots for highly sensitive detection of uric acid based on capillary forces that drive target molecules into the hot spots.

Wearable Ultrahigh Current Power Source Based on Giant Magnetoelastic Effect in Soft Elastomer System

In this study, we present the observation of the giant magnetoelastic effect that occurs in soft elastomer systems without the need of external magnetic fields and possesses a magnetomechanical coupling factor that is four times larger than that of traditional rigid metal-based ferromagnetic materials. To investigate the fundamental scientific principles at play, we built a linear model by using COMSOL Multiphysics, which was consistent with the experimental observations. Next, by combining the giant magnetoelastic effect with electromagnetic induction, we developed a magnetoelastic generator (MEG) for biomechanical energy conversion. The wearable MEG demonstrates an ultrahigh output current of 97.17 mA, a low internal impedance of around ∼40 Ω, and an intrinsic waterproof property. We further leveraged the wearable MEG as an ultrahigh current power source to drive a Joule-heating textile for personalized thermoregulation, which increased the temperature of the fiber-shaped resistor by 0.2 °C. The development of the wearable MEG will act as an alternative and compelling approach for on-body electricity generation and arouse a wide range of possibilities in the renewable energy community.

Biomass-Derived, Highly Conductive Aqueous Inks for Superior Electromagnetic Interference Shielding, Joule Heating, and Strain Sensing

Conductive composite inks are widely used in various applications such as flexible electronics. However, grand challenges still remain associated with their relatively low electrical conductivity and require heavy use of organic solvents, which may limit their high performance in broad applications and cause environmental concerns. Here, we report a generalized and eco-friendly strategy to fabricate highly conductive aqueous inks using silver nanowires (AgNWs) and biomass-derived organic salts, including succinic acid-chitosan (SA-chitosan) and sebacic acid-chitosan. SA-chitosan/AgNW composite coatings can be prepared by directly casting conductive aqueous inks on various substrates, followed by subsequently heating for cross-linking. The composite coatings exhibit an ultrahigh electrical conductivity up to 1.4 × 10⁴ S/cm, which are stable after being treated with various organic solvents and/or kept at a high temperature of 150 °C, indicating their high chemical and thermal resistance. The flexibility and performance durability of these composite coatings were demonstrated by a suite of characterization methods, including bending, folding, and adhesion tests. Moreover, a high electromagnetic interference shielding (EMI) effectiveness of 73.3 dB is achieved for SA-chitosan/AgNW composite coatings at a thickness of only 10 μm due to the ultrahigh electrical conductivity. Additionally, we further demonstrated that such conductive composite inks can be used for fabricating functional textiles for a variety of applications with high performance, such as EMI shielding, Joule heating, and strain sensing. The robust and highly conductive inks prepared by this simple and environmental-friendly method hold great promise as important material candidates for the potential large-scale manufacturing of flexible and wearable electronics.

Progress in Flexible Electronic Textile for Heating Application: A Critical Review

Intelligent textiles are predicted to see a 'surprising' development in the future. The consequence of this revived interest has been the growth of industrial goods and the improvement of innovative methods for the incorporation of electrical features into textiles materials. Conductive textiles comprise conductive fibres, yarns, fabrics, and finished goods produced using them. Present perspectives to manufacture electrically conductive threads containing conductive substrates, metal wires, metallic yarns, and intrinsically conductive polymers. This analysis concentrates on the latest developments of electro-conductivity in the area of smart textiles and heeds especially to materials and their assembling processes. The aim of this work is to illustrate a potential trade-off between versatility, ergonomics, low energy utilization, integration, and heating properties.

Smart Textiles Based on MoS2 Hollow Nanospheres for Personal Thermal Management

Two-dimensional transition metal dichalcogenides are of particular interest in high-performance photothermal conversion, yet there remains a huge challenge in their practical application in smart textiles for healthcare, energy, and personal protection. Herein, we controllably prepared MoS₂ hollow nanospheres with a high photothermal conversion efficiency of 36% via a microemulsion-hydrothermal method, which was further applied to construct photothermal fibers for personal thermal management after a hot-blast dip-drying process. Because of the prominent photothermal effect, the temperature of the photothermal fibers sharply increases from the room temperature value of 25.0 to 55.5 °C in 60 s under near-infrared illumination with a power density of 500 W/cm². Furthermore, the photothermal fiber pad demonstrated an obvious temperature enhancement of 38.0 °C from a skin temperature of 22.0 °C after it was irradiated by natural sunlight for 60 s. Significantly, the antibacterial elimination rates of the photothermal fibers for Escherichia coli and Staphylococcus aureus are ∼99.9 and ∼99.8%, respectively. This strategy affords an avenue toward the practical application of photothermal materials in smart fibers for personal thermoregulation.