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Aerogel fibers, the simultaneous embodiment of aerogel porous network and fiber slender geometry, have shown critical advantages over natural and synthetic fibers in thermal insulation. However, how to control the building block orientation degree of the resulting aerogel fibers during the dynamic sol-gel transition process to expand their functions for emerging applications is a great challenge. Herein, nanoscale Kevlar liquid crystal (NKLC) aerogel fibers with different building block orientation degrees have been fabricated from Kevlar nanofibers

Background Cardiovascular diseases is increasingly identified to be related to the restless legs syndrome (RLS). However, the relationship between Cardiovascular Health Metric (CVH) and RLS need to be further confirmed. The present study aimed to assess the association of overall CVH metric and 7 Simple’s Life (LS7) with the RLS risk. Methods In a cross-sectional population-based study, 3,772 adults (57.6 ± 5.11 years of age) were recruited and completed the structured questionnaire between January 2 and May 21, 2022. Blood sample and other body measurements were obtained by trained nurses. The definition and score of CVH metric was determined by the attendance of LS7, and the RLS was diagnosed by the International Restless Legs Syndrome Study Group (IRLSSG) criteria. Multivariate logistic regression models were applied to examine the associations of overall CVH metric and its SL7 profiles with prevalence of RLS. Results Overall, 301 (7.98%) were diagnosed with RLS. Multivariable logistic regression analysis showed that, in comparison to inadequate scores, higher scores of overall CVH metric and body mass index (BMI), physical activity, blood pressure and total cholesterol (TC) metric were negatively associated with the prevalence of RLS (multi-adjusted odd ratios [ORs] ranged from 0.32 to 0.67, all P for trend < 0.05). Per 1-SD increase in over CVH metric and each SL7 profile yielded the similar results (ORs ranged from 0.65 to 0.85, all P for trend < 0.05). Significant differences in the association of RLS with smoke profile and overall CVH metric were detected with females (P for interaction = 0.005) and older participants (P for interaction = 0.013), respectively. Conclusion To be at an ideal behavioural CVH may be benefit in RLS, especially for women and older people. Interventions concerning to promote and preserve favourable CVH should be regarded in the prevention and treatment of RLS.

Aerogel films with a low density are ideal candidates to meet lightweight application and have already been used in a myriad of fields; however, their structural design for performance enhancement remains elusive. Herein, we put forward a laminated structural engineering strategy to prepare a free-standing carbon nanotube (CNT)-based aerogel film with a densified laminated porous structure. By directional densification and carbonization, the three-dimensional network of one-dimensional nanostructures in the aramid nanofiber/carbon nanotube (ANF/CNT) hybrid aerogel film can be reconstructed to a laminated porous structure with preferential orientation and consecutively conductive pathways, resulting in a large specific surface area (341.9 m

Aerogels represent a kind of nanoporous solid with immense importance for a plethora of diverse applications. However, on-demand conformal shaping capacity remains extremely challenging due to the strength unfavorable during aerogel processing. Herein, a universal microgel-directed suspended printing (MSP) strategy is developed for fabricating various mesoporous aerogels with spatially stereoscopic structures on-demand. As a proof-of-concept demonstration, through the rational design of the used microgel matrix and favorable printing of the Kevlar nanofiber inks, the Kevlar aerogels with arbitrary spatial structure have been fabricated, demonstrating excellent printability and programmability under a high-speed printing mode (up to 167 mm s

Gels are soft functional materials with solid networks and open pores filled with solvents (for wet gels) or air (for aerogels), displaying broad applications in tissue engineering, catalysis, environmental remediation, energy storage, etc. However, currently known gels feature only a single (either solid-liquid or solid-vapor) interface, largely limiting their application territories. Therefore, it is both fundamentally intriguing and practically significant to develop conceptually new gel materials that possess solid-liquid-vapor multiple interfaces. Herein, we demonstrate a unique solid-liquid-vapor triphase gel, named as aerohydrogel, by gelling of a poly(vinyl alcohol) aqueous solution with glutaraldehyde in the presence of superhydrophobic silica aerogel microparticles. Owing to its continuous solid, liquid, and vapor phases, the resultant aerohydrogel simultaneously displays solid-liquid, solid-vapor, and liquid-vapor interfaces, leading to excellent properties including tunable density (down to 0.43 g·cm-3), considerable hydrophobicity, and excellent elasticity (compressive ratio of up to 80%). As a proof-of-concept application, the aerohydrogel exhibits a higher evaporative cooling efficiency than its hydrogel counterpart and a better cooling capability than the commercial phase change cooling film, respectively, showing promising performance in cooling various devices. Moreover, the resulting aerohydrogel could be facilely tailored with specific (e.g., magnetic) properties for emerging applications such as solar steam generation. This work extends biphase gel (hydrogel or aerogel) to solid-liquid-vapor triphase gel, as well as provides a promising strategy for designing more aerohydrogels serving as soft functional materials for applications in various emerging fields.

Hemostatic materials have played a significant role in mitigating traumatic injury by controlling bleeding, however, the fabrication of the desirable material's structure to enhance the accumulation of blood cells and platelets for highly efficient hemostasis is still a great challenge. In this work, directed assembly of poly(vinyl alcohol) (PVA) macromolecules covering the rigid Kevlar nanofiber (KNF) network during 3D printing process is utilized to fabricate hydrophilic, biocompatible, and mechanically stable KNF-PVA aerogel filaments for effective enriching blood components by fast water absorption. As such, KNF-PVA aerogel gauzes demonstrate remarkable water permeability (338 mL cm

Smart and functional fibers have demonstrated great potentials in a wide range of applications including wearable devices and other high-tech fields, but design and fabrication of smart fibers with manageable structures as well as versatile functions are still a great challenge. Herein, an ingenious bending-stiffness-directed strategy is developed to fabricate smart phase-change fibers with different bending stiffnesses for diverse applications. Specifically, the hydrophobic Kevlar aerogel-confined paraffin wax fibers (PW@H-KAF) are fabricated by employing hydrophobic Kevlar aerogel fibers (H-KAFs) as the porous host and paraffin as the functional guest, where the H-KAF is obtained by applying a two-step process to functionalize Kevlar nanofibers (KNFs) with a special coagulation bath containing a mixture of ethanol and n-bromobutane. The prepared PW@H-KAFs exhibit high latent heat (135.1-172 J/g), outstanding thermal cyclic stability and satisfactory mechanical properties (30 MPa in tensile strength and 30% in tensile strain). In addition, the PW@H-KAFs with bending stiffness was lower than the critical one (1.22 × 10-9 N·m2) even in a solid state of paraffin wax exhibits high flexibility, washable performance, and high thermal management capability, showing great potential for smart temperature-regulating fabrics. PW@H-KAFs with a bending stiffness higher than the critical one at a solid state of paraffin wax can be utilized as shape memory materials, attributed to the transition between rigidity and flexibility caused by the phase transition. As a proof of concept, a dynamic gripper is designed based on the PW@H-KAF (400 μm in diameter) for transporting items by gripping in the rigid state and releasing in the flexible state. This work realizes versatile applications with the PW@H-KAFs through the bending stiffness-directed method, providing ideas for the application of phase-change composites.

Aerogel fibers with ultrahigh porosity, large specific surface area, and ultralow density have shown increasing interest due to being considered as the next generation thermal insulation fibers. However, it is still a great challenge to fabricate arbitrary aerogel fibers via the traditional wet-spinning approach due to the obvious conflict between the static sol-gel transition of the aerogel bulks and the dynamic wet-spinning process of aerogel fibers. Herein, a sol-gel confined transition (SGCT) strategy was developed for fabricating various mesoporous aerogel fibers, in which the aerogel precursor solution was first driven by the surface tension into the capillary tubes, then the gel fibers were easily formed in the confined space after static sol-gel process, and finally the mesoporous aerogel fibers were obtained via the supercritical CO2 drying process. As a typical case, the polyimide (PI) aerogel fiber prepared via the SGCT approach has exhibited a large specific surface area (up to 364 m2/g), outstanding mechanical property (with elastic modulus of 123 MPa), superior hydrophobicity (with contact angle of 153°), and excellent flexibility (with curvature radius of 200 μm). Therefore, the aerogel woven fabric made from PI aerogel fibers has possessed an excellent thermal insulation performance in a wide temperature window, even under the harsh environment. Besides, arbitrary kinds of aerogel fibers, including organic aerogel fibers, inorganic aerogel fibers, and organic-inorganic hybrid aerogel fibers, have been fabricated successfully, suggesting the universality of the SGCT strategy, which not only provides a way for developing aerogel fibers with different components but also plays an irreplaceable role in promoting the upgrading of the fiber fields.

Harvesting and transforming water energy into electricity via nanostructured materials, which is termed hydrovoltaic power generation (HPG), has attracted increasing interest in the past few decades. However, the current limitation of HPG devices taking advantage of the electrokinetic effect is their poor power density within microwatts per square meter. Herein, a novel catalytic graphene aerogel film decorated with an interlayer catalyst of α-FeOOH was developed successfully. Upon the addition of H2O2 to a saline (NaCl) droplet, an exceptionally high voltage of 0.63 V was achieved, which is around 20 times higher than the previously reported value using single-layer graphene. The experimental and theoretical results showed that the high hydrovoltaic performance originates from three contributions. Firstly, the large droplet/graphene interfaces, benefitting from the high specific surface area of the aerogel and the bubbling effect produced by the catalytic decomposition of H2O2via α-FeOOH. Secondly, the enhanced electrokinetic effect, i.e., increased hydrated ion radius of NaCl and suppressed shielding effect between cations and anions in the presence of H2O2, which dramatically extends the NaCl concentration window from 0.6 M to 5.0 M. Thirdly, utilizing the advantage of electrochemical reactions related to H2O2 in the saline (NaCl) droplet to greatly increase the short-circuit current of the HPG device. The outcome of these contributions is a much higher ion utilization efficiency under a high saline concentration, which breaks the output bottleneck of power density caused by using a low saline concentration. Our work extends the device component from single-layer graphene to a 3D porous graphene aerogel, making a significant step forward for the future development of HPG devices.

Solar steam generation and marine uranium extraction are promising methods for obtaining sufficient fresh water and nuclear fuel from the ocean, respectively, for overcoming water and energy crises. In this work, a bayberry tannin (BT) directed assembly of a bifunctional graphene aerogel (GA) has been designed for simultaneous solar steam generation (1.80 kg m-2 h-1 with a high solar efficiency of 95.5%) and marine uranium extraction (230.10 mg g-1 within 6 h). BT molecules are uniformly decorated inside the typical porous channels of GA, which integrates the excellent uranium binding of BT and the efficient light-to-heat conversion of GA. It is found that the hydrophilic nature of BT can improve fluid infiltration in the GA matrix for solar steam generation while the steam generation induced transpiration can accelerate the adsorption of uranium ions for marine uranium extraction. The unique bifunctional ability of the BT-GA composite paves a new way to utilize the abundant resources in the ocean.

With the advent of the 5G era, electronic systems have become more and more powerful, miniaturized, integrated ,and intelligent. The thermal management of electronic systems requires more efficiency and multiple functions for their practical applications, especially for the portable 5G electronic devices of the future, as the undesired heat can cause thermal discomfort or even thermal injury to people who use these electronic devices. Herein, two thermal management strategies based on boron nitride (BN) aerogel films have been proposed and demonstrated for portable devices. First, a flexible BN aerogel film with high porosity (>96%), large specific surface area (up to 982 m2 g-1), and controllable thickness (in the range from 50 to 200 μm) was fabricated via molecular precursor assembly, sublimation drying, and pyrolysis reaction in sequence. The resulting BN aerogel film individuals, serving as a thermal insulation protecting layer in portable electronics, can significantly reduce heat transfer from electronics to skin. Second, BN phase change composite films, made by dipping BN aerogel films into the melts of the organic phase change materials (e.g., paraffin), can effectively cool the portable electronics as the organic phase change materials filled in the aerogel matrix can serve as a smart thermal-regulator to absorb the undesired heat via solid-liquid phase transition. These two typical strategies of the flexible BN aerogel film-directed thermal management could assist in efforts to miniaturize, integrate, and intelligentialize portable 5G electronic devices in the future.

Aerogel fibers, the simultaneous embodiment of aerogel 3D network and fibrous geometry, have shown great advantages over natural and synthetic fibers in thermal insulation. However, as a fast gelation to ensure aerogel fiber spinning generally induces rapid local clustering of precursor particles (

Lithium ion batteries are the most feasible energy storage technology for modern society. However, the electrochemical performance of commercial products is not satisfactory, which severely limits ...

A proton exchange membrane fuel cell (PEMFC) system with a hydrogen generator could have higher energy density than flexible batteries and supercapacitors and is possible to meet the urgent demand of flexible electronics. However, a flexible PEMFC pack is still not available due to the absence of a flexible hydrogen generator. To solve this problem, we successfully invented a flexible and adaptable hydrogen generator, which was realized by a new bifunctional aerogel catalyst with the abilities of both storing and producing hydrogen. The flexible hydrogen generator can produce hydrogen at room temperature when the device is inverting, bending, and rotating. By combining this flexible hydrogen generator and the unique flexible PEMFC stack of our group, we originally made a highly flexible and adaptable fuel cell pack with a high theoretical energy density (up to 722 Wh·kg

Auxetic architectures with a negative Poisson's ratio have attracted increasing attention due to their intriguing physical properties and numerous promising applications and recent advancements in manufacturing techniques. However, fabrication of three-dimensional (3D) polymeric auxetic architectures with a tailored hierarchically porous structure and desired physical/mechanical properties remains challenging. Herein, 3D nanofibrous Kevlar aerogel architectures with porosity at multiple scales have been designed and fabricated through a new additive manufacturing strategy, i.e., integration of direct ink writing and freeze-casting with non-toxic solvent-based inks followed by special drying techniques. The highly porous 3D nanofibrous Kevlar aerogel architectures achieve excellent mechanical properties with an ultralow density (down to 11.9 mg cm−3) and large specific surface area (up to 350 m2 g−1). The Poisson's ratio is tunable in a wide range, spanning from −0.8 to 0.4, by adjusting the spatial arrangement of the designed pattern struts. Finally, these nanofibrous Kevlar aerogel architectures have been further functionalized into hydrophobic, luminescent and thermoresponsive architectures by using fluorocarbon resin, functional dyes and organic phase-change materials respectively. The multi-functional auxetic aerogel architectures demonstrate potential for a broad range of applications.

Melphalan (MEL) is an effective chemotherapeutic agent for treatment of retinoblastoma (Rb) which is the most common childhood malignancy. However, the inherent cardiopulmonary toxicity and hazardous integration limit its therapeutic effect on RB. N-Acetylheparosan (AH), a natural heparin-like polysaccharide in mammals with long circulation effect and good biocompatibility, was linked by d-α-tocopherol acid succinate (VES) via and cystamine (CYS) to synthesize reduction-responsive N-acetylheparosan-CYS-Vitamin E succinate (AHV) copolymers. In addition, CYS was replaced by adipic acid dihydrazide (ADH) to obtain a control of non-reduction-responsive polymers N-acetylheparosan-ADH-Vitamin E succinate (ADV). MEL-loaded AHV micelles (MEL/AHV) as well as ADV micelles (MEL/ADV) were prepared with small particle size and high drug loading content. In vitro drug release showed that MEL/AHV micelles presented obvious reduction-triggered release behavior compared with MEL/ADV. In vitro antitumor effects were investigated using WERI-Rb-1 retinoblastoma cells. Cytotoxicity experiments showed that the IC50 of MEL/AHV was significantly lower than that of free MEL and MEL/ADV, suggesting that MEL/AHV enhanced the cytotoxicity against retinoblastoma cells. Furthermore, MEL/AHV micelles were more easily uptaken by multiple pathways compared with MEL/ADV and free MEL. Therefore, MEL/AHV might be a potential delivery system for enhanced delivery of melphalan to Rb cells.

Aerogel fibers have been recognized as the rising star in the fields of thermal insulation and wearable textiles. Yet, the lack of functionalization in aerogel fibers limits their applications. Herein, we report hygroscopic holey graphene aerogel fibers (LiCl@HGAFs) with integrated functionalities of highly efficient moisture capture, heat allocation, and microwave absorption. LiCl@HGAFs realize the water sorption capacity over 4.15 g g−1, due to the high surface area and high water uptake kinetics. Moreover, the sorbent can be regenerated through both photo-thermal and electro-thermal approaches. Along with the water sorption and desorption, LiCl@HGAFs experience an efficient heat transfer process, with a heat storage capacity of 6.93 kJ g−1. The coefficient of performance in the heating and cooling mode can reach 1.72 and 0.70, respectively. Notably, with the entrapped water, LiCl@HGAFs exhibit broad microwave absorption with a bandwidth of 9.69 GHz, good impedance matching, and a high attenuation constant of 585. In light of these findings, the multifunctional LiCl@HGAFs open an avenue for applications in water harvest, heat allocation, and microwave absorption. This strategy also suggests the possibility to functionalize aerogel fibers towards even broader applications.

Graphene aerogel fibers (GAFs) with low density, high specific surface area, and high porosity can be used as the host material to incorporate another component and thus form multifunctional fibers, which have potential applications in wearable devices, thermoregulating apparatus, sensors, and so forth. However, the intrinsically low electric conductivity of GAFs hampers them in the fields of electrothermal heating and electromagnetic interference (EMI) shielding. Herein, we report a new aerogel fiber composed by graphene sheets and nickel nanoparticles with low density (55-192 mg/cm3), high electric conductivity (0.8 × 103 to 4.5 × 104 S/m), and high specific surface area (49-105 m2/g). The graphene/Ni aerogel fibers (GNAFs) were synthesized initially from reduced graphene oxide hydrogel fibers followed by an electroless plating process. Further investigations have demonstrated that the resulting GNAFs possess excellent electrothermal property, faster electrothermal response, high mechanical and electrical stability as the electric wire, and excellent EMI shielding performance as the composite filler. The saturated temperature of GNAFs can reach 174 °C with an applied voltage of only 5 V, and the heating rate surpasses those of commercial Kanthal and Nichrome wires about 2.1 times and 2.6 times, respectively. The EMI shielding effectiveness of GNAFs is higher than 30 dB at the long bandwidth of 12.5-20 GHz. Specifically, it can shield more than 99.99% of the incident wave at the bandwidth of 15-20 GHz.

Phase change materials offer enormous potential for thermal energy storage due to their high latent heat and chemical stability. Researchers have developed numerous innovative strategies to overcome the leakage of organic phase change materials and enhance thermal performance. However, the manufacture of form-stable, free-standing energy storage films based on phase change materials with high latent heat remains difficult. Therefore, the present study focused on the production of free-standing, form-stable energy storage films with high phase-change enthalpy and thermally stimulant multiresponsiveness from the simple composite of paraffin with a polytetrafluoroethylene/silica (PTFE/SiO

The design and synthesis of solar steam generation materials have received considerable attention due to their capacity to produce freshwater from seawater or contaminated water by a straightforward utilisation of solar energy. The practical application of these materials, however, is restricted by their low evaporation efficiency and non-durable floating capacity on water. Herein, flexible and self-floating polyvinyl alcohol (PVA) based hybrid hydrogels for solar steam generation are designed and synthesized by assembling two types of functional particles within the network: conducting polymer hollow spheres (CPHSs) for achieving solar absorption and heat conversion, and silica aerogel microparticles for density reduction and efficient energy conversion confined to a small amount of surrounding water. Following a freezing process, functionalized hybrid hydrogels with macro-sized channels are generated, contributing to rapid water supply. The Janus surface nature, with one side being hydrophilic (contact angle ca. 60°) and another hydrophobic (contact angle up to 135°), of the hybrid hydrogel was found due to the formation of a gradient distribution of silica aerogel particles via controlling the gelation conditions. Consequently, the density of the hybrid hydrogels is controlled in the range of 0.8–1.0 g cm−3 and the thermal conductivity of the corresponding xerogels in the range of 0.030–0.035 W m−1 K−1, depending on the content of the silica aerogels. High water production of the hybrid hydrogel at a rate of 1.83 kg m−2 h−1 under 1 sun illumination has been demonstrated, which is an important step towards a cost-effective solution for the scarcity of clean water.

Aerogel is a kind of high-performance lightweight open-porous solids with ultralow density, high specific surface area, and broad application in many emerging fields including biotechnology, energy, environment, aerospace, etc. A giant challenge remains in preventing of the hydrophilic aerogel framework shrinkage when replacing of solvent with air in its extremely abundant nanosized pores during its fabrication process in ambient conditions. In this work, started from a linear polymeric precursor with further condensation reaction, superhydrophilic silica aerogels with self-reinforced microstructure and the least volume shrinkage have been successfully obtained via ambient pressure drying process without use of any additives in the presence of a low surface tension solvent. The resulting superhydrophilic silica aerogels possess specific surface area up to 1065 m2/g, pore volume up to 2.17 cm3/g and density down to 84 mg/cm3, and these values are comparable to those of their counterparts obtained by supercritical CO2 drying process. Moreover, as an application demonstration, the bioinspired hydrogels with desirable mechanical flexibility and adhesive performance at extremely harsh environment (e.g., below -50 °C) have been successfully synthesized by mimicking carrier of a functional bioagent with the resulting superhydrophilic silica aerogel microparticles. Our work has made a significant step forward for future high-performance hydrophilic aerogels with self-enhanced microstructures and the resulting superhydrophilic aerogels have shown great potentials in making functional hydrogels with bionic properties.

A robust silica–polyimide (PI) aerogel blanket is designed and synthesized using the PI foam as the matrix and silica aerogel as the filler through an in situ method, where sol–gel transition of silica precursor occurs in pores of the PI foam, followed by the hydrophobization and ambient pressure drying. The density of the aerogel blanket ranges from 0.036 to 0.196 g/cm3, and the low density is directly controlled by tailoring the silica concentration. The specific surface area of the aerogel blanket reaches 728 m2/g. These features of the blanket result in a low thermal conductivity of 0.018 W/mK, which shows a remarkable reduction of 59% compared to that of the PI foam (0.044 W/mK). As a result, a remarkable decrease of 138°C is achieved using the silica blanket as the thermal insulator on a hot plate of approximately 250°C. In addition, the temperature degradation of the blanket is around 500°C, and up to 86% of mass remaining at 900°C is obtained. The blanket is resistant at extremely harsh conditions, e.g., 600°C for 30 min and 1,300°C for 1 min, and no open flame is observed, suggesting a significant flame-retardant of the blanket. Owing to the three-dimensional (3D) porous framework of the PI foam, the silica aerogel is encapsulated in the PI foam and the blanket exhibits strong mechanical property. The silica–PI aerogel can be reversibly compressed for 50 cycles without reduction of strain. The contact angle of the blanket is 153°, which shows a superior waterproof property. Combining with the low density, low thermal conductivity, flame-retardant, and strong mechanical strength, the aerogel blanket has the potential as an artificial island, which is safe (waterproof and flame-retardant), lightweight, comfortable, and easy to be moved.

Lightweight, robust, and thin aerogel films with multifunctionality are highly desirable to meet the technological demands of current society. However, fabrication and application of these multifunctional aerogel films are still significantly underdeveloped. Herein, we demonstrate a multifunctional aerogel film composed of strong aramid nanofibers (ANFs), conductive carbon nanotubes (CNTs), and hydrophobic fluorocarbon (FC) resin. The obtained hybrid aerogel film exhibits large specific surface area (232.8 m2·g-1), high electrical conductivity (230 S·m-1), and excellent hydrophobicity (contact angle of up to 137.0°) with exceptional Joule heating performance and supreme electromagnetic interference (EMI) shielding efficiency. The FC coating renders the hydrophilic ANF/CNT aerogel films hydrophobic, resulting in an excellent self-cleaning performance. The high electrical conductivity enables a low-voltage-driven Joule heating property and an EMI shielding effectiveness (SE) of 54.4 dB in the X-band at a thickness of 568 μm. The specific EMI SE is up to 33528.3 dB·cm2·g-1, which is among the highest values of typical metal-, conducting-polymer-, or carbon-based composites. This multifunctional aerogel film holds great promise for smart garments, electromagnetic wave shielding, and personal thermal management systems.