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Abstract Recently, solar‐driven interfacial evaporation (SDIE) has been developed quickly for low‐cost and sustainable seawater desalination, but addressing the conflict between a high evaporation rate and salt rejection during SDIE is still challenging. Here, a spatial confinement strategy is proposed to prepare the gel composite solar evaporator (SCE) by loading one thin hydrogel layer onto the skeleton of a carbon aerogel. The SCE retains the hierarchically porous structure of carbon aerogels with an optimized water supply induced by dual‐driven forces (capillary effects and osmotic pressure) and takes advantage of both aerogels and hydrogels, which can gain energy from air and reduce water enthalpy. The SCE has a high evaporation rate (up to 4.23 kg m−2 h−1 under one sun) and excellent salt rejection performance and can maintain structural integrity after long‐term evaporation even at high salinities. The SDIE behavior, including heat distribution, water transport, and salt ion distribution, is investigated by combining theoretical simulations and experimental results. This work provides new inspiration and a theoretical basis for the development of high‐performance interfacial evaporators.

Chronic wounds pose a global public health challenge, particularly in remote settings where access to specialised wound care and dressings can be limited and cost-prohibitive. First Nations communities in Australia are at a significantly higher risk for developing chronic wounds and this risk further increases for people living in remote regions. There is an urgent need to develop inexpensive but effective wound dressings to improve wound outcomes. Over the past decade, sodium alginate (SA)-based hydrogel polymers have emerged as a cost-effective and biocompatible component in wound dressings, and many have been successfully commercialised. In this study, we have developed and evaluated various prototypes of SA-based hydrogels with the addition of another low-cost component, aloe vera (AV) to further tailor the physicochemical properties of the hydrogel. Since the presence of microbes is a major contributor to the pathophysiology of chronic wounds, we also evaluated the antimicrobial activity of lemon myrtle oil (LMO) (Backhousia citriodora) incorporated into the hydrogel, a remedy used traditionally by First Nations Australians. Novel formulations of AV-SA-LMO hydrogel prototypes in the absence and presence of lemon myrtle oil (at a concentration of 5 μg/mL) were assessed for their physicochemical and antimicrobial properties and compared to a commercially available hydrogel-based dressing. The addition of lemon myrtle oil imparted viscoelastic behaviour for improved processability of AV-SA-LMO hydrogel prototypes, while increasing protein adhesion, enhancing physical properties, and demonstrating antimicrobial activity against the common wound-infecting microbes Staphylococcus epidermidis and Candida albicans. Fourier transmission infrared (FTIR) spectra confirmed the molecular structures of the hydrogel prototypes as predicted. The prototypes also demonstrated biocompatibility with the HaCaT human keratinocyte cell line. This study has provided preliminary evidence that a 25:75 aloe vera:sodium alginate hydrogel with 5 μg/mL lemon myrtle oil has comparable physicochemical characteristics to a commercial hydrogel-based wound dressing and antimicrobial properties against S. epidermidis and C. albicans.

Abstract In human life, respiration serves as a crucial physiological signal. Continuous real‐time respiration monitoring can provide valuable insights for the early detection and management of several respiratory diseases. High‐sensitivity, noninvasive, comfortable, and long‐term stable respiration devices are highly desirable. In spite of this, existing respiration sensors cannot provide continuous long‐term monitoring due to the erosion from moisture, fluctuations in body temperature, and many other environmental factors. This research developed a wearable thermal‐based respiration sensor made of cubic silicon carbide (3C‐SiC) using a microfabrication process. The results showed that as a result of the Joule heating effect in the robustness 3C‐SiC material, the sensor offered high sensitivity with the negative temperature coefficient of resistance of approximately 5,200ppmK‐1, an excellent response to respiration and long‐term stability monitoring. Furthermore, by incorporating a deep learning model, this fabricated sensor can develop advanced capabilities to distinguish between the four distinct breath patterns: slow, normal, fast, and deep breathing, and provide an impressive classification accuracy rate of ≈ 99.7%. The results of this research represent a significant step in developing wearable respiration sensors for personal healthcare systems.

Abstract MXene‐based thermal camouflage materials have gained increasing attention due to their low emissivity, however, the poor anti‐oxidation restricts their potential applications under complex environments. Various modification methods and strategies, e.g., the addition of antioxidant molecules and fillers have been developed to overcome this, but the realization of long‐term, reliable thermal camouflage using MXene network (coating) with excellent comprehensive performance remains a great challenge. Here, a MXene‐based hybrid network comodified with hyaluronic acid (HA) and hyperbranched polysiloxane (HSi) molecules is designed and fabricated. Notably, the presence of appreciated HA molecules restricts the oxidation of MXene sheets without altering infrared stealth performance, superior to other water‐soluble polymers; while the HSi molecules can act as efficient cross‐linking agents to generate strong interactions between MXene sheets and HA molecules. The optimized MXene/HA/HSi composites exhibit excellent mechanical flexibility (folded into crane structure), good water/solvent resistance, and long‐term stable thermal camouflage capability (with low infrared emissivity of ≈0.29). The long‐term thermal camouflage reliability (≈8 months) under various outdoor weathers and the scalable coating capability of the MXene‐coated textile enable them to disguise the IR signal of various targets in complex environments, indicating the great promise of achieved material for thermal camouflage, IR stealth, and counter surveillance.

Abstract High‐performance polymers have proliferated in modern society across a variety of industries because of their low density, good chemical stability, and superior mechanical properties. However, while polymers are widely applied, frequent fire disasters induced by their intrinsic flammability have caused massive impacts on human beings, the economy, and the environment. Supramolecular chemistry has recently been intensively researched to provide fire retardancy for polymers via the physical barrier and char‐catalyzing effects of supramolecular aggregates. In parallel, the noncovalent interactions between supramolecular and polymer chains, such as hydrogen bonding, π–π interactions, metal–ligand coordination, and synergistic interactions, can endow the matrix with enhanced mechanical strength. This makes it possible to integrate physical–chemical properties and noncovalent interactions into one supramolecular aggregate‐based high‐performance polymeric system on demand. However, fulfilling these promises needs more research. Here, we provide an overview of the latest research advances of fire‐retardant and high‐strength polymer materials based on supramolecular structures and interactions of aggregates. This work reviews their conceptual design, characterization, modification principles, performances, applications, and mechanisms. Finally, development challenges and perspectives on future research are also discussed.

Abstract Flexible piezoresistive‐sensing materials with high sensitivity and stable sensing signals are highly required to meet the accurate detecting requirement for human motion. Herein, a conductive poly(3,4‐ethylenedioxythiophene): poly(styrenesulfonate) / polydimethylsiloxane foam (P:P@p‐PSF) composite with strong interfacial action is designed. The porous structures and good interface combination not only show outstanding mechanical flexibility and reliability but also possess high sensitivity at a relatively wide strain range. The P:P@p‐PSF sensor achieves extreme sensitivity (Gauge Factor) of 6.25 in the subtle strain range of 1%–8%. Furthermore, the sensor forms a highly interconnected conductive network induced by the serious deformation of elastic‐interconnect pores, thus providing extremely sensitive sensing behavior for a relatively wide strain range (97.4% resistance change rate at 60% compressive strain). Moreover, the sensor presents repeatable stability and good thermal adaptation, which would meet the critical requirements of subtle vital signs, human motion monitoring, and so on. This work supplies insight into the design of a new flexible sensor material to overcome the weak interface problem and the flexible mismatch between conductive filler and matrix, showing great application potential in the field of electronic skin.

Highlights A nanofiber composite reinforced organohydrogel with multifunctionality is prepared. The composite organohydrogel possesses multiple interfacial bondings and multi-level strengthening and toughening mechanism is proposed. The composite organohydrogel exhibits long-term strain sensing stability and can be used for high performance electromagnetic interference shielding.

The design of fully biological flame retardants is vital for environment-friendly and sustainability development. Herein, a fully biological hyperbranched flame retardant named PA-DAD was synthesized successfully through a simple neutralization reaction between 1,10-Diaminodecane (DAD) and phytic acid (PA). PA-DAD as a kind of reactive flame retardant was subsequently employed to composite with epoxy resin (EP). The obtained EP composite, comprising 25 wt% PA-DAD, exhibited excellent flame resistance with an appreciative limiting oxygen index (LOI) of 28.0%, and a desired V-0 rating of UL-94. The favorable attributes stem from the evident flame-retardant characteristics of PA-DAD, manifesting particularly within the gaseous and condensed phases of combustion. Benefitting from the PA-DAD with the synergetic effect of smoke suppression and flame resistance, the EP/25% PA-DAD composite displayed highlighted reductions both in smoke production and heat release rate. In contrast with neat EP, total smoke production (TSP), peak smoke production release (pSPR), the peak heat release rate (pHRR), and the rate of fire growth (FIGRA) of the EP/25% PA-DAD composite were decreased by 49.5%, 57.0%, 72.2% and 77.8%, respectively. Moreover, the EP/25% PA-DAD composite resulted in well-preserved mechanical properties, especially enhanced toughness, compared with the neat EP. The strategies in our work provided a facile, green, and highly efficient way for fabricating high fire-retardant EP composites.

Gangliogliomas are uncommon intracranial tumors that include neoplastic and abnormal ganglion cells, and show positive immunohistochemical staining for GFAP and syn. This type of lesion occurs more frequently in the temporal lobe than in other areas; they are extremely rare in the suprasellar region. To the best of our knowledge, including our case, 19 cases of GGs have been found in the suprasellar region. Among them, five tumors invaded the optic nerve, nine tumors invaded the optic chiasm, one tumor invaded the optic tract, and two tumors invaded the entire optic chiasmal hypothalamic pathway. In the present study, we describe the first case of suprasellar GGs arising from the third ventricle floor that was removed through the endoscopic endonasal approach. In addition, we summarize the clinical characteristics of GGs, such as age of onset, gender distribution, MRI signs, main clinical symptoms, and treatment methods for GG cases.

Abstract Flame retardants are currently used in a wide range of industry sectors for saving lives and property by mitigating fire hazards. The growing fire safety requirements for materials boost an escalating demand for consumption of fire retardants. This has significantly driven both the industry and scientific community to pursue sustainable fire retardants, but what makes a sustainable flame retardant? Here an overview of recent advances in sustainable flame retardants is offered, and their renewable raw materials, green synthesis and life cycle assessments are highlighted. A discussion on key challenges that hinder the innovation of fire retardants and design principles for creating truly sustainable yet cost‐effective fire retardants are also presented. This short work is expected to help drive the development of sustainable, cost‐effective fire retardants, and expedite the creation of a more sustainable and safer society.

Abstract High energy and power density alkali‐ion (i.e., Li+, Na+, and K+) batteries (AIBs), especially lithium‐ion batteries (LIBs), are being ubiquitously used for both large‐ and small‐scale energy storage, and powering electric vehicles and electronics. However, the increasing LIB‐triggered fires due to thermal runaways have continued to cause significant injuries and casualties as well as enormous economic losses. For this reason, to date, great efforts have been made to create reliable fire‐safe AIBs through advanced materials design, thermal management, and fire safety characterization. In this review, the recent progress is highlighted in the battery design for better thermal stability and electrochemical performance, and state‐of‐the‐art fire safety evaluation methods. The key challenges are also presented associated with the existing materials design, thermal management, and fire safety evaluation of AIBs. Future research opportunities are also proposed for the creation of next‐generation fire‐safe batteries to ensure their reliability in practical applications.

Abstract Polymeric materials are ubiquitously utilized in modern society and continuously improve quality of life. Unfortunately, most of them suffer from intrinsic flammability, significantly limiting their practical applications. Fundamentally, free‐radical reaction is a critical “trigger” for their thermal pyrolysis and following combustion process regardless of the anaerobic thermal pyrolysis in the condensed phase or aerobic combustion of polymers in the gaseous phase. The addition of free radical scavengers represents a promising and effective means to enhance the fire safety of polymeric materials. This review aims to offer a state‐of‐the‐art overview on the creation of fire‐retardant polymeric nanocomposites by adding fire retardants with an ability to trap free radicals. Their specific modes of action (condensed‐phase action, gaseous‐phase action, and dual‐phases action) and performances in some typical polymers are reviewed and discussed in detail. Following this, some key challenges associated with these free‐radical capturers are discussed, and design strategies are also proposed. This review provides some insights into the modes of action of free radical capturing agents and paves the avenue for the design of advanced fire‐retardant polymeric nanocomposites for expanded real‐world applications in industries.

Abstract Advanced elastomers are increasingly used in emerging areas, for example, flexible electronics and devices, and these real‐world applications often require elastomers to be stretchable, tough and fire safe. However, to date there are few successes in achieving such a performance portfolio due to their different governing mechanisms. Herein, a stretchable, supertough, and self‐extinguishing polyurethane elastomers by introducing dynamic π–π stacking motifs and phosphorus‐containing moieties are reported. The resultant elastomer shows a large break strain of ≈2260% and a record‐high toughness (ca. 460 MJ m−3), which arises from its dynamic microphase‐separated microstructure resulting in increased entropic elasticity, and strain‐hardening at large strains. The elastomer also exhibits a self‐extinguishing ability thanks to the presence of both phosphorus‐containing units and π–π stacking interactions. Its promising applications as a reliable yet recyclable substrate for strain sensors are demonstrated. The work will help to expedite next‐generation sustainable advanced elastomers for flexible electronics and devices applications.

Abstract Smart fire alarm sensor (FAS) materials with mechanically robust, excellent flame retardancy as well as ultra-sensitive temperature-responsive capability are highly attractive platforms for fire safety application. However, most reported FAS materials can hardly provide sensitive, continuous and reliable alarm signal output due to their undesirable temperature-responsive, flame-resistant and mechanical performances. To overcome these hurdles, herein, we utilize the multi-amino molecule, named HCPA, that can serve as triple-roles including cross-linker, fire retardant and reducing agent for decorating graphene oxide (GO) sheets and obtaining the GO/HCPA hybrid networks. Benefiting from the formation of multi-interactions in hybrid network, the optimized GO/HCPA network exhibits significant increment in mechanical strength, e.g., tensile strength and toughness increase of ~ 2.3 and ~ 5.7 times, respectively, compared to the control one. More importantly, based on P and N doping and promoting thermal reduction effect on GO network, the excellent flame retardancy (withstanding ~ 1200 °C flame attack), ultra-fast fire alarm response time (~ 0.6 s) and ultra-long alarming period (> 600 s) are obtained, representing the best comprehensive performance of GO-based FAS counterparts. Furthermore, based on GO/HCPA network, the fireproof coating is constructed and applied in polymer foam and exhibited exceptional fire shielding performance. This work provides a new idea for designing and fabricating desirable FAS materials and fireproof coatings.

Waste heat management holds great promise to create a sustainable and energy-efficient society as well as contributes to the alleviation of global warming. Harvesting and converting this waste heat in order to improve the efficiency is a major challenge. Here we report biomimetic nacre-like hydroxyl-functionalized boron nitride (BN)-polyimide (PI) nanocomposite membranes as efficient 2D in-plane heat conductor to dissipate and convert waste heat at high temperature. The hierarchically layered nanostructured membrane with oriented BN nanosheets gives rise to a very large anisotropy in heat transport properties, with a high in-plane thermal conductivity (TC) of 51 W m−1 K−1 at a temperature of ∼300 °C, 7314% higher than that of the pure polymer. The membrane also exhibits superior thermal stability and fire resistance, enabling its workability in a hot environment. In addition to cooling conventional exothermic electronics, the large TC enables the membrane as a thin and 2D anisotropic heat sink to generate a large temperature gradient in a thermoelectric module (ΔT = 23 °C) through effective heat diffusion on the cold side under 220 °C heating. The waste heat under high temperature is therefore efficiently harvested and converted to power electronics, thus saving more thermal energy by largely decreasing consumption.

Summary: Flexible pressure sensors capable of transducing pressure stimuli into electrical signals have drawn extensive attention owing to their potential applications for human-machine interaction and healthcare monitoring. To meet these application demands, engineering microstructures in the pressure sensors are an efficient way to improve key sensing performances, such as sensitivity, linear sensing range, response time, hysteresis, and durability. In this review, we provide an overview of the recent advances in the fabrication and application of high-performance flexible pressure sensors via engineering microstructures. The implementation mechanisms and fabrication strategies of microstructures including micropatterned, porous, fiber-network, and multiple microstructures are systematically summarized. The applications of flexible pressure sensors with microstructures in the fields of wearable human-machine interaction, and ex vivo and in vivo healthcare monitoring are comprehensively discussed. Finally, the outlook and challenges in the future improvement of flexible pressure sensors toward practical applications are presented.

Summary: Extreme flammability of polylactide (PLA) has restricted its real-world applications. Traditional research only focuses on developing new effective fire retardants for PLA without considering the effect of melt viscosity on its fire performances. To fill the knowledge gap, a series of PLA matrices of varied melt flow index (MFI) with and without fire retardants are chosen to examine how melt viscosity affects its fire performances. Our results show that the MFI has a governing impact on fire performances of pure PLA and its fire-retardant systems if the samples are placed vertically during fire testing. PLA with higher MFI values achieves higher limiting oxygen index (LOI) values, and a lower loading level of fire retardants is required for PLA to pass a UL-94 V-0 rating. This work unveils the correlation between melt viscosity and their fire performance and offers a practical guidance for creating flame retardant PLA to extend its applications.

Wooden structures in China’s ancient buildings hold highly historical and cultural values. There is an urgent need to repair and replace the damaged wooden structures after hundreds and thousands of years of exposure to weather. Unfortunately, to date there is still a lack of insightful understanding on how the chemical structure, composition, and micro-morphology evolve over the long-term natural aging before artificial ancient timbers can be developed. This work aims to systematically examine the outer surface, middle layer, and inner surface of the same piece of Chinese fir (Cunninghamia lanceolate) collected from an ancient Chinese building. Based on qualitative and quantitative analysis, both cellulose and hemicellulose in aged woods are found to experience significant degrees of degradation. The crystalline regions of cellulose are also determined to undergo moderate degradation as compared to the control fresh wood. In comparison, the lignin basically remains unchanged and its content in the inner layer slightly increases, as evidenced by more free phenol groups determined. Relative to the outer and inner layer, the middle layer of the ancient wood shows the lowest degree of degradation close to that of the fresh wood. This work offers guidelines for fabricating artificial ancient woods to repair the destroyed ones in China’s ancient architectures.

Construction of electrochemically stable positive materials is still a key challenge to accomplish high rate performance and long cycling life of asymmetric supercapacitors (ASCs). Herein, a novel cobalt–zinc mixed oxide/hydroxide (CoZn-MOH) hierarchical porous film electrode was facilely fabricated based on a cobalt–zinc-based metal–organic framework for excellent utilization in ASC. The as-constructed hierarchical porous film supported on conductive Ni foam possesses a rough surface and abundant macropores and mesopores, which allow fast electron transport, better exposure of electrochemically active sites, and facile electrolyte access and ion diffusion. Owing to these structural merits in collaboration, the CoZn-MOH electrode prepared with a zinc feeding ratio up to 45% at 110 min of heating time (CoZn-MOH-45-110) exhibited a high specific capacitance of 380.4 F·g−1, remarkable rate capability (83.6% retention after 20-fold current increase), and outstanding cycling performances (96.5% retention after 10,000 cycles), which exceed the performances of similar active electrodes. Moreover, an ASC based on this CoZn-MOH-45-110 electrode exhibited a high specific capacitance of 158.8 F·g−1, an impressive energy density of 45.8 Wh·kg−1, superior rate capability (83.1% retention after 50-fold current increase), and satisfactory cycling stability (87.9% capacitance retention after 12,000 cycles).