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•A skin-inspired thermoelectric nanocoating was constructed.•The nanocoating exhibited accurate temperature sensing at 100–300 ℃.•The nanocoating exhibited sensitive and repeatable ...fire-warning capability.•The nanocoating significantly improved the flame retardancy of many combustible materials.
Temperature sensing enables flammable materials to respond intelligently at high temperature, which is conducive to further improving their fire safety. However, it is still challenging to develop a smart nanocoating with sensitive temperature-sensing and efficient flame retardancy. Inspired by human skin, a thermoelectric flame retardant (TE-FR) nanocoating was fabricated by combining a dermis-mimicking thermoelectric (TE) layer and an epidermis-mimicking flame retardant (FR) layer. The TE-FR nanocoating exhibited accurate temperature sensing at 100–300 ℃ and repeatable fire-warning capability. When being burned, the fire-warning response time of the TE-FR nanocoating was only 2.0 s, and it retriggered the fire-warning device within 2.8 s when it was reburned. Meanwhile, the TE-FR nanocoating exhibited outstanding flame retardancy. The coated polypropylene self-extinguished in the horizontal and vertical burning tests. Besides, its peak heat release rate, total heat release, and peak smoke production rate were significantly reduced. This work proposed an ingenious strategy to fabricate smart nanocoating for temperature sensing and fire safety, which revealed an enticing prospect in the fields of fire protection, electronic skin, and temperature monitor.
Nanofibrous membranes with superwetting performance have promising applications in oil adsorption or oil/water separation. However, the development of superwettable, stretchable and durable nanofiber ...composite for efficient separation of oil-in-water emulsion is still a challenge. Herein, a simple and versatile method was proposed to prepare flexible, superhydrophilic and electrically conductive polymer nanofiber composite with a core/shell structure by acidified carbon nanotubes (ACNTs) decoration onto polyurethane (PU) nanofibers and subsequent polydopamine (PDA) modification. Multiple interfacial hydrogen bonding among ACNTs, PDA and PU nanofibers results in the enhancement of both the tensile strength and Young's modulus of the PU nanofibrous membrane and also ensures the excellent stretchability, surface stability and durability of the nanofiber composite. The obtained superhydrophilic/underwater superoleophobic nanofiber composite exhibits superior anti-fouling property and can be used for high efficiency separation of oil-in-water (even corrosive) emulsion with outstanding recyclability. The flexible and multifunctional nanofiber composite with a unique PDA/ACNTs shell and polymer nanofiber core structure shows great potentials in practical oily wastewater purification.
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•A flexible, electrically conductive and superhydrophilic/underwater superoleophobic nanofiber composite was prepared.•The introduction of ACNTs and PDA greatly improves the mechanical properties of the PU nanofibrous membrane.•The nanofiber composite exhibits excellent surface stability and durability.•The composite membrane is able to achieve high efficient separation of the oil from emulsions.•The nanofiber composite membrane exhibits a large flux, high separation efficiency and superior recyclability.
Solar desalination via interfacial evaporation is an effective, green and convenient method to solve the shortage of fresh water. It remains challenging to develop high quality light absorber ...materials that can both reduce the heat loss and avoid salt accumulation during the seawater evaporation and be also used in different harsh conditions. Here, we, for the first time, propose an emulsion dip-coating strategy to fabricate a superhydrophobic fabric composite for high-efficiency interfacial evaporation. During the dip-coating in the oil-in-water emulsion, MXene in the water phase together with the polydimethylsiloxane in the oil phase is decorated onto the polydopamine modified elastic fabric through the interfacial hydrogen bonding. The obtained superhydrophobic/superoleophilic fabric composite is able to separate the oil from the polluted seawater. Air bubbles are trapped between the fabric and water, reducing the heat conduction to bulk water. Furthermore, the salt is prevented from accumulation on the fabric surface even in a very high salinity condition. The solar interfacial evaporation rate and efficiency reach 1.526 kg m−2 h−1 and 93.3% under 1 sun, respectively, and can be almost maintained after a long-time use. This study provides a new avenue to prepare multifunctional light absorbers for efficiency solar desalination and oil-water separation.
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•An emulsion dipping method is developed to prepare superhydrophobic MXene based fabric.•The superhydrophobic fabric is able to separate the oil from the polluted seawater.•The superhydrophobicity makes the evaporator salt-resistant.•The superhydrophobic fabric evaporator can reach highly efficient solar desalination.
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•The aerogel achieved a hitherto shortest fire-warning response time (~0.25 s).•The aerogel self-extinguished and exhibited excellent flame retardancy.•The aerogel could resist a ...1200 °C flame, showing outstanding thermal insulation.•The aerogel was endowed with good piezoresistivity.
High fire-safe aerogel with multi-functionality is urgently desirable due to the frequent fire disasters. However, it is still a challenge to afford both excellent flame retardancy and sensitive fire-warning in combustible aerogels. Herein, we fabricated an ultrasensitive fire-warning and high fire-resistance chitosan/montmorillonite/carbon nanotube composite aerogel (CCA) via freeze-drying. Benefiting from the rapid decrease of the electrical resistance for amino-functionalized carbon nanotube when being burned, CCA achieved a hitherto shortest fire-warning response time (~0.25 s). Importantly, the aerogel exhibited excellent flame retardancy and self-extinguished in the vertical burning test. Besides, owing to the hierarchical porous structure of the aerogel and the excellent barrier effect of the montmorillonite nanosheet, CCA could resist a high-temperature flame up to 1200 °C and effectively prevent the temperature of the nonexposed side from increasing, exhibiting excellent thermal insulation. Furthermore, the mechanical resilience, anti-fatigue performance, electrical conductivity, and unique three-dimensional network endowed the aerogel with good piezoresistivity. This work provides a facile, environmentally-friendly, and cost-effective approach to fabricating multifunctional fire-safe aerogel, showing promising applications in exterior wall insulation, vehicle interior, firefighting, and wearable electronics.
•A superhydrophobic and multi-responsive fabric composite was prepared.•The EMI shielding performance could reach to ~56.1 dB in the X band.•The absorption ratio of electromagnetic waves could ...account for 30%.•The fabric composite exhibited outstanding electro-photo-thermal effect.
Wearable electronics and smart garments have attracted increasing attention due to their potential application in health care monitoring, artificial intelligence, soft robotics, etc. However, designing robust and flexible wearable electronics that can shield electromagnetic waves and work in all-weather environment or even harsh conditions remains a challenge. Herein, superhydrophobic and multi-responsive fabric composites with outstanding electro-photo-thermal effect and excellent electromagnetic interference shielding (EMI) performance are fabricated by decoration of conductive Ag nanoparticles onto the oxygen plasma treated polypropylene (PP) fabric, followed by multiple spray-coating with a mixture of Fe3O4 nanoparticles/polydimethylsiloxane (PDMS). The obtained fabric composites exhibit high conductivity (up to 108.8 S/cm) and the EMI shielding effectiveness (SE) can reach as high as ~56.1 dB in the X band, in which of the incident electromagnetic waves can account for 30%. Moreover, the PDMS coating not only improves the interface adhesion between the nanoparticles and fibers, but also endows the fabric composites with superhydrophobicity, leading to an excellent self-cleaning performance. Surprisingly, the fabric composites also exhibit multiple responsive properties to electron and light, known as electro-photo-thermal effect, which can be maintained during mechanical deformations and cold environment. This work opens a new avenue for next-generation of wearable electronics with multi-functionality.
Interleaf is often used to increase the interlaminar fracture toughness of carbon fiber/epoxy (CF/EP) composites, but it remains a challenge to develop high-performance interleaves that can greatly ...improve the toughness while simultaneously maintaining the in-plane properties. In this study, the carboxylated carbon nanotubes were uniformly decorated onto the surface of electrospun PA66 nanofibers by combination of ultrasonication and interfacial hydrogen bonding, and the obtained flexible nanofiber composite was served as interleaves in the CF/EP laminate. It is found that the modes I and II interlaminar fracture toughness of CNT-COOH/PA66 nanofiber interleaved laminate increases by 122 and 81% compared to the pristine CF/EP. Also, the flexural strength and flexural modulus was enhanced due to the reinforcing effect of the CNT-COOHs. The toughening mechanisms for both modes I and II fracture are investigated in detail based on the morphology of the delamination surface of the laminates.
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•Bionic PEDOT: PSS-Cu2+ fibers with fluff-like array are prepared in large scale.•The synergistic effect of phase separation and self-assembly is approached.•Fluff-like array endows ...bionic fibers with enhanced pressure sensing capability.•The bionic fibers are further employed for wearable airflow sensor.
Wearable sensors based on fibers or textiles are attracting widespread attention due to their potential applications in wearable health monitoring and care systems, where high sensitivity plays an essential role in the development of electroconductive fibers. Though the great progress has been made in designing novel structures and understanding sensing mechanism, how to prepare conductive fibers with high sustainability and conductivity via a facile and efficient method is still a challenge. Herein, inspired by the spider’s fluff, an ion-induced self-assembly is proposed and performed to obtain continuous and large-scale fabrication of poly (3, 4-ethylenedioxythiophene): poly (styrene sulfonate) (PEDOT: PSS) fibers with an array microstructure. The formation of copper complex with fluff-like shape occurs spontaneously on the surface of PEDOT fibers without any additional post-treatment or harsh condition, which is difficult to achieve by other approaches. Benefiting from the fluff-like array, these biomimetic PEDOT: PSS-Cu2+ fibers possess a near 5-fold increase in specific surface area compared to that of pristine PEDOT: PSS fibers, which endows it with a good pressure sensitivity with ultralow detection limit (~82 Pa) and fast response time (47 ms). We further demonstrate their potential applications for airflow detection, real-time information transmission, and gravity/pressure sensing while decorating such biomimetic fibers to braided fabrics. More importantly, this work sheds light on the formation mechanisms of microstructures on the fiber, inspiring a unique path for conventional wet-spinning technology and novel fiber-surface design in order to achieve its outstanding sensitivity.
•Conductive sponge composite with lotus leaf inspired microstructure is prepared.•The sponge composite shows excellent anticorrosion and temperature insensitive properties.•The sponge composite ...possesses ultrahigh compressibility and linear working strain range.•The sponge composite shows potential usage in body motion detection.
Piezoresistive sensors have promising applications in wearable electronics; however, developing multi-functional piezoresistive sensors that possess ultrahigh compressibility and linear working range and could be used in tough environment (e.g., high humidity, corrosive media and low temperatures) remains a challenge. Herein, a flexible electrically conductive polymer foam composite (CPFC) with the lotus leaf inspired microstructure is prepared by anchoring carbon nanotubes (CNTs) onto the skeleton of the polymer foam with the assistance of ultrasonication and simultaneous non-solvent induced phase separation (NIPS). Hemisphere arrays are produced on the skeleton of the polymer foam, while CNTs are decorated on the surface of these arrays, forming conductive network. The obtained superhydrophobic CPFC exhibits excellent anti-corrosive and photothermal conversion performance, making it possible to be used in some harsh environment. When used as the piezoresistive sensor, the CPFC exhibits stable electrical conductivity, extremely high compressibility and linear working range (up to 90%), superb sensing stability and durability (over 2300 cycles). Furthermore, the piezoresistive sensing performance is impervious to the ambient temperature, and the CPFC sensor can work in the temperature from −20 ℃~80 ℃ with stable sensing signals. Also, the CPFC can detect various human body movements even in the corrosive condition.
The utilization of solar energy for water evaporation to obtain fresh water shows potential applications in addressing water scarcity issues. It remains great challenges to develop light absorber ...materials with high photo-thermal conversion efficiency, large specific surface area and excellent corrosion resistance. Here, we demonstrate a hierarchically mesoporous and superhydrophilic carbon nanofiber membrane (CNF) based on the sublimation of the terephthalic acid from the polyacrylonitrile nanofibers during the calcination. The porous structure enhances the light absorption (94.2% in a broadband from 280 to 2500 nm). Furthermore, the mesopores in the individual CNF as well as the macropores in the membrane could not only significantly improve the interfacial evaporation area and the hydrophilicity but also reduce the thermal conductivity and hence the thermal lose. The porous membrane with hydrophilicity possesses good salt rejection performance. When used for interfacial solar water evaporation, the CNF membrane exhibits a high solar energy efficiency and evaporation rate of 89.5% and 1.36 kg m−2 h−1 under one sun illumination, respectively. In addition, the superhydrophilic CNF membrane with excellent corrosive resistance can even be used for solar desalination of sea water containing acid or alkali and also the oil-in-saline water emulsions.
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•A hierarchically macro/meso porous carbon nanofiber (CNF) membrane was prepared.•High surface roughness and heteroatom doping contribute to the superhydrophilicity.•The CNF membrane has a high sunlight absorption and a low thermal conductivity.•A high interfacial solar evaporation rate is achieved.•Solar desalination can be conducted even in acid/alkali conditions.
Superhydrophobic coatings have wide applications in many fields. However, superhydrophobic and smart coatings with multifunctionality and their applications in flexible sensing electronics are seldom ...reported. In this work, durable, superhydrophobic, and anticorrosive coatings with excellent Joule heating and electromagnetic interference (EMI) shielding performance are prepared on the basis of Ag precursor reduction and synchronous nonsolvent induced phase separation. Silver nanoparticles (AgNPs) coated with the copolymer (polystyrene-block-poly(ethylene-co-butylene)-block-polystyrene: SEBS) are uniformly distributed on the target substrate, forming mechanically durable conductive network. SEBS could not only endow the surface coating with superhydrophobicity but also improve the interaction among individual Ag nanoparticles and the interfacial adhesion between AgNPs and the substrate. The multifunctional coating possesses excellent anticorrosive, self-cleaning, and deicing properties. The high conductivity endows the coatings with excellent Joule heating and EMI shielding performance. The multifunctional coating can be applied to a variety of different substrates with outstanding surface stability and reliability. The conductivity for the smart coating can reach as high as 107 S/cm with the EMI shielding effectiveness up to 37.8 dB. At a low applied voltage of 1 V, the conductive fabric can be heated up to over 80 °C in 60 s and displays good recyclability during dozens of heating and cooling cycles. The Joule heating-induced temperature increase could be used for efficient surface deicing. When used for the flexible and wearable strain sensors, the multifunctional coating has a very low strain detection limit of 0.5% and large sensitivity (with the gauge factor as high as 1075) and excellent repeatability. In addition, it can be used for precisely monitoring different body motions, including both large and subtle joint movement.
