•A flexible, superhydrophobic and conductive nanofiber composite was prepared.•The nanofiber composite exhibited excellent durability and corrosion resistance.•The nanofiber composite could be used ...for wearable strain sensors.•The sensing performance could be maintained after cyclic abrasion and stretching.
Conductive polymer composite based strain sensors have promising applications in the fields of artificial skin, wearable health-care device, etc. However, fabrication of strain sensors with good stretchability, anti-corrosion, excellent durability and reliability remains challenging. In this work, a superhydrophobic strain sensor based on conductive thermoplastic polyurethane/carbon nanotubes/polydimethylsiloxane (TPU/CNTs/PDMS) was prepared by ultrasonication induced CNTs decoration onto the electrospun TPU nanofiber surface, followed by the PDMS modification. Uniformly dispersed CNTs on the nanofiber surface with a hierarchical structure construct the conductive network. The PDMS layer with a low surface energy endows the nanofiber composite with superhydrophobicity thus anti-corrosion property. The introduction of CNTs/PDMS improves both the Young's modulus, tensile strength and the elongation at break. The superhydrophobicity and conductivity can be maintained after the cyclic stretching-releasing test, displaying excellent durability. When used as a wearable strain sensor, the nanofiber composite is capable of detecting body motion and could work even under harsh conditions (moisture, acid and alkaline environment), showing promising application in wearable electronics.
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•Flexible and superhydrophobic PDMS/CNFs/PDMS foam composites are prepared.•The foam composite possesses excellent corrosion resistance.•The foam composite possesses excellent ...photothermal effect.•The foam composite can separate oil from the emulsion.•The foam composite can achieve high efficiency clean up of crude oil.
Oil spill has now been a serious environmental issue, threatening the aquatic ecosystems and even human living environment. It is still challenging to develop absorbents for efficient oil/water emulsion separation and clean-up of viscous crude oil. Here, we propose a facile method to fabricate flexible and superhydrophobic foam composites for high efficiency oil/water separation under different complex environment. Carbon nanofibers (CNFs) with a hollow structure are decorated uniformly onto the skeleton of the polydimethylsiloxane (PDMS) foam with a strong interfacial adhesion. CNFs could not only enhance the surface roughness and thus the hydrophobicity but also be served as numerous capillary tubes, improving the oil adsorption and oil/water separation performance. More importantly, the CNFs network with a strong light absorption endows the foam with superior photo-thermal conversion capability. The obtained foam composite possesses excellent corrosion resistance and can adsorb various kinds of oil with different densities. The foam composite is able to separate the oil from the emulsion with a relatively high separation efficiency. The material surface temperature is able to quickly increase under the light irradiation, which can significantly reduce the oil viscosity and hence achieve the rapid clean-up of the crude oil floating on water surface.
•A bio-inspired flexible and superhydrophobic fabric is prepared for electromagnetic interference shielding.•The conductivity of the composite fabric could reach 4000 S/m.•The composite fabric ...possesses a high specific shielding effectiveness of 209.6 dB cm3 g−1.•The excellent EMI shielding performance could be maintained after multiple abrasion and cyclic bending tests.
Electromagnetic pollution often causes disturbances to nearby electronic apparatus and also severely threatens people’s health, and it is therefore urgent to develop electromagnetic interference (EMI) shielding materials. However, preparation of EMI shielding materials with lightweight, good flexibility, superior corrosion-resistance, excellent EMI shielding performance remains challenging. Here, a facile method is proposed to prepare flexible, superhydrophobic and highly conductive polymer composite fabrics for the EMI shielding. The polydopamine (PDA) is first decorated onto the fabric surface, and the functional groups in the PDA could promote the Ag precursor adsorption. The electrically conductive PP fabric becomes superhydrophobic and anti-corrosive after further treatment with a fluorine containing molecule. The average shielding effectiveness (SE) and specific SE (SSE) of the composite fabric could reach as high as 48.2 dB and 209.56 dB cm3 g−1 at the frequency of 8.2–12.4 GHz, respectively, which could even be maintained after the composite fabric undergoes cyclic abrasion and bending tests. Furthermore, the superhydrophobic surface ensures the reliability of the conductive fabric as shielding materials when they are used in harsh conditions.
•PVDF/SiO2 microsphere with a hierarchical micro/nano structure was prepared.•The sliding angle for the super-hydrophobic coating was close to zero degree.•The super-hydrophobic coating possessed a ...good self-cleaning performance, water jet stability and corrosion resistance.•The superhydrophobic coating could be used to separate the oil with the salt, acid and alkali solution.•The flexible PVDF/SiO2 membrane had a high oil water separation efficiency.
Super-hydrophobic materials have recently attracted great interest from both academia and industry, due to their promising applications in self-cleaning, oil-water separation, etc. Here, we developed a facile one step method to prepare the hybrid polyvinylidene fluoride (PVDF)/SiO2 microspheres based on electro-spraying for super-hydrophobic coating. By controlling nanoparticle concentration, the SiO2 could be uniformly distributed on PVDF microsphere surface, forming a hierarchical micro/nano structure. The contact angle (CA) of the super-hydrophobic coating could reach as high as 162°, and the sliding angle (SA) could be close to zero degree. The super-hydrophobic coating possessed a good self-cleaning performance, water jet stability and corrosion resistance. It was found that gravity driven oil-water separation was achieved by using the filter paper coated with the super-hydrophobic hybrid microspheres. More importantly, the coated filter paper could not only separate the oil with the pure water but also the corrosive solution including the salt, acid and alkali solution. With the increase of the solution concentration, the free-standing membrane composed of the hybrid microspheres and ultrathin threads were obtained, and the membrane showed a high flux and efficiency for oil-water separation. In addition, the flexible membrane could be used for adsorption of different kinds of oil.
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The synergistic conductive network was constructed by incorporation of 1D carbon nanotube (CNT) or 0D acetylene black (ACET) in epoxy/nickel-coated carbon fiber (EP/NCCF) blend foams, ...and the influence of carbon nanofiller dimension on the electromagnetic interference (EMI) shielding performance of polymer/metal conductive foams was systematically investigated. Adding ACET into EP/NCCF foams improved the EMI SE merely by the enhancement in the conductivity, while mixing 1D CNTs with NCCFs built a multiple scale carbon-metal shielding network in EP foams. Due to the remarkable synergistic effect of the microwaves reflection from NCCF network and microwaves absorption from CNT network, the carbon-metal network exhibited a strong microwave attenuation. The EP/NCCF/CNT foam with only 2.35 vol% hybrid fillers showed an EMI SE of 40.8 dB, which was twice that of the EP/NCCF/ACET foam. The construction of the carbon-metal synergistic network opens a new avenue to design and prepare highly efficient EMI shielding composites materials.
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Oil spill and oily wastewater have now become a serious threat to the freshwater and marine environments. Porous materials with super-hydrophobicity and super-oleophilicity are good ...candidates for the oil adsorption and oil/water separation. Here, flexible hybrid nanofibrous membrane (FHNM) containing SiO2/polyvinylidene fluoride (PVDF) microspheres was prepared by simultaneous electrospinning and electrospraying. The obtained FHNM combined the flexibility of the nanofiber mat and super-hydrophobicity of the microspheres, which could not be achieved by either only electrospinning or only electrospraying. It was found that when the weight ratio between the SiO2 and PVDF reached a critical value, the SiO2 nanoparticles were present on the PVDF microsphere surface, significantly improving the surface roughness and hence the contact angle of the FHNM. Compared with the pure electrospun PVDF nanofiber mat, most of the FHNMs have a higher oil adsorption capacity. The FHNM could separate the oil with water quickly under the gravity and displayed a high efficiency and good reusability for the oil/water separation. More importantly, the FHNM could not only separate the oil with the pure water but also the corrosive solution including the salt, acid and alkali solution.
Electrically conductive polymer composites (CPCs) have been applied extensively in many fields such as electronics, wearable sensors and antistatic agent. It is still challenging to develop CPCs with ...a low percolation threshold and high electrical conductivity. Here, highly electrically conductive polystyrene (PS) composite with a fiber-based segregated structure is prepared by carbon nanotubes (CNTs) decoration onto the electrospun PS fibers, followed by hot press at a proper temperature. In the electrically conductive PS composite, the CNTs are segregated at the interface among the fiber-shaped matrix, and the one-dimensional fiber possessing the merit of a large aspect ratio, which facilitates the formation of conductive network. The percolation threshold is calculated to be 0.084 vol%, and the electrical conductivity of the CPC reaches 83.3 S/m when the concentration of the CNTs is 1.5 vol%. If the hot press temperature is much higher than the glass transition temperature of PS, the fiber-based segregated structure would be destroyed, increasing the percolation threshold while decreasing the conductivity of the composite. The fiber-based segregated structure provides a new and versatile route for the rational design and preparation of CPCs with a low percolation threshold and high conductivity.
We have developed a kind of high-yield synthesis strategy for silver nanowires by a two-step injection polyol method. Silver nanowires and polyethylene oxide (PEO) (M w = 900 000) were prepared in a ...homogeneous-coating ink. Wet composite films with different thicknesses were fabricated on a PET substrate by drawn-down rod-coating technology. Silver nanowires on PET substrates present a homogeneous distribution under the assistance of PEO. Then PEO was thermally removed in situ at a relatively low temperature attributed to its special thermal behavior under atmospheric conditions. As-prepared metallic nanowire films on PET substrates show excellent stability and a good combination of conductivity and light transmission. A layer of transparent poly(ethersulfones) (PESs) was further coated on silver nanowire networks by the same coating method to prevent the shedding and corrosion of silver nanowires. Sandwich-structured flexible transparent films were obtained and displayed excellent electromagnetic interference (EMI) shielding effectiveness.
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•A flexible and conductive nanofiber composite membrane with superhydrophobicity and superoleophilicity was prepared.•The contact angle (CA) and the electrical conductivity could ...reach as high as 152° and 7.6Sm−1 respectively.•The superhydrophobicity and electrical conductivity could be maintained during the cyclic stretching.•The superhydrophobic composite membrane could be used to separate the oil with the salt, acid and alkali solution.•The superhydrophobic composite membrane exhibited a large flux, high separation efficiency and superior recyclability.
A flexible, stretchable and electrically conductive nanofiber composite with superhydrophobicity was fabricated by ultrasonication induced carbon nanotubes (CNTs) decoration onto the polymer nanofiber, followed by methyltrichlorosilane (MTS) modification. The introduction of CNTs and polysiloxane derived from MTS improved the superhydrophobicity, conductivity, thermal stability and mechanical properties of the nanofibrous membrane. The superhydrophobicity and electrical conductivity could be maintained during the cyclic stretching. The nanofiber composite membrane could be utilized to separate the oil from the oil/water mixture regardless of pH of water, exhibiting a large flux, high efficiency and good recyclability.
Zinc oxide (ZnO) has attracted much attention for various applications because of its unique electrical, optical, magnetic and piezoelectric properties. ZnO nanowires (NWs) are often grown onto the ...carbon fiber (CF) surface to improve the electrical conductivity and flexibility of ZnO, and it is important to understand and further enhance the interaction between ZnO NWs and CFs. Herein, ZnO NWs were grown onto carbon fabrics through a facile hydrothermal method, and the pull-off force to detach an individual ZnO nanowire from CF was measured using a nano-manipulator inside a scanning electron microscope chamber. Also, a novel dopamine-based functionalization method was developed to improve the interfacial adhesion between ZnO NWs and CFs. It was found that introducing polydopamine (PDA) on CF could increase significantly the adhesion strength between CF and ZnO NW and their interfacial shear strength with epoxy as measured by the single fiber microbond test. The hierarchical ZnO NWs on CF fabrics were then utilized to fabricate the laminates. The highest mode I and mode II interlaminar toughness were obtained in those laminates comprising CF/PDA/ZnO NWs owing to the high chemical bonding between ZnO NWs and PDA modified CF surface and strong mechanical interlocking between ZnO NWs and epoxy.
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