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Severe environmental pollution resulting from improper emissions of volatile organic gases (VOCs) has posed significant menaces to human health, ecosystem security, and the pursuit of socially sustainable development. Herein, we present a convenient approach to crafting conductive gas-sensitive nanocomposites with double-percolation microstructure by employing a blend of thermoplastic polyurethane (TPU) and polycaprolactone (PCL) as the compositing matrix, combined with multi-walled carbon nanotubes (MWCNTs) as the functional nanofiller. The analysis of the interface energy between the components inside the nanocomposites revealed that MWCNTs were preferentially dispersed within the TPU phase. By adjusting the TPU-to-PCL ratio and the adding sequence of components during compositing, a two-phase continuous matrix structure and a double-percolation conductive microstructure were attained, which was benefited to the enhancement of electrical conductivity. When the mass ratio of TPU-to-PCL was fixed at 50:50, the lowest resistivity of the TPU/PCL/MWCNTs nanocomposite, measuring 2.57 × 105Ω·m was achieved when MWCNTs were initially blended with TPU followed by PCL. Gas-sensitive assessments of the TPU/PCL/MWCNTs nanocomposite revealed its exceptional selectivity, responsiveness, and recovery to formaldehyde, surpassing other targeted VOCs such as benzene, xylene, ammonia, and ethanol. Notably, gas responsiveness to formaldehyde at 25 °C and 500 ppm registers at 74% for the TPU/PCL/MWCNTs nanocomposites. Furthermore, responsiveness exhibits a robust linear correlation with increasing formaldehyde concentration. [ABSTRACT FROM AUTHOR]

In this study, multiwalled carbon nanotubes (MWCNTs) were incorporated into vulcanized natural rubber (VNR) matrixes to create nanocomposites with improved mechanical, thermal, and electrical properties. The interfacial interaction of the MWCNTs with the VNR matrix was quantitatively evaluated based on the crosslink density value calculated using the Flory–Rehner methodology. Various rheometric parameters were influenced by the addition of the MWCNTs, including minimum torque (ML), maximum torque (MH), and scorch time (tS1). The MWCNTs significantly enhanced the vulcanization of the composites based on the VNR matrix. This study highlights the impact of MWCNTs on crosslink density, improving mechanical properties and reducing swelling in the VNR matrix. We discovered that the MWCNTs and the VNR matrix interact strongly, which improved the mechanical properties of the matrix. The MWCNTs improved the hardness, tensile strength, and abrasion resistance of the VNR/MWCNT nanocomposites. Based on dynamic mechanical analysis, MWCNT incorporation improved stiffness as indicated by a change in storage modulus and glass transition temperatures. The addition of MWCNTs to the VNR/MWCNT nanocomposites significantly improved their electrical properties, reaching a percolation threshold where conductive pathways were formed, enhancing their overall conductivity. Overall, this study demonstrates the versatility and functionality of VNR/MWCNT nanocomposites for a variety of applications, including sensors, electromagnetic shielding, and antistatic blankets. [ABSTRACT FROM AUTHOR]

Highlights Nanocomposite/hydrogel hybrid electrodes are created with high interfacial toughness by introducing soft microfoams as the mechanically interlocking layer. In the hybrid electrodes, silver nanowires and hydrogels are electrically connected through the porous microfoams, achieving high conductivity and low contact impedance for high-quality biopotential recordings. The microfoam-enabled bonding strategy is generally applicable to diverse polymer substrates.

In this study, multiwalled carbon nanotubes (MWCNTs) were incorporated into vulcanized natural rubber (VNR) matrixes to create nanocomposites with improved mechanical, thermal, and electrical properties. The interfacial interaction of the MWCNTs with the VNR matrix was quantitatively evaluated based on the crosslink density value calculated using the Flory–Rehner methodology. Various rheometric parameters were influenced by the addition of the MWCNTs, including minimum torque (ML), maximum torque (MH), and scorch time (tS1). The MWCNTs significantly enhanced the vulcanization of the composites based on the VNR matrix. This study highlights the impact of MWCNTs on crosslink density, improving mechanical properties and reducing swelling in the VNR matrix. We discovered that the MWCNTs and the VNR matrix interact strongly, which improved the mechanical properties of the matrix. The MWCNTs improved the hardness, tensile strength, and abrasion resistance of the VNR/MWCNT nanocomposites. Based on dynamic mechanical analysis, MWCNT incorporation improved stiffness as indicated by a change in storage modulus and glass transition temperatures. The addition of MWCNTs to the VNR/MWCNT nanocomposites significantly improved their electrical properties, reaching a percolation threshold where conductive pathways were formed, enhancing their overall conductivity. Overall, this study demonstrates the versatility and functionality of VNR/MWCNT nanocomposites for a variety of applications, including sensors, electromagnetic shielding, and antistatic blankets.

Continuous monitoring of arterial blood pressure is clinically important for diagnosing and managing cardiovascular diseases. Soft electronic devices with skin‐like properties show promise in various applications, including the human‐machine interface, the Internet of Things, and health monitoring. Herein, the use of add‐on soft electronic interfaces addresses the connection challenges between soft electrodes and rigid data acquisition circuitry for bioimpedance monitoring of cardiac signals, including heart rate and cuffless blood pressure is reported. Nanocomposite films in add‐on electrodes provide robust electrical and mechanical contact with the skin and the rigid circuitry. Bioimpedance sensors composed of add‐on electrodes offer continuous blood pressure monitoring with high accuracy. Specifically, the bioimpedance collected with add‐on nanocomposite electrodes shows a signal‐to‐noise ratio of 37.0 dB, higher than the ratio of 25.9 dB obtained with standard silver/silver chloride (Ag/AgCl) gel electrodes. Although the sample set is low, the continuously measured systolic and diastolic blood pressure offer accuracy of −2.0 ± 6.3 mmHg and −4.3 ± 3.9 mmHg, respectively, confirming the grade A performance based on the IEEE standard. These results show promise in bioimpedance measurements with add‐on soft electrodes for cuffless blood pressure monitoring. [ABSTRACT FROM AUTHOR]

Multifunctional nanocomposite strain sensors, especially those that contain dispersed multiwall carbon nanotubes (MWCNTs), are known to possess exceptional electrical conductivity. These nano-reinforced composites can be used for structural health monitoring. It is with this in mind that we focus our attention on calibrating the electromechanical behaviour of MWCNT-reinforced epoxy nanocomposites both numerically and experimentally. In particular, our main objective is to unravel the coupled electromechanical behaviour of the conducting composite prior to failure. In the numerical effort, we adopted the effective-medium homogenization and Mori-Tanaka method to account for tunnelling resistance and to predict the sensory capability of the newly developed composite. In the experimental effort, a conductive epoxy nanocomposite containing high quality MWCNTs randomly dispersed within liquid neat epoxy system was developed. The conducting domains of the developed nanocomposite were characterized using atomic force microscope (AFM) measurements. Electromechanical characterisation of the MWCNT-reinforced nanocomposites was also performed using controlled uniaxial tensile tests to evaluate its sensory capability against load. The results of our work reveal: (i) excellent agreement with the micromechanical model, and (ii) the dramatic influence of the concentration of the MWCNTs, their agglomeration and aggregation on the sensory sensitivity of the MWCNT-reinforced epoxy nanocomposite. Interestingly, an increase in the MWCNT filler loading led to a decrease in the sensory sensitivity of the nanocomposite as measured by uniaxial strain gauge factor. The work was further extended to highlight the sources of errors that could lead to erroneous results in developing and calibrating electrically conducting pathways in polymer nanocomposites. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Conductive chitin-cellulose loaded with Zn@(0.1, 0.3, 0.5 mol.%) Cu nanocomposites. • Sol-gel-Polymerization techniques used to combine Zn@(0.1, 0.3, 0.5 mol.%) Cu@ CH-CE composite. • Spectroscopic and dielectric properties are investigated for nanocomposites. • Improved Zn@Cu nanoparticles enhance mesostructures, bactericidal activity. In this research, we fabricated a functional conductive nanocomposite with valuable properties through a chitin (CH) and cellulose (CE) polymerization process, incorporating ZnO/(0.1, 0.2, 0.3 mol.%) CuO bioactive nanoparticles. These bioactive nanoparticles, synthesized through sol–gel and polymerization interactions, greatly enhanced the structural, dielectric, and antimicrobial characteristics of CH-CE@ZnO/CuO conductive nanocomposites. The morphological analysis revealed that these nanoparticles, with diameters ranging from 11-25 nm, formed covalent bonds with the membrane matrix, bolstering the conductive nanocomposites ' structural integrity and dielectric performance. The dielectric properties of the conductive nanocomposites were significantly enhanced by the even distribution of ZnO/CuO nanoparticles within the CH-CE composite. Additionally, antimicrobial assessments demonstrated that the CH-CE@ZnO/CuO conductive nanocomposites displayed significant antibacterial properties against the Escherichia coli and Staphylococcus aureus, showcasing their potential as active packaging materials for electronic, biosensors, and sustainable applications. [ABSTRACT FROM AUTHOR]

The present work focuses on the preparation, using a solution process, of flexible conductive nanocomposites based on polyurethane (PU)/polyaniline (PANI) with different mass percentages: 2, 3 and 4%. Because of the low conductivity of the PU + PANI films, these later were doped with inorganic NiCl2. PU + PANI undoped films were synthesized by a "one-shot" process. For doping process, PANI has been doped according to two different methods: The first one consists of the impregnation of the pristine PU + PANI film in a solution of inorganic salt dopant with a solvent (THF) during a soaking time, while the second method uses a "one-shot" process. The structural characterization and conductivity properties of the polymer blends were examined by differential scanning calorimetry, Fourier transform infrared spectroscopy and dielectric measurements spectroscopy. The results show that NiCl2 significatively increases the conductivity compared to pure PU + PANI blends, with better results using the second method of synthesis. [ABSTRACT FROM AUTHOR]

The present work focuses on the preparation, using a solution process, of flexible conductive nanocomposites based on polyurethane (PU)/polyaniline (PANI) with different mass percentages: 2, 3 and 4%. Because of the low conductivity of the PU + PANI films, these later were doped with inorganic NiCl2. PU + PANI undoped films were synthesized by a "one-shot" process. For doping process, PANI has been doped according to two different methods: The first one consists of the impregnation of the pristine PU + PANI film in a solution of inorganic salt dopant with a solvent (THF) during a soaking time, while the second method uses a "one-shot" process. The structural characterization and conductivity properties of the polymer blends were examined by differential scanning calorimetry, Fourier transform infrared spectroscopy and dielectric measurements spectroscopy. The results show that NiCl2 significatively increases the conductivity compared to pure PU + PANI blends, with better results using the second method of synthesis. [ABSTRACT FROM AUTHOR]

Replicating the haptic perception capability of the human hand is an indispensable goal for intelligent robots and human–machine interactions. Multifunctional electronic skin (e‐skin) sensors can be an ideal candidate to bridge the gaps among humans, robots, and the environment. Mutual interference of multistimuli and unconformable spatial distribution impedes the application of e‐skin sensors. Hence, a large‐area, hand‐covering elastomeric e‐skin sensor is proposed to imitate the human hand for multifunctional detection. Five multifunctional sensing units are designed on the fingertips, and 15 pressure‐sensing units are distributed on the finger phalanxes and palm to cover the main sensory area of the hand. A multilayer architecture is designed to improve the sensing performances and reduce the coupling interference during multifunctional detection. The e‐skin sensor exhibits similarity to the human hand not only in shape but also in functionality, possessing pressure sensitivity of 0.025 V kPa−1 in 0.1–120 kPa and temperature sensitivity of 0.38% °C−1 in 20–70 °C. The performance of the e‐skin sensor can meet the requirements of daily manipulations. Experimental studies on grasping objects with different grasping modes and object properties demonstrate the potential applications of the e‐skin sensor for grasping haptic perception and human–robot interactions. [ABSTRACT FROM AUTHOR]

Replicating the haptic perception capability of the human hand is an indispensable goal for intelligent robots and human–machine interactions. Multifunctional electronic skin (e‐skin) sensors can be an ideal candidate to bridge the gaps among humans, robots, and the environment. Mutual interference of multistimuli and unconformable spatial distribution impedes the application of e‐skin sensors. Hence, a large‐area, hand‐covering elastomeric e‐skin sensor is proposed to imitate the human hand for multifunctional detection. Five multifunctional sensing units are designed on the fingertips, and 15 pressure‐sensing units are distributed on the finger phalanxes and palm to cover the main sensory area of the hand. A multilayer architecture is designed to improve the sensing performances and reduce the coupling interference during multifunctional detection. The e‐skin sensor exhibits similarity to the human hand not only in shape but also in functionality, possessing pressure sensitivity of 0.025 V kPa−1 in 0.1–120 kPa and temperature sensitivity of 0.38% °C−1 in 20–70 °C. The performance of the e‐skin sensor can meet the requirements of daily manipulations. Experimental studies on grasping objects with different grasping modes and object properties demonstrate the potential applications of the e‐skin sensor for grasping haptic perception and human–robot interactions.

Elastomer-based nanocomposites(EcNs) were prepared with a novel mixing method to determine the deformation properties under constant amplitude dynamic operating conditions. The fillers of EcNs consists of functionalized(M-FCNTs) and nonfunctionalized carbon-nanotubes(M-NCNTs), graphite(GF) and carbon black(CB). In this study, six different mixtures were prepared using M-FCNT, and M-NCNT fillers in 1, 2, 3 phr ratios, except for a CB-filled reference mixture(C00). Graphite, which has exfoliation and excellent lubricating properties1, was added to six mixtures at the rate of 1 phr to prevent agglomeration of M-CNTs in the mixtures. SEM images show that M-CNTs are homogeneously distributed, interacting strongly with GF, and M-FCNTs have a better interface interaction than M-NCNTs. During crosslinking of M-NCNT filled EcNs, due to the resistance in the direction of the polymer chain's movement, the difference between minimum torque and maximum torque increased by approximately 10% compared to M-FCNTs. The lost energy (ΔW) between the loading and unloading curves of M-NCNT filled EcNs increased compared to the M-FCNT filled mixtures and C00. The resistance properties depending on the samples' strain value showed a more stable and repetitive behavior in M-FCNT filled EcNs with a ratio of 1 and 2 phr, called F-C01 and F-C02, respectively. The semiconductor F-C01 sample showed the most stable behavior due to preserving the conductive filler network's structural order during the fatigue test, although the average resistance change was highest with 1.51E + 07 Ω. We discuss ways to use conductive elastomer composites as an effective deformation detection sensor in dynamic applications based on the results. [ABSTRACT FROM AUTHOR]

In this study a sensitive electrochemical sensor for the detection of E.coli has been developed using silver nanoparticle (Ag) embedded poly (9, 9-dioctylfluorene-ran-phenylene) (CFP) nanocomposite as a conductive platform and DNA hybridization technique. The new polymer was synthesized from 9, 9-dioctylfluorene and 1, 3-dichlorobenzene and biphenyl through Friedel Crafts alkylation reaction and the synthesized polymer as well as the Ag nanoparticles loaded composite were characterized using Fourier-transform infrared spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR), X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) analysis. For accurate and rapid label-free electrochemical detection of pathogenic bacteria such as E.coliwas studied by spin coating the nanocomposite suspension into indium tin oxide electrode (ITO) followed by the immobilization of aminoterminated oligonucleotide (pDNA), as probe. The resultant pDNA/Ag-CFP/ITO biosensor was then used to detect ssDNA, cleaved from genomic DNA of E.coli, using differential pulse voltammetry (DPV) technique. Under optimal experimental conditions, the biosensor could detect ssDNA in a wide linear range from 1 × 10-15 M to 1 × 10-22 M with a lowest detection limit of 1 × 10-22 M. [ABSTRACT FROM AUTHOR]

Flexible all-solid-state supercapacitor has been widely used in various portable and wearable electronics devices. Flexible electrode is an important part in flexible supercapacitors. In this work, we fabricate a self-healing polyaniline–poly (vinyl alcohol) (PANI–PVA) composite hydrogels with excellent mechanical characters, brilliant rate capability, and good electrochemical performance. The synergistic effects offered by flexibility of PVA macromolecular chains, high electrical conductivity of carbon nanotubes, reversible hydrogen bonding between phytic acid and PVA, and pseudocapacitance of PANI give PANI–PVA hydrogels the stated advantages. Based on PANI–PVA composite hydrogel, a flexible all-solid-state supercapacitor was fabricated to further investigate the electrochemical performance and self-healing properties. The fabricated supercapacitor not only delivers an outstanding cycle life (97.5% capacitance retention after 1000 galvanostatic charge–discharge cycles), but also displays good self-healing properties (capacitance retention of about 95% after 10 healing cycles). This study can significantly contribute to the development and manufacture of conductive composites and self-healing flexible energy storage devices. [ABSTRACT FROM AUTHOR]

Bioinspired design has been central in the development of hierarchical nanocomposites. Particularly, the nacre-mimetic brick-and-mortar structure has shown excellent mechanical properties, as well as gas-barrier properties and optical transparency. Along with these intrinsic properties, the layered structure has also been utilized in sensing devices. Here we extend the multifunctionality of nacre-mimetics by designing an optically transparent and electron conductive coating based on PEDOT:PSS and nanoclays Laponite RD and Cloisite Na+. We carry out extensive characterization of the nanocomposite using transmittance spectra (transparency), conductive atomic force microscopy (conductivity), contact-resonance force microscopy (mechanical properties), and SEM combined with a variety of stress-strain AFM experiments and AFM numerical simulations (internal structure). We further study the nanoclay’s response to the application of pressure with multifrequency AFM and conductive AFM, whereby increases and decreases in conductivity can occur for the Laponite RD composites. We offer a possible mechanism to explain the changes in conductivity by modeling the coating as a 1-dimensional multibarrier potential for electron transport, and show that conductivity can change when the separation between the barriers changes under the application of pressure, and that the direction of the change depends on the energy of the electrons. We did not observe changes in conductivity under the application of pressure with AFM for the Cloisite Na+ nanocomposite, which has a large platelet size compared with the AFM probe diameter. No pressure-induced changes in conductivity were observed in the clay-free polymer either.

In this work, non-woven mats of poly(vinylidene fluoride; PVDF) containing different weight fractions (2.5, 5, 10, and 12.5 wt%) of a nanostructured conductive additive based on montmorillonite—dodecylbenzenesulfonic acid—doped polypyrrole (Mt-PPy.DBSA) have been prepared by electrospinning. The effect of Mt-PPy.DBSA content on the properties of PVDF solution, mats morphology, thermo-mechanical, and electrical properties was investigated. Polymorphism of PVDF/Mt-PPy.DBSA mats was investigated by Fourier Transform Infrared (FTIR) spectroscopy. Moreover, the electromagnetic interference shielding effectiveness (EMI SE) and EMI attenuation mechanism was investigated. In order to perform a comparative study, nanocomposites with the same weight fraction of Mt-PPy.DBSA was also prepared by solution casting. The PVDF/Mt-PPy.DBSA mats display fibers with smaller diameters than neat PVDF, due to the increment in the ionic conductivity of the solution. The incorporation of the Mt-PPy.DBSA additive slightly improved electrical conductivity of the mats and they behave like as an electrically insulating material (10−14 S cm−1), due to their porosity, that prevents the formation of a conducting network. Furthermore, the EMI SE of electrospun mats is practically null, indicating that they are almost transparent to magnetic waves. On the other hand, nanocomposites fabricated by solution casting display superior electrical conductivity (10−2 S cm−1) and EMI SE reached values of −5 dB.

This paper presents highly flexible strain sensors fabricated by extrusion-based 3D printing of electrically conductive nanocomposites consisting of multi-walled carbon nanotube (MWNT)/polydimethylsiloxane (PDMS). The effects of printing parameters and nanocomposite formulation on the piezoresistive behavior of the 3D-printed sensors are investigated. Experimental results demonstrate that the 3D printing-induced alignment of MWNTs results in the enhancement of piezoresistive sensing function of the nanocomposites. Detailed analyses are performed using the optimized sensors to characterize their sensing performance, including load rate dependency, repeatability under long-term cyclic loads, and relaxation behavior. The 3D-printed strain sensors demonstrate high flexibility, stretching to 146% strain before fracture, and exhibit a linear piezoresistive response up to 70% strain with a gauge factor of 12.15. The distribution of nanotubes in the polymer and the piezoresistive mechanism of the material are explored by in situ micro-mechanical testing under a scanning electron microscope (SEM). The developed sensors are attached on gloves to monitor the motion of a human hand, demonstrating their application wearable electronics. [ABSTRACT FROM AUTHOR]

Harmful disruptions are a result of the miniaturization and enhancement of contemporary electronics and communication. Self-healable, flexible, and lightweight elastomeric electromagnetic (EM) wave absorbers have replaced metal-based EM wave reflectors as state-of-the-art. Intending to boost the elastomeric nanocomposites' several functions, Herein, we prepared self-healable, flexible, and lightweight ZnO-XNBR/RGO nanocomposites with excellent thermal management and EMI shielding performance. A 1 mm thick nanocomposites film with DC electrical conductivity of 0.02 S/cm, thermal conductivity of 0.75 W/mK, a self-healing capability of 54.7%, 100% recyclability, excellent flexibility, and mechanical performance has been recorded with an EMI SE of − 34.2 dB in the X-band (8.2–12.4 GHz). Additionally, the uninterrupted conductive network remains unharmed by recycling, expanding, flexing, prolonged exposure to natural light, as well as chemical treatment, justifying its overall mechanical and chemical performance. These extended distortions exhibit greater than 90% retention of their shielding effectiveness (SE). In combination, the properties of our diversified elastomeric nanocomposites, including their superior shielding capability, self-healing capability, thermal management, recycling ability, and outstanding mechanical performance, provide an important guideline for developing robust elastomeric nanocomposites. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: This work presents the fabrication of high‐loading carbon nanotube (CNT)/polymer nanocomposite coatings via capillarity‐assisted assembly on fabrics for electromagnetic interference (EMI) shielding. The nanocomposite coatings formed by step‐by‐step assembly on fabrics possess a CNT loading as high as 70.9 wt%. The assistance of the capillary force in the textile increases the mass of CNTs deposited on the fabric by two orders of magnitude compared to that deposited through common electrostatic assembly. The coated fabrics thus exhibit a good EMI shielding effectiveness of 11.9 dB, indicating their capability to resist 92.7% of electromagnetic irradiation. Moreover, the nanocomposite coatings are only micrometers thick, so the coated fabrics are soft, flexible, and air permeable. In this work, a simple, scalable, and versatile method is developed to fabricate effective EMI shielding coatings on fabrics. Capillarity‐assisted assembly, which is highly controllable, represents an attractive strategy to construct high‐efficiency EMI shielding coatings through composition optimization of coatings. [ABSTRACT FROM AUTHOR]

Nowadays, light weight heating materials are attractive and conductive polymer nanocomposites (CPC) were potential applications in being used as Joule heating materials. To prepare CPCs with high efficiency and stable heating, nanocomposites of high density polyethylene (HDPE) and carbon nanotubes (CNTs) were treated by electron beam (EB) irradiation. The influence of EB irradiation on the composites was characterized by DSC, TGA, TMA, SEM, and DMA. The results showed that gel content and thermal decomposition temperature increased and the thermal expansion coefficient decreased with increasing the irradiation dose. Meanwhile, electrical and thermal conductivity of irradiated samples also increased. These were attributed to crosslinking of HDPE by EB irradiation. As a result, surface temperature (Ts) of samples after irradiation was heightened and the correspondence heat efficiency was improved. Mechanical properties of the composites were significantly improved after irradiation, especially at the temperatures which were higher than melting point of HDPE, indicating the improvement of thermal stability by irradiation crosslinking. It made the irradiated HDPE/CNTs composites good candidates for application in the electrical heating. [ABSTRACT FROM AUTHOR]

3D-printable, flexible, and conductive thermoplastic-based material was successfully developed for strain sensing applications. Thermoplastic polyurethane/multiwalled carbon nanotube (TPU/MWCNT) were compounded, their filaments were extruded, and the sensors 3D printed using fused deposition modeling. Mechanical, electrical, and piezoresistivity behaviors were investigated under monotonous and cyclic loadings. MWNCTs enhanced the printing capability of TPU by increasing its stiffness. Very modest decreases were observed in the elasticity modulus of printed nanocomposites (~ 14%, compared to that of bulk counterparts), indicating excellent interlayer adhesion and superior performance to those reported in literature. Consequently, the conductivity was largely preserved after printing, in both through-layer and cross-layer directions. The piezoresistivity gauge factors of as high as 176 were achieved under applied strains as large as 100%. A highly repeatable resistance-strain response was also obtained under cyclic loadings. The results demonstrate TPU/MWCNT as an excellent piezoresistive feedstock for 3D printing with potential applications in wearable electronics, soft robotics, and prosthetics, where complex design, multi-directionality, and customizability are demanded. [ABSTRACT FROM AUTHOR]

Flexible conductive polymer nanocomposites based on silver nanowires (AgNWs) have been extensively studied to develop the next generation of flexible electronic devices. Fiber materials with high strength and large stretching are an important part of high-performance wearable electronics. However, manufacturing conductive composites with both high mechanical strength and good stability remains challenging. In addition, the process of effectively dispersing conductive fillers into substrates is relatively complex, which greatly hampers its widespread application. Here, a simple green self-assembly preparation method in water is reported. The AgNW is evenly dispersed in aqueous, i.e., water-borne polyurethane (WPU) with water as the solvent, and a AgNW/WPU conductive nanocomposite film with an asymmetric structure is formed by self-assembly in one step. The film has high strength (≈49.2 MPa) and high strain (≈910%), low initial resistance (99.9 mΩ/sq), high conductivity (9968.1 S/cm), and excellent self-healing (93%) and adhesion. With good self-healing performance, fibers with a conductive filler spiral structure are formed. At the same time, the application of the conductive composite material with an asymmetric structure in intelligent wearability is demonstrated.

To address the shortcomings of traditional filler-based wearable hydrogels, a new type of nanochannel hydrogel sensor is fabricated in this work through a combination of the unique structure of electrospun fiber textile and the properties of a double network hydrogel. Unlike the traditional Ti 3 C 2 T x MXene-based hydrogels, the continuously distributed Ti 3 C 2 T x MXene in the nanochannels of the hydrogel forms a tightly interconnected structure similar to the neuron network. As a result, they have more free space to flip and perform micromovements, which allows one to significantly increase the electrical conductivity and sensitivity of the hydrogel. According to the findings, the Ti 3 C 2 T x MXene nanochannel hydrogel has excellent mechanical properties as well as self-adhesion and antifreezing characteristics. The hydrogel sensor successfully detects different human motions and physiological signals (e.g., low pulse signals) with high stability and sensitivity. Therefore, the proposed Ti 3 C 2 T x MXene-based hydrogel with a unique structure and properties is very promising in the field of flexible wearable devices.

Electrically conductive polymer composites have been elaborated by dispersing silver microplates into a polyvinylidene fluoride (PVDF) matrix. Silver microplates have been successfully synthesized. Their mean lateral length is about 1.15 μm, presenting a moderate aspect ratio (12–25). Synthesis is easily controlled and can produce 1–500 mg depending on the volume and the concentration of the solutions used. Electrical bulk and surface conductivity of the composites containing different filler fractions (4–20 vol.%) have been determined for each sample. Electrical percolation has been observed for each situation and was determined at 5.9 vol.% for bulk conductivity (through the thickness), while the value is shifted to 6.9 vol.% when surface conductivity is considered. The gap between the two values of percolation threshold is attributed to the orientation of fillers. Bulk conductivity and surface resistivity reaches 12.9 S m −1 and 0.123 Ω/☐ respectively at filler fraction of 15 vol.%. [ABSTRACT FROM AUTHOR]

The fascinating roles of two-dimensional (2D) nanomaterials in natural super-strong bio-composites (i.e. aragonite platelets in nacre and apatite platelets in bone) have aroused great interest in scientific communities to synthesize their artificial counterparts with controllable geometric and physical properties. The quantum 2D confinement of electrons recently revealed in graphene nanosheets further inspires to explore 2D metal nanocrystals with intrinsic anisotropic properties and quantum size effect. Among them, 2D Au nanocrystals stand out not only due to their unique structure- and environmental-dependent properties, but also due to their rapid development in synthesis approaches and emerging applications in electronics, optics, sensing and biomedicines. In this Review the aim is to rationalize numerous newly published studies on 2D Au nanocrystals and to gain insight into their shape/size controlling synthesis, diverse morphologies, properties, and applications, potentially serving a handy guide to achieve on-demand 2D Au nanocrystals. [ABSTRACT FROM AUTHOR]

Carbon-based materials are commonly used as fillers in polymer matrices for the fabrication of flexible physical and chemical sensors. Among the carbon materials, graphene has emerged as a promising next generation material replacing the traditionally used carbon black. In this work, we present the fabrication process of flexible graphene nanoplatelets/polydimethlylsiloxane (GNP/PDMS) capacitive strain sensor. In order to optimize the GNP/PDMS suspension, the dispersion of GNP in different solvents for the formation of a homogeneous suspension is examined by FT-IR spectroscopy. The sensor is fabricated by a low cost, easy to implement and rapid method using layer by layer spin-coating. The sensor exhibits linear capacitance change to small strains (≤ 0.2%). [ABSTRACT FROM AUTHOR]

This paper reports the preparation and characterization of newly developed conductive nanocomposites consisting of epoxy (EP) and polyaniline-coated halloysite nanotubes (HNT-PANI). The nanocomposites achieved its electrically conductive state (10-5 S·cm-1) and improved impact strength (76 % increase compared to neat EP) with the addition of 12 wt% HNT-PANI. Such mechanically stable conductive nanocomposite could be useful in many applications such as electromagnetic interference shielding and charge dissipating material for secondary load bearing components plus the advantage of being cost effective. [ABSTRACT FROM AUTHOR]

In this research, the thermal diffusivity of composites based on ethylene- vinyl acetate (EVA) copolymer filled with two kinds of reinforcement graphite materials was investigated. The reinforcement graphite fillers were untreated natural graphite (UG) and expanded graphite (EG). Composite samples up to 29.3 % graphite particle volumetric concentrations (50 % mass concentration) were prepared by the melt- mixing process in a Brabender Plasticorder. Upon mixing, the EG exfoliates in these films having nanosized thicknesses as evidenced by TEM micrographs. Thus, the thermal diffusivity and electrical conductivity of composites based on the ethylene-vinyl acetate matrix filled with nanostructuralized expanded graphite and standard, micro-sized graphite were investigated. From the experimental results it was deduced that the electrical conductivity was not only a function of filler concentration, but also strongly dependent on the graphite structure. The percolation concentration of the filler was found to be (15 to 17) vol% for micro-sized natural graphite, whereas the percolation concentration of the filler in nanocomposites filled with expanded graphite was much lower, about (5 to 6) vol%. The electrical conductivity of nanocomposites was also much higher than the electrical conductivity of composites filled with micro-sized filler at similar concentrations. Similarly, the values of the thermal diffusivity for the nanocomposites, EG-filled EVA, were significantly higher than the thermal diffusivity of the composites filled with micro-sized filler, UG-filled EVA, at similar concentrations. For 29.3 % graphite particle volumetric concentrations, the thermal diffusivity was 8.23 × 10 −7 m 2 · s −1 for EG-filled EVA and 6.14 × 10 −7 m 2 · s −1 for UG-filled EVA. The thermal diffusivity was measured by the flash method. [ABSTRACT FROM AUTHOR]

Abstract: Nickel nanowires with high aspect ratio (250) were elaborated and incorporated into poly(vinylidene difluoride-trifluoroethylene) up to 30vol% via solvent mixing way. These nanocomposites are characterized by a conductive behavior with a high electrical conductivity value (102 S m−1) above a very low percolation threshold (0.75vol% of metallic nanowires). The introduction of nanowires strongly depressed the matrix crystallinity. Static and dynamic mechanical analysis have been realized at low nanowire volume fraction (<10vol%). Below 5vol% of nanowires, nanocomposites remain ductile. The dynamic mechanical properties are related to the volume fraction of nanowires. A strong increase of the viscoelastic contribution related to the increase of the percentage of amorphous phase is observed. The major effect is the increase of the rubbery modulus. The highest increase of 300% is obtained for only 5vol% of nanowires; it represents an original mechanical result for low filled composites. The dependence versus nanowire content has been described by adapting the Halpin–Tsai model to high aspect ratio filler. Metallic nanowires create additional entanglements that are randomly distributed in the rubbery polymeric matrix. With their low percolation threshold, metallic nanowires based nanocomposites constitute a new class of multifunctional materials with a high conductivity associated with a ductile polymer matrix characterized by a high rubbery modulus. [Copyright &y& Elsevier]

Abstract: Single-walled and multi-walled carbon nanotubes (SWNTs and MWNTs) were characterised as-produced, after exfoliation and purification, and imbedded in the polymer matrix of nanocomposites by using various microscopic techniques. Transmission electron microscopy (TEM) shows thickness distribution as well as catalyst presence of as-produced carbon nanotubes (CNTs); scanning electron microscopy (SEM) and atomic force microscopy (AFM) are helpful tools to better understand the influence of post-treatment during exfoliation and purification, e.g. on the length distribution of CNTs; and finally SEM operated in charge contrast mode offers the potential to monitor the organisation of CNT networks in the polymer matrix of conductive nanocomposites. [Copyright &y& Elsevier]

Abstract: The morphology of conductive nanocomposites consisting of low concentration of single-wall carbon nanotubes (SWNT) and polystyrene (PS) has been studied using atomic force microscopy (AFM), transmission electron microscopy (TEM) and, in particular, scanning electron microscopy (SEM). Application of charge contrast imaging in SEM allows visualization of the overall SWNT dispersion within the polymer matrix as well as the identification of individual or bundled SWNTs at high resolution. The contrast mechanism involved will be discussed. In conductive nanocomposites the SWNTs are homogeneously dispersed within the polymer matrix and form a network. Beside fairly straight SWNTs, strongly bended SWNTs have been observed. However, for samples with SWNT concentrations below the percolation threshold, the common overall charging behavior of an insulating material is observed preventing the detailed morphological investigation of the sample. [Copyright &y& Elsevier]

Alternative energy sources such as Al-air batteries appear to be promising. However, the formation of a passive layer and the evolution of hydrogen gas during battery operation reduce capacity retention and cyclability. To address these issues, we used conductive nanocomposites (PANI@CNF) based on polyaniline (PANI) and carbon nanofibers to coat the Al electrode. The findings show that the PANI@CNF nanocomposites are able to reduce corrosion in Al electrode and prevent 92% hydrogen gas evolution. A battery with Al/PANI@0.8CNF electrode produces a high capacity density (2730 mAh g−1) and a high energy density (4067 Wh kg−1) at a current density of 10 mA cm−2. This study proposes a new strategy for improving the performance of Al-air batteries based on conductive nanocomposites. • PANI@CNF is able to suppress the corrosion of Al electrode in Al-air batteries. • PANI@CNF is able to prevent H 2 evolution in Al-air batteries with efficiency of ~92%. • A battery with Al/ PANI@0.8CNF yields high capacity density 2730 mAh g−1 • A battery with Al/ PANI@0.8CNF yields high energy density 4067 Wh kg−1 [ABSTRACT FROM AUTHOR]

This work describes the development of novel dual-stimuli-responsive nanocomposites based on silica-coated iron oxide/polyaniline (Si-MNPs/PANI) for biomedical applications. Si-MNPs/PANI nanocomposites were developed via chemical oxidative polymerization of aniline in the presence of Si-MNPs (25 and 50 wt%). Si-MNPs/PANI were obtained both in nanotubular (SPNTs) and granular (SGTs) forms by altering the synthesis parameters such as acid concentration and mixing process. The effects of nanocomposite morphology were evaluated by investigating their chemical, physical and biological properties. Material characterization was comparatively carried out via SEM, TEM, FTIR, XRD, TGA, room temperature VSM, and electrical resistivity measurements. Biological properties were evaluated by indirect in vitro cytotoxicity and in vitro hemocompatibility analyses according to ISO standards. Results indicated that Si-MNPs/PANI nanocomposites exhibited both magnetically and electrically-responsive properties. Magnetization values of Si-MNPs/PANI nanocomposites increased with increasing Si-MNPs content. However, electrical conductivity was inversely proportional to Si-MNPs content. In addition, SGTs represented remarkably higher electrical conductivity (1.1 S/cm) than SPNTs (4.8 × 10−2 S/cm), but lower saturation magnetization (21 emu/g) compared to SPNTs (27 emu/g). Furthermore, in vitro cytocompatibility and hemocompatibility of the SGTs and SPNTs varied in a dose-dependent manner, suggesting their use in certain doses for biomedical applications. In conclusion, the developed Si-MNPs/PANI, with magnetic sensitivity and electrical conductivity have potential as nanocomposites for utilization in biomedical applications, e. g. biosensing, controlled-drug delivery, bioelectronic systems, tissue engineering and regenerative medicine as active compound. Besides, the selection of the appropriate synthesis protocol allows Si-MNPs/PANI nanocomposites to exhibit superior properties according to the targeted application area. Unlabelled Image • Dual-stimuli responsive Si-MNPs/PANI nanocomposites have been successfully developed in different morphologies. • Chemical, physical and biological properties of Si-MNPs/PANI nanocomposites were evaluated by altering synthesis parameters. • Indirect in vitro cytotoxicity and in vitro hemocompatibility studies were carried out. • Si-MNPs/PANI nanocomposites hold promise for use in biomedical applications. [ABSTRACT FROM AUTHOR]

Stretchable electronics that can elongate elastically as well as flex are crucial to a wide range of emerging technologies, such as wearable medical devices, electronic skin, and soft robotics. Critical to stretchable electronics is their ability to withstand large mechanical strain without failure while retaining their electrical conduction properties, a feat significantly beyond traditional metals and silicon-based semiconductors. Herein, we present a review of the recent advances in stretchable conductive polymer nanocomposites with exceptional stretchability and electrical properties, which have the potential to transform a wide range of applications, including wearable sensors for biophysical signals, stretchable conductors and electrodes, and deformable energy-harvesting and -storage devices. Critical to achieving these stretching properties are the judicious selection and hybridization of nanomaterials, novel microstructure designs, and facile fabrication processes, which are the focus of this Review. To highlight the potentials of conductive nanocomposites, a summary of some recent important applications is presented, including COVID-19 remote monitoring, connected health, electronic skin for augmented intelligence, and soft robotics. Finally, perspectives on future challenges and new research opportunities are also presented and discussed.

• Fabrication of nanosize CuO through the plant and fruits extracts. • Preparation of antibacterial fabrics and hydrogels by CuO for biomedical area. • Application of CuO/polymer NCs in remediation industry. • Preparation of several bio-sensors and electrodes with polymer/CuO NCs. • Enhancement in the conductivity behavior of several polymers by CuO. Cupric oxide (CuO) is an affordable and valuable semiconductor material with brilliant physiochemical features such as antibacterial, antioxidant, low-cost, as well as non-toxicity. Also, this metal oxide has promising usages in water remediation, biomedical, bio-sensors, electrodes, photocatalysts, and so on. On the other side, polymers play a notable role in social life. By insertion of CuO into polymers, new materials with developed features for diverse applications can be achieved. So, there is a requirement to attain current data and collected information about them. Thus, this comprehensive review focuses on the design, properties, and applications of polymer/CuO nanocomposites (NCs). CuO NCs are introduced in three parts, bio-NCs, conductive NCs, and other NCs with different polymers, and significant usages of the manufactured materials are presented in remediation, sensing materials, drug delivery, catalysis, biomedical, nanofluids, textile, lithium-ion batteries, and solar cells. At first, this review presents a narrative summary of the eco-friendly approaches and utilization of nano-sized CuO. Then, surface treatment methods of this metal oxide by various modifiers for good dispersion in the matrixes are described. After that, various polymeric hybrids of CuO are introduced, and the influence of nano-CuO on the polymer characteristics is examined. [ABSTRACT FROM AUTHOR]

Multifunctional electronic skins (e-skins), which mimic the somatosensory system of human skin, have been widely employed in wearable devices for intelligent robotics, prosthetics, and human health monitoring. Relatively low sensitivity and severe mutual interferences of multiple stimuli detection have limited the applications of the existing e-skins. To address these challenges, inspired by the physical texture of the natural fingerprint, a novel fully elastomeric e-skin is developed herein for highly sensitive pressure and temperature sensing. A region-partition strategy is utilized to construct the multifunctional fingerprint-shaped sensing elements, where strain isolation structure of indurated film patterns are further embedded to enhance the sensitivity and effectively reduce mutual interferences between the differentiated units. The fully elastomeric graphene/silver/silicone rubber nanocomposites are synthesized with tunable properties including conductivity and sensitivity to satisfy the requirements of highly sensitive pressure and temperature sensing as well as stretchable electrodes. Remarkable progress in sensitivities for both pressure and temperature, up to 5.53 kPa -1 in a wide range of 0.5-120 kPa and 0.42% °C -1 in 25-60 °C, respectively, are achieved with the inappreciable mutual interferences. Further studies demonstrate the great potential of the proposed e-skin in the next-generation of wearable electronics for human-machine interfaces.

Polymeric composite materials are now very well established in all areas of engineering and are still increasingly being used to replace metallic counterparts. As an important advantage, composite materials hold the promise of multifunctionality, that is, fine tuning the material composition to synthetically achieve specific requirements. Among these requirements, the electrical conductivity is still limited to values orders of magnitude below those of typical metals. An approach to conductive fillers, which involves taking advantage of the favorable properties of both carbonaceous and metallic fillers to provide near metallic conductivity to the surface of carbon fiber reinforced polymer composites is herein presented by the authors. The synthesis of hybrid core‐shell high aspect ratio carbon–silver nanoparticles with a continuous silver coating, which allows both a low contact resistance between individual fillers and a greater connectivity owing to the wire‐like morphology of the particles is achieved by the authors. Incorporating the nanoparticles in an epoxy matrix yields a conductivity of 2.5 × 105 S m−1 at a loading of 6.3 vol% for a corresponding material density is of 1.9 g cm−3. The conductivity reached is high enough even to divert emulated lightning strike energy. Near‐metallic electrical conductivity at low filler loading is achieved through the made‐to measure synthesis of nanofillers. Hybrid high aspect ratio carbon–silver nanoparticles are prepared through electroless deposition on the template carbon particles and a coating is applied to a carbon‐fiber‐epoxy panel by vacuum‐assisted resin infusion. The coating demonstrates protection from emulated lightning strikes. [ABSTRACT FROM AUTHOR]