Stable Electrical Conductivity Research Articles

Two birds with one stone: A “needle-like” structure constructed on multifunctional PET fabric surface for flame retardancy and electromagnetic interference shielding

Here, a facile method is reported to prepare multifunctional PET fabrics with high flame retardancy, hydrophobicity and ideal electromagnetic shielding. PET fabric was firstly modified via polydopamine with mussel-like structure, and then DOPO@ZnO was constructed. A new type of composite PET fabric was prepared by simple, low-cost electroless Ni process and surface PDMS treatment (PpDPNP). The resulting composite fabric was extensively investigated for its stability and applicability in a complicated environment. The conductive interconnection network of modified fabric made it have excellent electrical conductivity and mechanical properties. Even after solution corrosion and washing, the prepared composite fabric could maintain a relatively stable electrical conductivity. The conductivity, tensile and elongation at break of composite fabric were 144.62 S/cm, 78.48 MPa and 167.49 %, respectively. The average electromagnetic interference shielding effectiveness (EMI SE) of PpDPNP reached 58.83 dB with 0.18 mm thickness and electroless Ni only 20 min at X-band, which was mainly due to large dielectric loss and multiple reflections. The modified PET fabric had self-extinguishing performance, and peak heat release rate (PHRR) and total heat release rate (THR) were 60.7 % and 59.8 % lower than pure PET fabric, respectively, indicating that the composite fabric had excellent flame retardancy.

Enhanced electrical performance of LiMnPO4 by carbon coating for solid-state battery applications

High-energy ball milling was employed to fabricate LiMnPO4 coated with varying carbon ratios (3%wt, 7%wt, and 10%wt), using glucose as a carbon source. The process involved pre-milling of LiMnPO4 precursors, followed by granulation through high-energy ball milling at 270 rpm for 2 h, and subsequent calcination at 700 °C without an inert gas flow. XRD analysis discerned the phases and structure of LiMnPO4, confirming the successful attainment of a single-phase LiMnPO4 without impurities. Rietveld refinement of the XRD data elucidated the crystallographic details, affirming the material's orthorhombic olivine structure with precise lattice parameters, thereby underpinning the structural integrity essential for electrochemical applications. FE-SEM analysis revealed uniformly distributed semi-sphere particles, with sizes ranging from 130 nm for LM to 183 nm for LM-10%C. FTIR analysis delineated the internal modes of vibration in the olivine structure and verified the presence of carbon on the powder surface. Electrical measurements conducted within the frequency range of 20 Hz–100 kHz demonstrated an increase in electrical conductivity with an escalation in carbon concentration, ranging from 31 μΩ−1m−1 to 75 μΩ−1m−1 for 0%C and 10%C, respectively. A temperature-dependent study spanning 30–160 °C revealed stable electrical conductivity behavior for the samples, with a marginal increase observed at elevated temperatures.

Fabrication of Porous Non‐Enzymatic Glucose Sensing Electrodes Through Nanosecond‐Laser Patterning of Metal–Organic Frameworks

AbstractNanosecond laser patterning of Copper Metal–Organic Framework (Cu‐MOF) coated substrates is performed to fabricate non‐enzymatic glucose sensing electrodes. The Cu‐MOF coated glass substrate with a cover glass is subjected to a laser patterning process; the amount of MOF, laser fluence, and scan speeds mainly influenced the patterning process. The electrodes are fabricated on coated and covered glass with varying electrical conductivity due to the high laser energy absorptivity. The patterned electrodes consist of graphitic carbon incorporated with nano‐Cu and show a stable electrical conductivity on the coated substrates. The electrodes are chemically active in the Fe2+/Fe3+ redox system; however, their activity varies with patterning conditions. The electrochemical studies in alkaline electrolytes reveal that the as‐fabricated electrodes can sense the glucose molecule in the linear concentration range of 0.025–1.0 and 1.0–10.0 mm, with a maximum sensitivity of 3260.3 µA mM−1 cm−2 and a response time of no more than 5 s, and a limit of detection (LOD) of 0.25 µm. The current recovery rate is higher (> 80%) when adding glucose molecules than when adding other interference molecules, confirming that the electrode is selective toward glucose sensing. The results reveal that the fabricated electrodes act as stable, reusable, non‐enzymatic glucose‐sensing electrodes.

A dynamically stable self-healable wire based on mechanical-electrical coupling.

The rise in wearable electronics has witnessed the advancement of self-healable wires, which are capable of recovering mechanical and electrical properties upon structural damage. However, their highly fluctuating electrical resistances in the range of hundreds to thousands of ohms under dynamic conditions such as bending, pressing, stretching and tremoring may seriously degrade the precision and continuity of the resulting electronic devices, thus severely hindering their wearable applications. Here, we report a new family of self-healable wires with high strengths and stable electrical conductivities under dynamic conditions, inspired by mechanical-electrical coupling of the myelinated axon in nature. Our self-healable wire based on mechanical-electrical coupling between the structural and conductive components has significantly improved the electrical stability under dynamic scenarios, enabling precise monitoring of human health status and daily activities, even in the case of limb tremors from simulated Parkinson's disease. Our mechanical-electrical coupling strategy opens a new avenue for the development of dynamically stable electrodes and devices toward real-world wearable applications.

Ultrathin Mixed Ionic-Electronic Conducting Interlayer via the Solution Shearing Technique for High-Performance Lithium-Sulfur Batteries.

The commercialization of lithium-sulfur (Li-S) batteries has been hampered by diverse challenges, including the shuttle phenomenon and low electrical/ionic conductivity of lithium sulfide and sulfur. To address these issues, extensive research has been devoted to developing multifunctional interlayers. However, interlayers capable of simultaneously suppressing the polysulfide (PS) shuttle and ensuring stable electrical and ionic conductivity are relatively uncommon. Moreover, the use of thick and heavy interlayers results in an unavoidable decline in the energy density of Li-S batteries. We developed an ultrathin (750 nm), lightweight (0.182 mg cm-2) interlayer that facilitates mixed ionic-electronic conduction using the solution shearing technique. The interlayer, composed of carbon nanotube (CNT)/Nafion/poly-3,4-ethylenedioxythiophene:tetracyanoborate (PEDOT:TCB), effectively suppresses the shuttle phenomenon through the synergistic segregation and adsorption effects on PSs by Nafion and CNT/PEDOT, respectively. Furthermore, the electrical/ionic conductivity of the interlayer can be improved via counterion exchange and homogeneous Li+ ion flux/good wettability from SO3- functional group of Nafion, respectively. Enhanced sulfur utilization and reaction kinetics through polysulfide shuttle inhibition and facilitated electron/ion transfer by interlayer enable a high discharge capacity of 1029 mA h g-1 in the Li-S pouch cell under a high sulfur loading of 5.3 mg cm-2 and low electrolyte/sulfur ratio of 5 μL mg-1.

Microstructure and electrical property of composite Co-W/CuO multilayered oxide coating for solid oxide fuel cell interconnector

To overcome the challenges related to the electrical resistance owing to the growth of the Cr-containing oxide layer in the SOFC system at high temperature, a composite coating of Co-W/CuO was fabricated on ferritic stainless steel for interconnectors by composite electroplating and pre-oxidation treatment. Compared to the Co-W alloy coating, the addition of CuO led to the formation of Cu-Co spinels and Cu-W composites, which affected the surface microstructure of the coating. Scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS) and transmission electron microscopy (TEM) investigations shows that CuWO4 nano-particles formed in the Cr-rich layer beneath the CoWO4 layer, of which the lattice deviation leads to the formation of oxygen vacancies. The CuWO4 acted as conductive pathways, reducing the electrical resistance. Long-term oxidation exposure further demonstrated that the Co-W/CuO coated SUS 430 exhibited a stable electrical conductivity of 10.23 mΩ cm2.

Optimization of a LaNiO3 Bottom Electrode for Flexible Pb(Zr,Ti)O3 Film-Based Ferroelectric Random Access Memory Applications

The direct growth of ferroelectric films onto flexible substrates has garnered significant interest in the advancement of portable and wearable electronic devices. However, the search for an optimized bottom electrode that can provide a large and stable remnant polarization is still ongoing. In this study, we report the optimization of an oxide-based LaNiO3 (LNO) electrode for high-quality Pb(Zr0.52Ti0.48)O3 (PZT) thick films. The surface morphology and electrical conductivity of sol-gel-grown LNO films on a fluorophlogopite mica (F-mica) substrate were optimized at a crystallization temperature of 800 °C and a film thickness of 120 nm. Our approach represents the promising potential pairing between PZT and LNO electrodes. While LNO-coated F-mica maintains stable electrical conductivity during 1.0%-strain and 104-bending cycles, the upper PZT films exhibit a nearly square-like polarization–electric field behavior under those stress conditions. After 104 cycles at 0.5% strain, the remnant polarization shows decreases as small as ~14%. Under flat (bent) conditions, the value decreases to just 81% (49%) after 1010 fatigue cycles and to 96% (85%) after 105 s of a retention test, respectively.

Study on Heating Performance and Flexural Strength Properties of Electrically Conductive Mortar

The use of electrically conductive mortar (ECM) is a relatively new construction material technology developed to obtain high conductivity and mechanical strength. This study presents an experimental investigation on the heating performance and flexural strength properties of ECM mixed with carbon fiber (CF) and steel fiber (SF), which are conductive fibers. Furthermore, the internal microstructure of the ECM was analyzed with a scanning electron microscope (SEM) and thermogravimetric analysis was carried out using a thermogravimetric analyzer (TGA) device. The results of the experiment showed that the incorporation of SF had little effect on heating performance. In the case of CF, however, it was found that as the fiber contents and applied voltages increased, the heating performance increased. In particular, the maximum heating temperature of the ECM-CF125 specimen was 145.1 °C at an applied voltage of 30 V and an electrode spacing of 40 mm, which was about 7.3 times higher than the initial temperature (20 °C). In addition, the flexural strength of ECM mixed with SF was higher than that of plain mortar (PM), whereas the ECM-CF125 specimen showed a greater tendency to significantly decrease. It was confirmed that the hydration products and internal microstructures of the specimens were unaffected by repetitive electrical heating, and the ECM maintained stable electrical conductivity.

A cerebral cortex-like structured metallized elastomer for high-performance triboelectric nanogenerator

The advancement of wearable electronics, particularly triboelectric nanogenerators (TENGs), relies on the development of flexible, stretchable, and compressible electrodes that possess a large active surface area, high electrical conductivity, and excellent mechanical stability and deformability. However, existing elastomeric electrodes face challenges in meeting all of these requirements. Herein, we present a novel approach to address these limitations and create electrodes with elastomeric properties, stable metal-like electrical conductivity, and an expanded active surface area. For this goal, we perform an assembly of metal nanoparticles (NPs) in toluene and amine-functionalized organic linkers in alcohol onto the thiol-functionalized, embossed-structured elastomer. Particularly, the assembly process involves ligand exchange reaction-mediated metal NPs and subjecting them to solvent-swelling/deswelling of the embossed PDMS. This process induces the formation of cerebral cortex-like structured elastomer electrode, which is subsequently electroplated with Ni. The resulting electrodes exhibit metal-like electrical conductivity, elastomer-like flexibility, and cerebral cortex-like structure with substantially large surface area and high stress relieving properties. When combined with an intaglio-structured dielectric PDMS electrode, the device exhibits impressive TENG performance, surpassing the performance of conventional TENGs. This approach provides a basis for developing and designing a variety of high-performance flexible electronics, including TENGs.

Seeding carbon nanotube microemulsions in elastomer films for hetero-structured porous stretchable composites

Stretchable electrodes play a crucial role in wearable electronics for high-efficiency carrier transport in the information communication, yet it is challenging to achieve high electrical conductivity at large strain for stretchable and porous conductive composites. Here, a simple yet efficient strategy is proposed to fabricate highly conductive, porous and stretchable composites via seeding hydrophilic carbon nanotube (CNT) oil-in-water microemulsions in elastomer films prior to growing silver nanoparticles (AgNPs) in situ. It aims at forming a dual heterogeneous structure of CNT microspheres in the elastomeric films containing conductive networks of AgNPs, which allow to guarantee the overall good electrical conductivity. Unlike the rapid propagation of cut-through microcracks in conventional conductive network of AgNPs under strain, the mechanical and electrical dual hetero-structured CNT microspheres in the conductive networks can sustain high electrical conductivity at large strains by blocking and cutting off microcrack propagation. Therefore, the porous composite electrodes show electrical conductivity above 103 S/cm at 200% strain thanks to the efficient dissipation of strain energy by dual hetero-structured CNT microspheres, which is controlled by CNT concentration in the oil-in-water microemulsions. Besides, the as-fabricated porous composites sustain high yet stable electrical conductivity at various kinds of mechanical deformations, such as tension, bending, twisting and a combination of them, allowing for the promising application in stretchable and wearable electrodes.

Electrical conductivity and heating performance of hybrid steel fiber-reinforced SCC: The role of high-volume fiber and micro fiber length

Recently, it has become very popular to develop electrically conductive concrete composites for active deicing and snow-melting of transportation infrastructure. These composites should have stable electrical conductivity and a uniform heating performance, as well as high mechanical and durability properties, for a sustainable solution. In this context, the main motivation of this study is to develop an electrically conductive hybrid steel fiber reinforced self-compacting concrete (HSFR-SCC) composite for ice and snow removal applications. The electrical conductivity and heating performance of self-compacting concrete (SCC) mixtures having different fiber volumes (1.00, 1.25, and 1.50%) and the combination of macro steel fiber with micro steel fibers having lengths of 13 and 6 mm as single and hybrid were experimentally investigated for the first time. For this purpose, a total of ten SCC mixtures were designed, one of which was non-fiber Control, the others had steel fiber volumes of 1.00, 1.25, and 1.50% and different fiber combinations. Workability (slump-flow, T500 and J-ring) tests on HSFR-SCC mixtures were performed with reference to EFNARC. Then, mechanical (compressive and flexural strengths), electrical resistivity, and heating performance tests of 90-day HSFR-SCC samples were carried out. Before the electrical resistivity and heating performance tests, HSFR-SCC samples were kept in an oven at 105 ± 5 °C for 24 h to measure their most critical state (dry) performance. Moreover, using multiple linear regression analysis, empirical equations and contour plots were developed to predict the electrical resistivity and temperature increase values of HSFR-SCC samples depending on fiber volumes and combinations. Considering the experimental results, electrically conductive HSFR-SCC mixtures with satisfactory workability and high strength were obtained. The addition of various volumes and combinations of steel fiber to SCC significantly improved the electrical conductivity and heating performance of the concrete, while the mixtures with hybrid fiber were the best for all fiber volumes. As for the different micro fibers added to the HSFR-SCC mixtures, the 13 mm length micro steel fiber was much more effective in improving the electrical resistivity and heating performance of the samples compared to the 6 mm length micro steel fiber. Also, it was found that the fiber-reinforced index of electrically conductive HSFR-SCC samples could be 0.87 for effective and efficient electrical conductivity.

Highly Robust and Strain-Resilient Thin Film Conductors Featuring Brittle Materials.

Stretchable conductors with stable electrical conductivity under various deformations are essential for wearable electronics, soft robots, and biointegrated devices. However, brittle film-based conductors on elastomeric substrates often suffer from unexpected electrical disconnection due to the obvious mechanical incompatibility between stiff films and soft substrates. We proposed a novel out-of-plane crack control strategy to achieve the strain-insensitive electrical performance of thin-film-based conductors, featuring conductive brittle materials, including nanocrystalline metals (Cu, Ag, Mo) and transparent oxides (ITO). Our metal film-based conductors exhibit an ultrahigh initial conductivity (1.3 × 105 S cm-1) and negligible resistance change (R/R0 = 1.5) over wide strain range from 0 to 130%, enabled by film-induced substrate cracking and liquid metal-induced electrical self-repairing. They could function well under multimodal deformations (stretching, bending, and twisting) and severe mechanical damage (cutting and puncturing). We demonstrated the strain-resilient electrical functionality of metal film-based conductors in a flexible light-emitting diode display that shows high mechanical compliance.

High-Strength Double-Network Conductive Hydrogels Based on Polyvinyl Alcohol and Polymerizable Deep Eutectic Solvent.

Conductive hydrogels feature the flexibility of soft materials plus conductive properties providing functionality for effectively sticking to the epidermis and detecting human activity signals. Their stable electrical conductivity also effectively avoids the problem of uneven distribution of solid conductive fillers inside traditional conductive hydrogels. However, the simultaneous integration of high mechanical strength, stretchability, and transparency through a simple and green fabrication method remains a great challenge. Herein, a polymerizable deep eutectic solvent (PDES) composed of choline chloride and acrylic acid was added to a biocompatible PVA matrix. The double-network hydrogels were then simply prepared by thermal polymerization and one freeze-thaw method. The introduction of the PDES significantly improved the tensile properties (1.1 MPa), ionic conductivity (2.1 S/m), and optical transparency (90%) of the PVA hydrogels. When the gel sensor was fixed to human skin, real-time monitoring of a variety of human activities could be implemented with accuracy and durability. Such a simple preparation method performed by combining a deep eutectic solvent with traditional hydrogels offers a new avenue to construct multifunctional conductive hydrogel sensors with excellent performance.

Cold spray direct writing of flexible electrodes for enhanced performance triboelectric nanogenerators

Triboelectric nanogenerator (TENG) is an emerging energy harvesting device to effectively harness various mechanical energy sources. In TENG technology, polymers are of particular interest as tribo-negative materials owing to their unique properties (e.g., charge storage capability, impact resistance, flexibility, low cost, recyclability, etc.). Despite significant advances, one major challenge for TENG is to develop high-performance back electrodes that are conformably attached to the tribo-negative polymer substrates to fully exploit the potential of TENG in energy harvesting. To this end, the present study is aimed to employing direct “cold spray” particle deposition as just one-step fabrication method for high-performance electrodes on flexible polymers. In this regard, Tin (Sn) particles are directly written on the polymer (PET) surface by cold spraying to achieve conformal electrodes with high-adhesive strength and stable electrical conductivity. The resulting electrodes are thoroughly characterized in terms of microstructure, adhesion strength, and electrical performance. Arc-shaped TENG devices with both traditional aluminum (control) and cold-sprayed Sn electrodes are fabricated, followed by evaluating the TENGs' performance. Owing to the strong adhesion and micro-roughness (i.e., Ra = 4.865 μm) of the Sn electrodes, electricity generation performance was found to be improved by ≈2.4 folds as compared to the control TENG. The TENG with Sn electrode can generate an open-circuit output voltage of up to 243 V with a maximum output power of 130 mW/m2, thereby indicating the promising potential of the cold spray technique in TENG technology.

Flexible Wearable Electronic Fabrics with Dual Functions of Efficient EMI Shielding and Electric Heating for Triboelectric Nanogenerators

Traditional conductive fabrics are prepared by the synthesis of conductive polymers and the coating modification of metals or carbon black conductive materials. However, the conductive fabrics cause a significant decline in performance after washing or mechanical wear, which limits their application. Moreover, the single function of the traditional conductive fabric is also the reason that limits its wide application. In order to prepare a wearable, stable, high-performance, washable, multifunctional conductive fabric, we have carried out related research. In this work, polydopamine was used as a bonding layer, an adsorption reduction layer, and a protective layer to improve the bonding between silver nanoparticles and carbon nanotubes (CNTs) on the polyester fabric surface so as to prepare a multifunctional conductive fabric with a high-stability "sandwich" structure, in which a Ag-NPS@CNT structure acting as an intermediate conductive layer formed on the inner layer PDA@CNT by electroless silver plating and the outermost layer PDA@CNT coated on the surface of the intermediate conductive layer by the impregnation-drying method. The sheet resistance of an E-Fabric can reach 2.11 Ω/□ due to the uniform and dense conductive path formed by the special structure Ag-NPs@CNT. At a low voltage of 1.5 V, the E-Fabric can reach 117 °C in 50 s and remain stable. The electrical conductivity and current heating properties of the E-Fabric remain good even after multiple washing or bending tests. Due to its stable and outstanding electrical conductivity, the E-Fabric has an electromagnetic shielding efficiency (SET) of 35.3 dB in the X-band (8.2-12.4 GHz). In addition, E-Fabric-based spin-coated poly(methyl methacrylate) or polydimethylsiloxane electrodes exhibit excellent performance in nanogenerators. Through the low-frequency friction of the human body, transient voltages up to 4 V can be generated from a 2 cm × 2 cm electrode sample. The output power of a single generator can reach about 12 nW/cm2. Therefore, an E-Fabric is considered to have great potential in the fields of electric heating, electromagnetic shielding, and smart wearable devices.

Hydrodynamics of a high Alpine catchment characterized by four natural tracers

Abstract. Hydrological processes in high-elevation catchments are strongly influenced by alternating snow accumulation and melt in addition to summer rainfall. Although diverse water sources and flow paths that generate streamflow in the world's water towers emerge from these two driving inputs, a detailed process understanding remains poor. We measured a combination of natural tracers of water at a high frequency, including stable isotope compositions, electrical conductivity (EC), and water and soil temperature to characterize hydrological processes in a snow-dominated Alpine catchment and to understand the diversity of streamflow sources and flow paths. Stable isotope composition of the sampled water revealed the prominence of snowmelt year-round (even during winter baseflow), and a strong flushing of the entire system with snowmelt at the start of the main melt period, sometimes referred to as the freshet, led to a reset, or return to baseline, of the isotopic values in most sampled water. Soil temperature measurements help identify snow-free periods and indicate sub-snowpack local flow, for example, in the case of rain-on-snow events. Water temperature measurements in springs can indicate flow path depth. EC measurements reflect the magnitude of subsurface exchange and allow for the separation of subsurface snowmelt contribution to streamflow from the contribution of stored groundwater. These insights into the details of streamflow generation in such a dynamic environment were only made possible due to intense, year-round water sampling. The sampled tracers are revealed to complement each other in important ways particularly because they were sampled during winter and spring, both snow-covered periods, the importance of which is a key implication of this work.

Anhydrous Thermogalvanic Gel for Simultaneous Waste Heat Recovery and Thermal Management of Electronics

Due to their distinctive characteristics of adequate flexibility, stability, and functional diversity, thermogalvanic gels have demonstrated tremendous promise in the area of renewable energy sources. However, their inability to adapt to low or high temperature environments greatly limits their practical applications. In this work, an anhydrous thermogalvanic gel prepared from dimethyl sulfoxide (DMSO)/ethylene glycol (EG) binary organic solvent is developed with Fe3+/2+ as a redox pair, which displays an exceptional temperature tolerance (−80 to 80 °C) and remarkable antidrying property (80% weight retention at 70 °C after 12 h), while maintaining stable mechanical flexibility and electrical conductivity over a wide temperature range. These merits result from the formation of numerous hydrogen bonds between DMSO and EG molecules, which prevent crystallization and hinder evaporation of the solvent simultaneously. As an applicative demonstration, by placing the thermogalvanic gel on the surface of a charging battery/charger/chip, it acts as a thermal-conductive network while performing the thermal-electric conversion, revealing a viable strategy for simultaneous waste heat recovery and thermal management. This research provides new insight into the creation of flexible thermoelectric materials for energy recovery and self-powered wearable electronics.

Highly robust and flexible micro-supercapacitors based on medium-entropy carbide nanowires toward sub-ambient temperature operation

Currently, the exploration of energy conversion/storage devices for harsh environment applications with satisfying property is still a grand challenge. In the present work, the highly robust and flexible micro-supercapacitors (MSCs) based on (Ta, Ti, Nb)C nanowires (NWs) and activated carbon hybrid structures as the electrode materials are reported. Given to the inherent advantages of (Ta, Ti, Nb)C NWs, e.g. stable electrical conductivity and mechanical flexibility, and abundant porous structure stemed from cross-linked (Ta, Ti, Nb)C NWs and bamboo-based active carbon, the as-prepared (Ta, Ti, Nb)C/C-MSCs show high electrochemical performance, mechanical stability, and temperature tolerance over a wide temperature range. Remarkably, the as-constructed (Ta, Ti, Nb)C/C-MSCs can endure the sub-ambient temperature operation down to −50 °C with a capacitance retention of 82.7% and present capacitance retention up to 97.7% over one cycle of cooling and heating between −50 and 25 °C, compared with that at room temperature. Even under progressive variation in temperatures ranged between 25 and -50 °C, the capacitance retention keeps up to 92.6% over 9000 cycles, representing their promising to be serviced as highly robust MSCs against harsh low-temperature conditions for energy storage.

Silicon carbide based nanocomposite of polythiophene with high thermally stable DC electrical conduction and ethanol sensing

Here in this work, we are reporting thermally stable DC electrical conductivity of silicon carbide nanocomposite with polythiophene and its sensing behavior towards ethanol. Polythiophene (PTh) and Polythiophene/SiC (PTh/SiC) nanocomposite were synthesized by in-situ process of polymerization via oxidation route using CTAB (cetyltrimethylammonium bromide) as a surfactant and characterized by X-rays diffraction (XRD), Fourier transforms infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM) and Transmittance electron microscopy (TEM) analysis. Stability of DC electrical conductivity of PTh and PTh/SiC nanocomposite were examined at different temperature ranges from 50 °C to 130 °C in isothermal and cyclic conditions. PTh/SiC nanocomposite showed high steadiness of DC electrical conductivity than that of PTh in different thermal ageing conditions. Sensing behavior of PTh/SiC nanocomposite towards 1 M ethanol was recognized as steady with time and reversible in cyclic process.

Self-heating ultra-high performance concrete with stainless steel wires for active deicing and snow-melting of transportation infrastructures

The development of self-heating concrete composites with stable electrical conductivity and strong heating capability as well as high mechanical properties is the key for achieving active deicing and snow-melting of transportation infrastructures. Due to their microscale diameter and high aspect ratio, stainless steel wires (SSWs) can form an extensive electrically and thermally conductive as well as reinforcing network inside concrete at a low content. Together with the stainless feature of SSWs as well as high structural compactness and durability of ultra-high performance concrete (UHPC), SSWs reinforced UHPC is expected to be developed into self-heating composites with strong and stable heating capability as well as ultra-high mechanical performance and durability. Therefore, this study evaluated the self-heating capability as well as active deicing and snow-melting performances of such composites. The developed SSWs reinforced UHPC slab demonstrates stable electrical conductivity and strong self-heating capability in cycle uses as well as efficient active deicing and snow-melting properties under different environmental conditions. The electrical resistivity of SSWs reinforced UHPC is only 2.58 Ω cm and it is hardly affected by the change in temperatures, numbers of cyclic self-heating, and numbers of deicing and snow-melting. The SSWs reinforced UHPC slab can be heated from 21.4 °C to 82.4 °C in 16.18 min under the voltages of 30 V in an indoor environment at a temperature of 21.2 °C. The slab only needs 28.98 min, 15.20 min, and 27.31 min to completely melt 9 mm of ice in a freezer at a temperature of −25.6 °C, 5 cm of naturally accumulated snow and 2 cm of artificially compacted snow in an outdoor environment at a temperature of about −5 °C with the wind speed up to 5.36 m s−1. Furthermore, thanks to their characteristics of no adverse effect on vehicle tires and excellent fatigue resistance, self-heating SSWs reinforced UHPC shows promising application prospects in active deicing and snow-melting of transportation infrastructures (e.g., airport runway, pavement and bridge deck) suffering from frigid weather.