Conductive Multi-walled Carbon Nanotubes Research Articles

Transformation from Electromagnetic Inflection to Absorption of Silicone Rubber and Accordion-Shaped Ti3C2MXene Composites by Highly Electric Conductive Multi-Walled Carbon Nanotubes.

Electromagnetic (EM) pollution becomes more penetrating in daily life and work due to more convenience provided by multi-electrical devices, as does secondary pollution caused by electromagnetic reflection. EM wave absorption material with less reflection is a good solution to absorb unavoidable EM radiation or reduce it from the source. Filled with two-dimensional Ti3SiC2MXenes, silicone rubber (SR)composite demonstrated a good electromagnetic shielding effectiveness of 20 dB in the X band by melt-mixing processes for good conductivity of more than 10-3 S/cm and displayed dielectric properties and a low magnetic permeability; however, the reflection loss was only -4 dB. By the combination of one-dimensional highly electric conductive multi-walled carbon nanotubes (HEMWCNTs) and MXenes, the composites achieved the transformation from electromagnetic inflection to an excellent absorbing performance to reach a minimum reflection loss of -30.19 dB due to electric conductivity of above 10-4 S/cm, a higher dielectric constant, and more loss in both dielectric and magnetic properties. Ni-added multi-walled carbon nanotubes were not able to achieve the transformation. The as-prepared SR/HEMWCNT/MXene composites have potential application prospects in protective layers, which can be used for electromagnetic wave absorption, electromagnetic interference suppression of devices, and stealth of the equipment.

Electrically conductive crystalline polylactide nonwovens obtained by electrospinning and modification with multiwall carbon nanotubes

Polylactide nonwovens were electrospun from solutions and then crystallized, one in α-form, and another, S-PLA, made of poly(l-lactide) and poly(d-lactide) 1:1 blend, in scPLA crystals with high melting temperature, close to 220 °C. To make the nonwovens electrically conductive, they were coated with multiwall carbon nanotubes (MWCNT) by padding and dip-coating with an aqueous dispersion of MWCNT. The electrical conductivity evidenced the formation of the electrically conductive MWCNT network on the fiber surfaces. Depending on the coating method, the surface resistivity (Rs) of S-PLA nonwoven of 1.0 kΩ/sq and 0.09 kΩ/sq was reached. To study the effect of surface roughness, before the modification the nonwovens were etched with sodium hydroxide, which additionally made them hydrophilic. The effect of etching depended on the coating method and led to an increase or decrease of Rs, in the case of padding or dip-coating, respectively. All MWCNT-modified nonwovens, unetched and etched, were hydrophobic with water contact angles of 138–144°. Scanning electron microscopy corroborated the presence of MWCNT on the fiber surfaces. Impedance spectroscopy confirmed the dominant role of the network of MWCNT direct contacts on the electrical properties of MWCNT-modified nonwovens in a broad frequency range.

Synergistic effect of Fe (III) doping and MWCNTs integration on the electrochemical performance of nickel sulfide nanoparticles for hybrid supercapacitor applications

In this report, Iron (Fe) doped nickel sulfide (NiS) nanoparticles integrated with multi-walled carbon nanotubes (MWCNTs) have been prepared by hydrothermal and ultrasonication approach. X-rays studies of synthesized samples showed the existence of single-phase hexagonal Fe–NiS along MWCNTs with crystallite size of 13.19 nm. SEM images indicated spherical Fe–NiS particles encapsulated by long and thin thread like MWCNTs. Fe–NiS@MWCNTs was drop casted on nickel foam (NF) for the supercapacitor application. Fe–NiS@MWCNTs/NF offered a specific capacity of 662C g−1 at 5 mV s−1 with excellent cyclic stability. Fe–NiS@MWCNTs/NF maintained 70.2% of initial specific capacity at a high scan rate of 100 mV s−1. For impedance studies, a small equivalent series resistance (ESR = 2.30 Ω) and charge transfer resistance (RCT = 3.12 Ω) were observed for Fe–NiS@MWCNTs/NF. The superior electrochemical performance of Fe–NiS@MWCNTs/NF can be accredited to the large surface area and intervened network of Fe–NiS@MWCNTs. Pseudocapacitive Fe–NiS and highly conductive MWCNTs generate synergistic effects that ultimately boost up the specific capacity of Fe–NiS@MWCNTs/NF electrode. The excellent electrochemical performance of proposes Fe–NiS@MWCNTs/NF as effective electroactive material for supercapacitor applications.

Electron transport engineering of carbon hybrid network towards physiological signal monitoring and efficient heat management

E-skin that can mimic the complex functions of human skin has attracted considerable interest in health monitoring and medical diagnosis. However, the accurate and reliable detection of multiple external stimuli using a sole sensing component remains challenging. Herein, we describe a flexible strain-temperature sensor fabricated by employing conductive 1D multi-walled carbon nanotubes (MWCNTs), 2D reduced graphene oxide (RGO) and a flexible polydimethylsiloxane (PDMS) substrate to construct a sandwich structure. Consequently, the flexible MWCNTs@RGO hybrid film with optimized conductivity exhibits a high gauge factor (GF = 1888) at a strain up to 40 %, prominent long-term durability (8000 cycles at 25 % strain), low strain detection (0.05 %) and rapid response (57 ms). The significantly enhanced performance is attributed to the synergy of tubular MWCNTs and layered RGO, as revealed by finite element analysis. Additionally, the hybrid film sensor exhibits temperature-sensing ability with a typical negative temperature coefficient of resistance and delivers an improved sensitivity upon thermal stimulus via prestrain-induced microcracks and a thermal expansion strategy. Owing to its excellent sensing properties, it can not only detect human motions in various situations but also be adopted as a temperature warning/cooling system, supporting its feasibility for use by patients lacking temperature perception and bringing convenience to daily life.

Stretchable self-adhesive and self-powered smart bandage for motion perception and motion intention recognition

The research on flexible and stretchable self-powered sensors perceiving human body motion and physiological signals has become a hot spot in recent years. Aided with machine learning, more features of the human motion and physiological signals can be intelligently interpreted. Here, we first propose a triboelectric nanogenerator (BMS-TENG) based on highly conductive multi-walled carbon nanotubes, flexible and stretchable silica gel, and a self-adhesive elastic bandage, which is highly stretchable and self-adhesive for easy fixation on the skin. The maximum stretchability of the sensor is 502%. BMS-TENG sensor can collect a variety of human motion and physiological signals, such as bending fingers and elbows, lifting legs, breathing, and swallowing. With the support of machine learning, we propose a smart bandage system capable of acquiring motion signals and recognizing intentions. By collecting signals from the forearm near the elbow instead of the fingers, the smart bandage can recognize various gestures and muscle action features. Applications of intention-manipulating diverse gestures from the robotic hand and individual identification work well. The system has great potential in human motion monitoring, electronic skin, human-computer interaction, gesture recognition, biomedicine, and other fields.

Ni-foam based heterogenous Bi2S3 polyhedrons/multi walled carbon nanotubes (Bi2S3@MWCNTs/NF) as an advanced battery type electrode for enhanced supercapacitor performance

In current study, we report the hydrothermal synthesis of highly electroactive bismuth trichloride (Bi2S3) polyhedrons, modified with multi walled carbon nanotubes (MWCNTs). The physiochemical characterizations of pure Bi2S3 and Bi2S3@MWCNTs composite were carried out through X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). XRD data revealed orthorhombic crystal structure of Bi2S3 having crystallite size of ∼13.23 nm, that got reduced to ∼10.81 for Bi2S3@MWCNTs composite. Polyhedral Bi2S3 showed some tendency to aggregate after fabricating with MWCNTs. Functional group analysis confirmed the formation of Bi–S bonds through multiple metal-sulfide bonding vibrations in the finger print region (880–550 cm−1). For electrochemical tests, Bi2S3/NF and Bi2S3@MWCNTs/NF were applied as electrodes. Due to the synergistic effects from highly conductive MWCNTs and pseudo-active Bi2S3, as prepared Bi2S3@MWCNTs/NF exhibited a significant enhancement in electrochemical response. The specific capacity of Bi2S3@MWCNTs/NF was measured as 625.1 C g−1, that was ∼1.45 times greater than that of non-fabricated Bi2S3 polyhedrons. Additionally, Bi2S3@MWCNTs/NF delivered a better charge/discharge efficiency. The values of RES (2.25 Ω) and RCT (3.54 Ω) prominently decreased for Bi2S3@MWCNTs/NF due to low internal and diffusional resistance.

Flexible high-capacity and long-cyclability hydrogel batteries enabled by polyvalent vanadium ion redox chemistry

Aqueous secondary batteries based on nonflammable electrolytes are attracting extensive attention due to high safety, fast reaction kinetics, and low cost. Herein, we report the development of flexible hydrogel batteries based on polyvalent vanadium ion redox chemistry. In this battery, symmetrical composite hydrogel electrodes used as both cathode and anode are prepared by in-situ fabrication of highly porous 3D poly(N-isopropylacrylamide) scaffold alongside conductive multi-walled carbon nanotube networks and swollen with redox-active vanadium ion electrolyte. The abundant nanoscale porosity and channels in the hydrogel matrix are conducive to the infiltration/diffusion of vanadium ions and H+ ions, thus enabling high areal loading mass (13 mgv cm−2) and large areal capacity (0.99 mAh cm−2). The active materials in the flexible electrodes exist in the form of composite hydrogel state, which is beneficial to facilitate ion transport and electrochemical kinetics, delivering an impressive power density of 11 mW cm−2 at 10 mA cm−2. Moreover, the flexible vanadium ion hydrogel batteries also exhibit excellent mechanical properties and long-term durability of 1000 cycles. These merits make them promising for the applications in wearable and smart electronics.

A study on development of silicone rubber with conductive carbon, polyaniline, MWCNT composite for EMI shielding

The multiwall carbon nanotubes (MWCNTs) were grown by CVD method and using Ni impregnated zeolite as a substrate. The prepared MWCNT diameter varied from 10 to 60 nm and length in few microns. The silicone rubber (SR) was mixed well with conductive carbon, Polyaniline (PANI) and MWCNTs in two roll mill. The prepared silicone rubber materials were fabricated in the form of sheets with dimensions of 200 mm × 200 mm × 2 mm by using compression molding technique. The prepared sheets were subjected for EMI shielding efficiency measurements at low frequency (< 1.5 GHz) and high frequency range from 1 GHz to 18 GHz. At high frequency the shielding effectiveness of the Conducting Silicone Rubber and Conductive silicone rubber with MWCNT was found to be 24 dB and 48 dB. The volume resistivity measurements were also carried for all the prepared silicone rubber sheets, the results reveals that SR + MWCNT, CSR + MWCNT composites shows volume resistivity 4032 and 20.7 Ω.cm respectively. This confirms the conductivity of CSR + MWCNT is enough to exhibit good Shielding Effectiveness.

Nickel Hydroxide Nanoflake/Carbon Nanotube Composites for the Electrochemical Detection of Glutamic Acid using In Vitro Stroke Model

The significance of glutamic acid in healthcare as a neurotransmitter and food additive has prompted the scientific community to develop cost-effective non-enzymatic sensors with improved sensitivity, selectivity, and stability. Herein, we propose a non-enzymatic electrochemical sensor based on low-cost transition metal hydroxides to detect glutamic acid efficiently. An n-butanol/water interface-assisted synthesis strategy was employed as an initial step to tailor two-dimensional nickel hydroxide nanoflakes. To further improve electrical conductivity, nickel hydroxide nanoflakes were composited with a small amount of highly conductive multiwalled carbon nanotubes to form NH/MWCNT composite. The NH/MWCNT composite-modified sensor demonstrated excellent detection of glutamic acid with a detection limit of 72 nM, even in the presence of many interfering groups. The practicality of the sensor in medical technology was established by its ability to detect glutamic acid released by SH-SY5Y neural cells in both normal and oxygen–glucose deprivation-stressed conditions. As an extended application, the proposed sensor was also demonstrated to detect monosodium glutamate, a food additive found in commercially available food products. Finally, as a proof of concept, an in-house flexible sensor was fabricated to monitor glutamic acid released by human neural cells and monosodium glutamate in food samples. We anticipate that the present work will contribute to the development of cutting-edge third-generation non-enzymatic sensors for glutamic acid monitoring.

Sacrificial Template Method to Fabricate Highly Sensitive Porous Capacitive Pressure Sensor for Full Pulse Waveform Detection

Due to the recent advancements in sensing technology, skin mountable wearable devices have gained much attention due to their non-invasive usage and wearer comfort for health care monitoring. For instance, monitoring pulse waveform from the wrist arterial sites bears tremendous information about cardiovascular health and can show abnormalities such as hypertension or arterial fibrosis. Acquiring a high-quality pulse waveform from the wrist artery requires high-pressure sensitivity and fast response time. However, the need for building highly sensitive and low-cost fabrication of the sensors for subtle physiological monitoring is still challenging. Targeting these issues, this study presents a facile and cost-effective approach to realizing a flexible capacitive pressure sensor by sandwiching porous polydimethylsiloxane (PDMS) polymer functionalized by multi-walled carbon nanotubes (MWCNTs) fabricated by sacrificial template method for physiological monitoring. The fabrication steps for the dielectric layer involve mixing sucrose as the porogens and MWCNTs as the functionalizing material with PDMS followed by casting the mixture in a mold and curing of the PDMS. Subsequently, the sucrose particles are dissolved in water. The sucrose particles are easily dissolved in water leaving a highly uniform and porous structure behind. The dielectric layer is then sandwiched between two conductive textile based electrodes for physiological monitoring. The electromechanical tests were performed for different concentration of MWCNTs content in porous PDMS to obtain the best sensing performance. The champion sensor exhibits ultrahigh-pressure sensitivity of 2.41kPa-1 and a minimum detection limit of 1.4Pa in contrast to the sensor exhibiting only 0.31kPa-1 without addition of any MWCNTs. In addition, the pressure sensor shows a fast response time of 0.18s and excellent cyclic stability over 6000 cycles. The ultrahigh-pressure sensitivity comes from the addition of conductive MWCNTs filler that increases the dielectric permittivity. The highly porous structure of the polymer reduces the typical viscoelastic effects of polymer resulting in fast response time. The pressure sensor could detect arterial pulse waveform from the wrist artery with all the key characteristic points showing its promises for low-cost physiological monitoring. The detailed results will be discussed during the presentation.

Understanding Effects of Deep Traps on DC Surface Flashover Characteristics of Epoxy/MWCNTs-TiO2 Nanocomposites in a Vacuum

Surface flashover is likely to be triggered when a high electric field is applied due to its voltage being much lower than the breakdown voltage of either gas or solid, which restricts the development of advanced power electrical and electronic devices. To improve dc surface flashover performances in a vacuum and further explore the effects of deep traps on surface flashover, conductive multiwall carbon nanotubes (MWCNTs) and nonconductive nano-titania (TiO2) particles were incorporated into the epoxy (EP) matrix to tailor the surface deep trap level. Surface trap parameters, surface conductivity, surface charge density, and surface flashover voltage were calculated and measured. It indicates that surface flashover voltage improves by 23.07% and 14.45% compared to pristine EP when solely introducing MWCNTs or nano-TiO2 particles into the EP matrix, while it increases by 36.04% for C0.1T2 as simultaneously introducing both particles. When adding small amounts of particles, the surface charge transport is suppressed due to the introduction of bonded layers in the interfacial region, and the surface deep trap level is improved. As the surface deep trap level increases, charge transport and electron emission processes in the solid surface layer are hindered, which reduces the surface positive charge density and the distortion of the electric field and further results in the reduction of surface conductivity and the improvement of dc surface flashover voltage in a vacuum. The explanation for the effects of surface deep traps on surface flashover is essential for further improvements of surface flashover.

Facile production of binary polymer/carbonic nanofiller‐based biodegradable electromagnetic interference shield films with low electrical percolation threshold

AbstractInterference of electromagnetic (EM) radiation generated from different electronic gadgets produces noises diminishing their performance. So, shielding of EM interferences (EMI) is necessary to achieve noise‐free performance from electronic gadgets. In the present work, we have produced thermoplastic polyurethane (TPU)/polybutylene adipate‐co‐terephthalate (PBAT) based biodegradable binary polymeric blend and incorporated different carbonic nanofillers such as Vulcan XC‐72 conductive carbon black (VCB) and multiwalled carbon nanotube (MWCNT) into it employing solvent mixing and casting technique and studied the morphology of polymer blends, EMI shielding effectiveness in X‐band of the EM spectrum as well as mechanical performance, electrical performance, and biodegradability of polymer nanocomposites. The selective nanofiller distribution in the low viscous PBAT phase of the “co‐continuous” binary blend is found to achieve a “lower electrical percolation threshold” compared to neat polymer nanocomposites. For each of the TPU/PBAT/VCB and TPU/PBAT/MWCNT nanocomposites, electrical percolation threshold of around 12.5 and 5 wt% respectively has been achieved successfully. Nanocomposite sheets with a thickness of 1.0 mm and loading of 30 wt% of VCB and 15 wt% of MWCNT gave EMI shielding values of −25 dB and −28 dB respectively at a frequency of 8.4 GHz.

Engineering Interlaced Architecture of Pristine Graphene Anchored with 2-Amino-8-Naphthol 6-Sulfonic Acids for Printed Hybrid Micro-Supercapacitors with High Electrochemical Capability.

All-printed flexible micro-supercapacitors (MSCs) based on two-dimensional (2D) nanomaterials with in-plane interdigital configurations are regarded as promising miniaturized power source units, but they chronically suffer from self-aggregation and inadequate matching of electrode materials, thus resulting in inefficient electrolyte ions intercalation. Herein, an innovative multicomponent interlaced architecture essentially consisting of 2-amino-8-naphthol 6-sulfonic acid (ANS)-anchored pristine graphene and highly conductive multiwalled carbon nanotubes is reported. The assembled and optimized Gr@ANS electrodes offer sufficient absorption/desorption and redox-active sites, delivering a high areal capacitance of 33.7 mF/cm2 for screen-printed MSCs. Particularly, the well-modified Gr@ANS/CNTs-interlaced complex structure effectively prevents the usual restacking of the delaminated Gr@ANS nanosheets and maximizes ion accessibility in electrodes. Ascribed to the optimized electron-transferring kinetics, the achieved Gr@ANS/CNTs MSCs exhibit excellent capacitance (40.2 mF/cm2 and 18.8 F/cm3), simultaneously significantly increasing the rate capability of Gr@ANS MSCs (from 3.9 to 60.0%). Arising from the multicomponent synergism, the all-solid-state MSCs exhibit outstanding bending stability and cycling performance (73.8% after 10 000 charge/discharge cycles). The new charge reservoir engineering evidenced in graphene-based micro-supercapacitors would serve as a stepping stone toward the scalable manufacture of hybrid energy storage micro-devices.

Magnetic CuFe2O4 Nanoparticles with Pseudocapacitive Properties for Electrical Energy Storage.

This investigation is motivated by increasing interest in the development of magnetically ordered pseudocapacitors (MOPC), which exhibit interesting magnetocapacitive effects. Here, advanced pseudocapacitive properties of magnetic CuFe2O4 nanoparticles in negative potential range are reported, suggesting that CuFe2O4 is a promising MOPC and advanced negative electrode material for supercapacitors. A high capacitance of 2.76 F cm−2 is achieved at a low electrode resistance in a relatively large potential window of 0.8 V. The cyclic voltammograms and galvanostatic charge–discharge data show nearly ideal pseudocapacitive behavior. Good electrochemical performance is achieved at a high active mass loading due to the use of chelating molecules of ammonium salt of purpuric acid (ASPA) as a co-dispersant for CuFe2O4 nanoparticles and conductive multiwalled carbon nanotube (MCNT) additives. The adsorption of ASPA on different materials is linked to structural features of ASPA, which allows for different interaction and adsorption mechanisms. The combination of advanced magnetic and pseudocapacitive properties in a negative potential range in a single MOPC material provides a platform for various effects related to the influence of pseudocapacitive/magnetic properties on magnetic/pseudocapacitive behavior.

Investigation into a Lightweight Polymeric Porous Sponge with High Magnetic Field and Strain Sensitivity.

Recently, flexible sensors have gained significant attention due to their potential applications in soft robotics and biomimetic intelligent devices. However, the successful production of favorable flexible sensors integrated with high flexibility, sensitivity and excellent environment adaptability toward multiple external stimuli is still an enormous challenge. Herein, a lightweight polymeric porous sponge capable of detecting an external magnetic field and strain excitations is proposed by assembling a sodium alginate/chitosan (SA/CHI) porous sponge with micron carbonyl iron and nanoscale Fe3O4 magnetic particles (MPs). Based on the double network structure, the SA/CHI sponge possesses preferable mechanical strength and hydrophilicity, demonstrating its high flexibility and deformability. More importantly, the electrical response of the SA/CHI sponge sensors can display remarkable variation under external magnetic and mechanical stimuli due to their superior magnetic characteristics and electrical conductivity. Meanwhile, their sensing properties can maintain relatively stable recoverability and repeatability towards the periodic excitations and releases. Additionally, a potential mechanism is provided to investigate their stimuli-sensitive behavior. It is highly dependent on the microstructure variations in MPs and conductive multi-walled carbon nanotube (MWCNTs) networks. Due to its exceptional magnetic controllability and appropriate electrical sensitivity, the proposed sensor shows high potential in wearable multi-sensing electronics and intelligent transport devices.

Highly specific differentiation of MSCs into neurons directed by local electrical stimuli triggered wirelessly by electromagnetic induction nanogenerator

Transdifferentiation of mesenchymal stem cells (MSCs) into neurons provides a practical way for neurodegenerative diseases as alternatives to neural stem cells, but is confronted with challenges to get well-differentiated and mature neurons. In this work, a wirelessly triggered local electrical stimulation system was established to specifically induce neuronal differentiation from rat bone-marrow-derived MSCs (rBMSCs) by coupling a highly conductive and flexible multi-wall carbon nanotube (MWCNT) membrane with a rotating magnetic field. Without nerve-inducing factors, a nearly 100% yield of differentiated neurons was realised without the presence of astrocyte cells by the localized electrical stimuli mediated from electromagnetic induction nanogenerator. Neuronal functions were revealed by rapid spontaneous [Ca2+] i-transient peaks under neurotransmitter action. This novel therapeutic strategy for neurodegenerative disease was further demonstrated in vivo, where the successful neural differentiation of exogenous rBMSCs driven by external magnetic-filed accelerated the brain recovery. This wireless electric stimulation system shows promising effects on neuron differentiation and offers a new perspective in nerve repair without glial scarring.

Highly sensitive and stable 3D flexible pressure sensor based on carbon black and multi-walled carbon nanotubes prepared by hydrothermal method

High-performance piezoresistive sensors have the potential for human health monitoring applications. However, the conductive ink should add adhesive to ensure the hydrophobic carbon-based conductive material uniformly, which decrease the sensitivity. We fabricated a piezoresistive sensor without any adhesive polymer by introduced multi-walled carbon nanotubes (MWCNTs) and carbon black (CB) into the skeletons of the melamine sponge (MS) via a simple hydrothermal method. Due to the crosslinking effect, the microporous structure and strong adsorption of the of conductive MWCNTs and CB, the MWCNTs@CB sensor exhibits excellent performance: a sensitivity of 48.26 kPa−1 in the working range of 12.5 kPa–20 kPa, a response time of 15 ms, an low detection limit of 20 Pa, and performance stability (>250,000 loading cycles). This MWCNTs@CB flexible pressure sensor can detect physiological motions.

Enhancing anaerobic methane production in integrated floating-film activated sludge system filled with novel MWCNTs-modified carriers

Conductive materials can enhance anaerobic methane production by accelerating interspecies electron transfer between electroactive bacteria and methanogens. However, the daily loss or less specific surface area of small/big size of conductive materials always limits their application in anaerobic digestion. In this study, the conductive multi-walled carbon nanotubes (MWCNTs) (15 wt% and 20 wt%) were mixed with high-density polyethylene (HDPE) and novel conductive suspended carriers were prepared. Results showed the conductivity of the novel conductive suspended carriers increased by 1–2 orders of magnitude comparing with HDPE carriers, as well as the attached biomass improved from 3.93 g/m2 (HDPE carriers) to 5.82 g/m2 (15 wt% MWCNTs-modified carriers) and 6.67 g/m2 (20 wt% MWCNTs-modified carriers). Integrated floating-film activated sludge (IFFAS) filled with MWCNT-modified carriers showed significant advantages in chemical oxygen demand (COD) removal (removal efficiency increased by 3.6–37.2%) and methanogenic performance (cumulative methane increased by 12.28–62.91%) compared with the control reactor filled with conventional HDPE carriers when treating sodium propionate wastewater at the organic loading rates (OLR) of 11.3–26.3 kg COD/(m³∙d). SEM images and high-throughput sequencing results proved potential direct interspecies electron transfer (DIET) had been established successfully on the MWCNTs-modified carriers. The syntrophic electroactive bacteria (Geobacter, Thauera) and Methanotrix were enriched by 2.28–4.58% and 9.41–16.80% respectively owning to the addition of novel conductive carriers. This study proved IFFAS process filled with novel MWCNTs-modified suspended carriers showed great potential in establishing DIET to enhance anaerobic digestion in practical application.

Sensitive determination of uric acid at zinc layered hydroxide-sodium dodecyl sulphate-propoxur nanocomposites

An electrochemical chemical sensor for determination of uric acid (UA) with highly sensitive and widely working range was fabricated using zinc layered hydroxide-sodium dodecyl sulphate-propoxur (ZLH-SDS-PRO) nanocomposites modified with multiwall carbon nanotubes (MWCNT). Introduction of the ZLH-SDS-PRO as a conducting matrix has enhanced the conductivity of MWCNT. The ZLH-SDS-PRO/MWCNT morphology was characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), meanwhile the electrochemical behaviour of UA and K3[Fe(CN)6] at ZLH-SDS-PRO/MWCNT paste electrode was studied by square wave voltammetry (SWV) and cyclic voltammetry (CV), respectively. Under the optimized experimental conditions, the electrode established linear plot for UA from 7.0 µmol/L to 0.7 mmol/L (R2 = 0.9920) and the LOD was calculated to be 4.28 µmol/L (S/N = 3). The fabricated electrochemical electrode was successfully applied to urine samples and exhibit excellent stability and reproducibility, which made it worthwhile to be explored for analytical applications.

The fabrication and testing of a self-sensing MWCNT nanocomposite sensor for oil leak detection

Abstract Oil spillage, due to either direct or indirect accidents, can cause major environmental and economic issues if not detected and remedied immediately. In this study, the unique properties of carbon nanotubes have shown a substantial sensing capability for such a purpose when incorporated into a nanostructured composite material. A high-efficiency self-sensing nanocomposite sensor was fabricated by inserting highly conductive multi-walled carbon nanotubes (MWCNTs) into an elastomeric polymer substrate. The microstructure of the nanocomposite sensor was studied using scanning electronic microscopy and Raman spectroscopy. The response rate of the sensor was evaluated against different MWCNT concentrations, geometrical thickness and applied strains (causing by stretching). The results indicated that the response rate of the sensor (β) decreased with increasing MWCNT concentration and showed the strongest response when the sensor contained a 1.0 wt % concentration of MWCNTs. Additionally, it was found that the response time of the self-sensing nanocomposite sensors decreased in keeping with decreases in the sensor thickness. Moreover, when the sensor was subjected to strain, while immersed in an oil bath, it was found that the response rate (β) of the unstretched self-sensing nanocomposite sensor was significantly lower than that of the stretched one. The sensors given a 3% applied strain presented a response rate (β) ≈ 7.91 times higher than of the unstretched one. The self-sensing nanocomposite sensor described here shows good potential to be employed for oil leakage detection purposes due to its effective self-damage sensing capability and high sensing efficiency and low power consumption.