Multi-walled Carbon Nanotube Composites Research Articles

Hesperidin guided injured spinal cord neural regeneration with a combination of MWCNT-collagen-hyaluronic acid composite: In-vitro analysis

Restoring the lost bioelectrical signal transmission along with the appropriate microenvironment is one of the major clinical challenges in spinal cord regeneration. In the current research, we developed a polysaccharide-based protein composite Multiwalled Carbon Nanotubes (MWCNTs)/ Collagen (Col)/ Hyaluronic acid (HA) composite with Hesperidin (Hes) natural compound to investigate its combined therapeutic effect along with biocompatibility, antioxidant activity, and electrical conductivity. The multifunctional composites were characterized via FT-IR, XRD, SEM, HR-TEM, BET, C.V, and EIS techniques. The electrical conductivity and modulus of the MWCNT-Col-HA-Hes were 0.06 S/cm and 12.3 kPa, similar to the native spinal cord. The in-vitro Cytotoxicity, cell viability, antioxidant property, and cell migration ability of the prepared composites were investigated with a PC-12 cell line. In-vitro studies revealed that the multifunctional composites show higher cell viability, antioxidant, and cell migration properties than the control cells. Reduction of ROS level indicates that the Hes presence in the composite could reduce the cell stress by protecting it from oxidative damage and promoting cell migration towards the lesion site. The developed multifunctional composite can provide the antioxidant microenvironment with compatibility and mimic the native spinal cord by providing appropriate conductivity and mechanical strength for spinal cord tissue regeneration.

UiO-66/Carboxylated Multiwalled Carbon Nanotube Composites for Highly Efficient and Stable Voltammetric Sensors for Gatifloxacin

UiO-66/Carboxylated Multiwalled Carbon Nanotube Composites for Highly Efficient and Stable Voltammetric Sensors for Gatifloxacin

A 3D cross-linked hierarchical hydrogel E-skin with sensing of touch position and pressure

Artificial hydrogel electronic skin (E-skin) sensing systems have received considerable attention due to their ability in providing tactile perception. Recent advancements in hydrogel E-skin have allowed for simultaneous sensing of touch position and pressure through construction of sensor arrays. However, the fabrication process is complex, and the sensing resolution is limited by the size and number of array cells. Here, we report a multi-modal sensory E-skin based on a polyvinyl alcohol (PVA) hydrogel embedded with carbon nano-materials, which can recognize touch position and pressure simultaneously without constructing arrays. Combining the advantages of high electron transfer efficiency of 1D nanotube and 2D graphene nanosheet, the 3D hierarchical cross-linked polydopamine (PDA) modified reduced graphene oxide (rGO)/carboxylic multiwalled carbon nanotube (MWCNT-COOH) composites were proposed as a conductive filler, which was added by nano-doping to hydrogel substrate to gain an elastic modulus and stretchability of the hydrogel similar to that of human skin. Meanwhile, a surface-capacitive touch (SCT) system and piezoresistive technology were adopted to sense touch position and pressure due to the stability of conductive networks and the piezoresistive properties of carbon nanomaterials. Our E-skin device demonstrates superior sensing performance and provides a new direction for designing novel E-skin sensor devices.

Development of a chitosan-multi-walled carbon nanotubes composite for application in solid-phase adsorption toxin tracking of microcystins

Contamination of water and food with cyanotoxins poses human health risks, and hence the need for sensitive early warning tools to monitor these in water. A composite of glutaraldehyde-crosslinked chitosan and multi-walled carbon nanotubes (ChMWCNTs) was synthesised and tested for potential use as a solid-phase adsorption toxin tracking (SPATT) adsorbent for monitoring microcystins (MCs) in fresh water. The composite was characterised by Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller theory and scanning electron microscopy. Batch adsorption experiments to assess the effect of contact time, adsorbent dosage and initial microcystin-LR (MC-LR) concentration were conducted. The composite was found to be efficient in adsorbing MC-LR, showing 97% removal and a maximum adsorption capacity of 4.639 μg/g under optimised conditions of 5 μg/L of MC-LR, adsorbent dose of 0.03 g/5 mL and 30 min contact time. The adsorption kinetics were better explained by a pseudo-second-order model, inferring chemisorption adsorption. The isotherm data better fitted the Langmuir isotherm model, thus inferring monolayer surface adsorption. For desorption, 100% methanol was the most effective, with an efficiency of 84.71%. The composite effectively adsorbed and desorbed three congeners of MCs (–LR, –RR and –YR) when tested in raw dam water, regardless of its lower maximum adsorption capacity compared to those of other adsorbents used for similar purposes. Significance: Monitoring of microcystins is problematic in large reservoirs and rivers. Chitosan can be crosslinked and modified to enhance its adsorption properties. Composites of chitosan and carbon nanotubes efficiently adsorb and desorb microcystins. This study is possibly the first to apply a chitosan-based sorbent in solid-phase toxin tracking (SPATT) to be used as an early warning tool in passive monitoring of microcystins in water resources. Open data set: https://doi.org/10.6084/m9.figshare.20992291.v1

Highly sensitive and selective electrochemical sensor for simultaneous determination of gallic acid, theophylline and caffeine using poly(l-proline) decorated carbon nanotubes in biological and food samples

In this work, a novel, simple and reproducible poly(l-proline)/functionalized multi-walled carbon nanotube composite on glassy carbon electrode (poly(PRO)-MWCNTs/GCE) was developed as an electrochemical sensor for the simultaneous determination of gallic acid (GA), theophylline (TP) and caffeine (CAF) by differential pulse voltammetry (DPV).The sensing platform was optimized by experimental design and response surface methodology, using various factors affecting polymerization and detection, such as electropolymerization time and potential, and pH, respectively. As a result, the dispersion conditions were the mixing of 1.78 mg MWCNTs with 1.00 mL l-proline solution to 4.14 mg mL−1 (in SDBS 0.5%), followed by 21 min of sonication with electropolymerization by 16 cyclic scans. In addition, the final analysis was performed at a pH of 3.00 and prior accumulation at 0.350 V for 40 s.The electrochemical behavior of GA, TP and CAF on the optimized sensor was investigated. As a result, the electrode preserves and synergistically combines the properties of each modifier. This new electrochemical sensor showed superior electrocatalytic properties for the oxidation of GA, TP and CAF, which significantly improved the sensitivity of the three compounds.Under the optimized experimental conditions, the detection limits achieved by S/N were 0.03, 0.04 and 0.11 μmol L−1 for GA, TP and CAF, respectively. The analysis of real samples was successfully performed in human breast milk, tea, infusion of yerba mate, coffee, Coca-Cola zero and energy drink, showing good recoveries, ranged between 87 and 108%. The proposed sensor also showed good selectivity, repeatability and reproducibility, indicating feasibility and reliability.This is the first time that the l-proline monomer is used as a dispersant for MWCNTs and as a precursor for the in-situ polymerization of the proline polymer. Previously, the electropolymerizations were carried out with the monomer in solution rather than as an exfoliant of MWCNTs, where the polymer is electrosynthesized between MWCNTs rather than on them. In this way, the large specific surface area and strong adsorption ability of the nanomaterial are enhanced, and the ability to promote electron transfer reaction is increased, which provides enough effective reaction sites.

Fouling-resistant electrode for electrochemical sensing based on covalent-organic frameworks TpPA-1 dispersed cabon nanotubes

The key problem that limits the practical applications of nonenzymatic electrochemical sensors in biological media, is the biofouling and chemical fouling of electrodes due to the adsorption of biological molecules and oxidation (reduction) products. Electrode fouling will cause low accuracy, poor stability, and low sensitivity. Here, a simple and efficient antifouling electrode was demonstrated for electrochemical sensing based on covalent-organic framework (COF) TpPA-1 and carboxylic multi-walled carbon nanotubes (CNT) composites. COF TpPA-1 possesses abundant hydrophilic groups, which assisted the dispersion of CNT in water and formed uniform composites by π-π interaction. In addition, the introduction of CNT into the composites improved the electron transfer rate of COF TpPA-1. The antifouling interface was characterized by electrochemistry, contact angle measurement, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The electrode showed good chemical and bio-fouling resistant performance for the electrochemical detection of β-nicotinamide adenine dinucleotide (NADH) and uric acid (UA) in real serum samples.

Superhydrophobic surface of hybrid nanocomposites made of TiO2 and multi-walled carbon nanotubes: Photothermal ice removal performance and wear resistance

Superhydrophobic surfaces have gained significant popularity in industrial production due to their unique structure resembling lotus leaves. Achieving the mechanical stability of superhydrophobic surfaces and improving the self-cleaning and deicing effects have attracted critical research focus. This study incorporated a hybrid composite of titanium dioxide nanoparticles (TiO2) and multi-walled carbon nanotubes (MWCNTS), denoted as TiO2-MWCNTS, into an epoxy resin matrix. The hybrid composite was spray-coated onto the substrate and cured, resulting in a superhydrophobic surface with excellent wear resistance and deicing performance. By adjusting the mass ratio of TiO2 and MWCNTS, it was found that a 3:1 ratio exhibited a contact angle (WCA) of 159.8° ± 0.5°. Incorporating the TiO2-MWCNTS hybrid structure not only significantly improved the mechanical durability of the coating surface but also harnessed the outstanding photothermal conversion ability of carbon nanotubes, imparting excellent deicing capability to the coated surface. Therefore, this superhydrophobic surface holds great practical value for outdoor applications.

An enhanced field emission for display devices arises from the assembling of ZnO@MOF/MWCNTs

In this study, we propose a new, simple technique for raising the efficiency of field emission devices based on metal organic framework composites. Multi-walled carbon nanotubes (MWCNTs) and ZnO are used in the fabrication of metal-organicframeworks (MOFs) in this technique. This is explained by the composites unique structural structure, which offers a lot of easily available electro active sites, low surface work function, and improved electronic conductivity. One of the less complicated and more economical synthesis methods is used to synthesize the ZnO@MOF/MWCNTs composite. The material's precise morphological and structural features have all been investigated using Raman, FE-SEM, EDX, FTIR, and UV–Visible investigations. The ZnO@MOF/MWCNTs field emitter show impressive and stable field emission properties, such as a low turn-on electric field 0.50 V/μm and a high emission current density 219.15 mA/cm2.Our research revealed an easier way for boosting the electron field emission utilized in different field emission display systems that are based on MOFcomposites.

Treatment of Multi-Walled Carbon Nanotubes with Dichromic Acid: Oxidation and Appearance of Intercalation.

This work is dedicated to the study of the treatment of multi-walled carbon nanotubes (MWCNTs) with dichromic acid. The dichromic acid was formed by dissolving different concentrations of CrO3 in water. The effect of the concentration of dichromic acid on the change in texture characteristics, elemental composition, defectiveness, graphitization degree, and surface chemistry of MWCNTs was investigated using various analytical techniques, such as transmission electron microscopy, energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, and X-ray photoelectron spectroscopy (XPS). Testing of MWCNTs as electrodes for supercapacitors in 3.5 M H2SO4 solution was carried out using cyclic voltammetry. A decrease in the average diameter of CNTs after treatment was found. The EDX and XPS showed that the oxygen content on the surface of MWCNTs increased after treatment with dichromic acid. The formation of Cr2O3 after treatment with dichromic acid was detected by XPS. High angle annular dark field scanning transmission electron microscopy was used to confirm the intercalation of the chromium-containing compound between graphene layers of MWCNTs after treatment with dichromic acid. It was found that two different types of MWCNTs showed diverse behavior after treatment. The highest specific capacitance of the MWCNTs after treatment was 141 F g-1 (at 2 mV s-1) compared to 0.3 F g-1 for the untreated sample.

Stability of the Photoluminescent Response on Hydroxyapatite/Multi-Walled Carbon Nanotube Composites

The application of hydroxyapatite (HAp)/multi-walled carbon nanotube composites in the medical area as coatings in prosthetics has been widely used because the carbon nanotubes reinforce the mechanical properties of hydroxyapatite. Despite that, their photoluminescent properties have not been studied, nor has the effect of different amounts of multi-walled carbon nanotubes on this property or what happened with their response with time. This work demonstrated that the photoluminescent response of HAp and HAp/multi-walled carbon nanotubes functionalized with oxygen groups (OMWCNT) composites was stabilized over time. The evaluated parameters were: three different amounts of OMWCNT (15, 25, and 35 mg) and two different thermal treatment temperatures (250 and 400 °C); all the samples were measured twice, after preparation and over a year after. The results indicated that over time the photoluminescent response is stabilized due to the passivation of surface defects, independently of the amount of OMWCNT used and the thermal treatment. In the end, the photoluminescent properties of these composites will extend their utilization in the medical area or open the door to new applications.

Investigating the Effect of Hydroxyl Functionalized MWCNT on the Mechanical Properties of PMMA-Based Polymer Nanocomposites

Aims: The aim of this study was to evaluate the mechanical properties of polymer nanocomposites (PNCs) reinforced with multiwalled carbon nanotubes (MWCNT). Methods: Mixing MWCNT into the polymer at very small propositions can enrich the mechanical properties of the polymer nanocomposites. Testing Specimen fabricated with 0.1wt%, 0.5wt%, 1wt% mixing ratios using extrusion and injection molding process. Computational analysis was performed through the square RVE model and analyzed with finite element analysis (FEA) using DIGIMAT simulation tool. The specimen was evaluated by ASTM D3039 for tensile strength and ASTM D7264 for flexural. Results: The simulated results were compared with experimental results. Scanning electron microscopy(SEM) was performed to evaluate the dispersion state of nanotubes in the matrix. Conclusion: The impactful improvement in mechanical properties is shown in the results after addition of functionalized MWCNTs (f-MWCNT) compared to pure polymer and non- functionalized MWCNT composites.

Adsorptive removal of diclofenac sodium from aqueous solution by highly efficient metal organic framework (UiO-66)/multi-walled carbon nanotube composite.

In the current study, synthesis and use of a novel adsorbent (composite in nature) are presented for treatment of one of the most commonly found pharmaceutical compound, viz, diclofenac sodium (DCF) in waste water. Synthesis of the composite adsorbent was done by hydrothermal method metal organic framework (MOF) based on Zr metal and multi-walled carbon nanotube (MWCNT). The composite adsorbent is termed as UiO-66/MWCNT. The confirmation of successful synthesis of the adsorbent is done with the help of sophisticated characterization techniques like FTIR, XRD, zeta potential analyser, and SEM. The synthesized composite adsorbent is found to have good adsorption capacity for DCF. The experiments related to the process of adsorption were done in batch mode and the significance of various operating parameters affecting the specific uptake of DCF. Maximum adsorption is observed at 3 pH (acidic condition) when the initial concentration of DCF and adsorbent dose was 30 mg/L and 100 mg/L, respectively. The Langmuir isotherm model best describes the process of adsorption with a maximum adsorption capacity of 256.41 mg/g. Experimental results obtained through the studies conducted related to the kinetics displayed that the process followed pseudo-second order model, and intraparticle studies suggested that diffusion through pores controls the rate. Thermodynamic studies suggest that the adsorption of DCF on UiO-66/MWCNT was completely spontaneous with ΔH = -22.089 kJ/mol. The possible mechanism for the adsorptive removal of DCF through UiO-66/MWCNT as found from this study is electrostatic interaction.

Room temperature operated flexible La-ZnO/MWCNTs sensor for ppb level carbon monoxide detection

The advancement of gas sensors with ppb level concentration experiences profound challenges. In this research, Lanthanum (La)-Zinc Oxide (ZnO)/multi-walled carbon nanotubes (MWCNTs) composites were successfully fabricated and loaded on a flexible polyimide substrate where interdigitated electrodes (thickness: 300 µm and spacing: 300 µm) were prepared using a laser carbonation technique for room temperature (RT) carbon monoxide (CO) gas detection. The synthesized composites were characterized using scanning electron microscopy, energy dispersive x-ray spectroscopy, UV–visible spectrophotometry, x-ray diffraction, and Fourier transform infrared spectroscopy. When compared to the La-ZnO composite, the addition of MWCNTs on the synthesized composite-based sensor exhibited ∼8 times higher response than La-ZnO to 100 ppm CO at 27 °C. The response of the La-ZnO/MWCNTs composite sensors to 20 ppm CO was tested at six different relative humidity (RH) levels ranging from 0% to 90% in the increments of 20% RH. These sensors exhibited humidity tolerant properties, as evidenced by their responses to different humidity levels. Even when exposed to 90% RH, the sensor only showed ∼13% reduction in response compared to 0% RH, indicating that it is a humidity tolerant sensor. Furthermore, the La-ZnO/MWCNTs sensor has excellent selectivity and can detect low CO concentrations of 100 ppb. As a result, the proposed high-performance flexible sensor has a lot of potential for use in wearable devices to sense CO gas at RT for trace level detection.

ZnO/f-MWCNT as a potential candidate for supercapacitive energy storage and piezoelectric energy generation

Zinc oxide/ functionalized multiwalled carbon nanotube (ZnO/f-MWCNT) composite was synthesized in two simple steps. In the first step, MWCNT was functionalized using acid refluxing method and in the second step, ZnO/f-MWCNT composite was synthesized in situ via hydrothermal route. Next, possibility of the ZnO/f-MWCNT composite as a hybrid energy storage device was explored through detailed electrochemical and other required investigations. Aiming to real-life applications, a symmetric supercapacitor device was also fabricated followed by detailed performance evaluation. In the last part, energy harvesting possibilities of the ZnO/f-MWCNT composite through the fabrication of a piezoelectric nanogenerator (PENG) was also explored. To do so, ZnO/f-MWCNT/ polyvinylidene fluoride (PVDF) composite films with varying wt% of the filler (i.e. ZnO/f-MWCNT) were prepared. The structural, morphological, compositional, electrochemical and electrical attributes of both the materials were thoroughly investigated. Highest specific capacitance obtained from this ZnO/f-MWCNT electrode was 794 F/g (at 1 A/g) with a power density of 4152 W/kg (at 50 A/g). The PENG device yielded an open circuit voltage of ∼80 V with a power density of 72 kW/m3.

Investigation of finned heat sinks with PEG-6000/EG and PEG-6000/MWCNT composite phase change material for thermal management application

Present study reports the thermal performance of various cross finned heat sinks involving PEG-6000/EG and PEG-6000/MWCNT composites for thermal management applications. The performance of various heat sink configurations namely, heat sink with one cavity (HSOC), heat sink with four cavities (HSFC), heat sink with nine cavities (HSNC), and heat sink with sixteen cavities (HSSC) are analyzed for different heat flux values (q” = 1.7 kW/m2 to 2.4 kW/m2). Polyethylene glycol-6000 (PEG-6000) is considered as phase change material (PCM); while expanded graphite (EG) and multi-walled carbon nanotubes (MWCNT) with varied weight concentrations (0.5, 1.0 and 2.0 %) are used to prepare composite PCM (CPCM). The characterization has been made to access various thermophysical properties and thermal stability of CPCMs. The thermal performance of heat sinks involving CPCM is estimated by analyzing the enhancement ratio and the modified Stefan Number. A maximum enhancement of 55.80 % in thermal conductivity is achieved for CPCM involving PEG-6000 and 2.0 % MWCNT compared to only PEG-6000. The maximum value of enhancement ratio is found to be 1.37 and 1.18 for HSFC with with PEG-6000 and 2.0 wt% EG at q” = 1.7 kW/m2 and q” = 2.4 kW/m2, respectively. The minimum value of modified Stefan number (St) is found to be 8.25 and 11.65 at q” = 1.7 kW/m2 and q” = 2.4 kW/m2, respectively for PEG-6000 and 2.0 wt% EG. The findings suggest that the HSFC with PEG-6000 and 2.0 wt% EG CPCM has the potential to enhance the thermal performance of heat sinks and can be incorporated for efficient thermal management of electronic components.

Synthesis of carbon nanotube-iron oxide composites via combustion waves for hybrid Li-ion battery anodes

The design and synthesis of suitable transition metal oxide (TMO) with carbonaceous material are crucial to produce high-performance anodes for Lithium-ion batteries (LIBs). Here, we show a facile synthesis method for iron oxide and carbon nanotube (CNT) composite via CNT-guided combustion waves. The combustion waves propagate through a freestanding film composed of multi-walled CNTs (MWCNTs), iron nitrate, and combustible nitrocellulose, synthesizing the composite in one-pot within a few seconds. The resulting composite consists of MWCNT networks encapsulating iron oxide submicron particles (CFs). The composite electrode employing optimized CFs provides exceptional initial specific capacity and rate capability (792 mAh/g at 0.1C and 588 mAh/g at 5C) and an increased capacity of 1215 mAh/g after 500 charge–discharge cycles at 1C. The morphological and electrochemical characterization reveal pulverized nanoparticles encapsulated within MWCNT networks, entailing hybrid capacities of redox conversion and pseudocapacitance. This facile synthesis method for TMO–MWCNT composites provides a feasible family of low-cost composite electrodes for high-performance LIBs.

Ag Sputter-Deposited on MnO2-Carbon Nanotube Nanocomposites as Electrocatalysts for Oxygen Reduction Reaction in Alkaline Media

As energy demand increases, new energy conversion methods are also sought. In this study, two MnO2 and multiwalled carbon nanotube (MWCNT) composites were prepared and decorated with silver using magnetron sputtering, to evaluate their electrocatalytic activity towards the oxygen reduction reaction (ORR). Three nominal thicknesses of Ag layers were used, 5, 10 and 20 nm. The physicochemical characterisation was carried out using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, as well as X-ray photoelectron spectroscopy. The substrate materials (MnO2-MWCNT) were also investigated by X-ray diffraction analysis. The electrochemical studies of the ORR revealed that the activity and stability of the composite catalysts depend on the substrate material and the Ag layer thickness.

Near‐Room‐Temperature Thermoelectric Performance Enhancement Via Phonon Spectra Mismatch in Mg3(Sb, Bi)2‐Based Material by Incorporating Multi‐Walled Carbon Nanotubes

AbstractAlthough a high figure of merit (zT) over a wide range of temperatures has been shown in n‐type Zintl Mg3(Sb, Bi)2, further improvement of its near‐room‐temperature performance is still required to promote its application in next‐generation thermoelectric coolers and power generators. Here, a novel strategy of phonon spectra mismatch for enhancing the thermoelectric performance of Mg3(Sb, Bi)2 is reported by incorporating multi‐walled carbon nanotubes (MWCNT). The introduction of very small amounts of MWCNT generates a large interfacial thermal resistance and thus significantly reduces the lattice thermal conductivity of the resulting composites, while maintaining a high power factor. As a result, a zT of ≈1.5 at 573 K and an average zT of 1.14 between 323 and 573 K can be achieved in the 0.5 wt% MWCNT composite. Moreover, a high conversion efficiency of ≈8.1% under a temperature difference of 283 K is realized in a resulting single‐leg device, making it a promising candidate material for low‐grade heat recovery. This study provides not only a material with a high near‐room‐temperature zT but also a unique insight into the design of high‐performance thermoelectric materials via compositing to exploit the large difference in phonon spectra between the components of the composite.

Enhanced thermoelectric properties of bismuth telluride (Bi2Te3) and multiwall carbon nanotube (MWCNT) composites

Solid solutions based on bismuth telluride are the traditional thermoelectric materials that are commercially utilized in the industry close to room temperature applications, where energy scavenging is a big challenge due to low quality and energy density. However, their broader applications are still limited due to low efficiency. The focus of the present work is to enhance the energy conversion efficiency of Bi2Te3 by mixing one-dimensional (1D) multiwall carbon nanotubes (MWCNTs) via facile powder processing by synergistically utilizing the nanostructuring and quantum confinement effects. Thus, different vol% of MWCNTs ranging from 0.5, 1.0, 1.5, and 2 were uniformly dispersed in a fine powder of Bi2Te3 that was ball milled from course Bi2Te3 in an inert environment. The coarse Bi2Te3 and fine composite powders were consolidated in a spark plasma-sintering furnace at ∼400 °C under uniaxial pressure of ∼40 MPa. Thermoelectric properties of Bi2Te3-based MWCNTs composites were evaluated in the temperature range from ∼300 to ∼525 K. The electrical conductivity of 1.5 vol% MWCNT composite has significantly enhanced from pristine Bi2Te3. This increase indicates that electrical transport dominantly involves a percolating network of MWCNTs. The concomitant increase in the Seebeck coefficient of 1.5 vol% Bi2Te3 composite suggests the enhanced energy-dependent scattering of charge carriers. Consequently, a substantially improved power factor is observed for the composite. The thermal conductivity of all the composites decreases, and considerable reduction is achieved for 0.5 vol% due to enhanced phonon scattering through nanostructuring and uniform distribution of the nanotubes. Hence, the significant decrease in thermal conductivity with improved power factor leads to substantial improvement in the thermoelectric figure of merit of 1.5 vol% Bi2Te3 composite from pristine Bi2Te3.

Robust 3D porous superhydrophobic foam with excellent photothermal effect and Joule heating effect for efficient all-weather cleanup of highly viscous crude oil spills

Crude oil spill is difficult to deal with and still a global challenge due to its high viscosity. Developing foams with excellent mechanical properties, photothermal effect and Joule heating effect simultaneously to achieve crude oil all-weather recovery is desirable. Here, 3D porous foams were successfully fabricated by the composite of polydimethylsiloxane (PDMS) and multi-walled carbon nanotubes (MWCNT) by a combination of sacrificial template method and laser etching treatment. Benefiting from the low surface energy of PDMS itself and the micro-nano structures constructed in the preparation, the obtained foams exhibit excellent superhydrophobic and superoleophilic properties (WCA of 157° and OCA of 0°). Significantly, MWCNT do not exist as a coating around the foam surface, but as the main component constituting the foam skeleton, so the foam shows excellent mechanical property, low temperature resistance, high temperature resistance, salt resistance and abrasion resistance. Moreover, taking the advantage of the addition of MWCNT, the foam shows excellent photothermal effect requiring 1 sun irradiation to attain a temperature of 60.7 ℃ after 4 min and a stable temperature of 71.6 ℃ after 10 min, and Joule heating effect requiring only 9 V voltage to attain a temperature of 64.5 ℃ after 1.5 min and a stable temperature of 91.1 ℃ after 10 min, respectively. Besides low viscosity oil–water separation, it can achieve rapid crude oil spill recovery under the photothermal effect or Joule heating effect. The combination of the two effects can realize the coupling effect and achieve high-efficiency all-weather high viscosity crude oil recovery, thus making the foam more practical. This foam is expected to be an ideal material for all-weather dealing with oil spills.