Presence Of CNT Research Articles

Binder-Free CNT-Modified Excellent Electrodes for All-Vanadium Redox Flow Batteries.

Electrodes are one of the key components that influence the performance of all-vanadium redox flow batteries (VRFBs). A porous graphite felt with modified fiber surfaces that can provide a high specific activation surface is preferred as the electrode of a VRFB. In this study, a simple binder-free approach is developed for preparing stable carbon nanotube modified graphite felt electrodes (CNT-GFs). Heat-treated graphite felt electrodes (H-GFs) are dip-coated using CNT homogeneous solution. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) results conclude that CNT-GFs have less resistance, better reaction currents, and reversibility as compared to H-GF. Cell performances showed that CNT-GFs significantly improve the performance of a VRFB, especially for the CNT-GF served in the positive side of the VRFB. CNT presence increases the electrochemical properties of the graphite electrode; as a result, reaction kinetics for both VO2+/VO2+ and V3+/V2+ are improved. Positive CNT-GF (P-CNT-GF) configured VRFB exhibits voltage efficiency, coulombic efficiency, and energy efficiency of 85%, 97%, and 82%, respectively, at the operating current density of 100 mA cm-2. At high current density of 200 mA cm-2, the VRFB with P-CNT-GF shows 73%, 98%, and 72% of the voltage, coulombic, and energy efficiencies, respectively. The energy efficiency of the CNT-GF is 6% higher when compared with that of B-H-GF. The VRFB with CNT-GF can provide stable performance for 300 cycles at 200 mA cm-2.

Synthesis of in situ Generated Cu−CNT Hybrid Nanofluid and the Study of Their Thermo‐physical Properties

AbstractIn recent years, numerous investigations have been carried out in heat transfer applications for CNT nanofluid as it possesses a high thermal conductivity compared to conventional fluids. Hydrophobicity of CNT poses a challenge to disperse CNT in polar basefluid. Surfactants can solve this issue up to a certain extent only but have some associated disadvantages such as foam formation, stickiness and viscosity enhancement responsible for an increase in power required to pump Nanofluid in heat transfer devices. This work presents preparation of a hybrid nanofluid as an alternative. Cu−CNT hybrid nanoparticles were generated in this research using in‐situ preparation of Cu nanoparticles in the presence of CNT and dispersion in double distilled water without addition of surfactant to produce a stable nanofluid. FESEM with EDX confirms copper nanoparticles present on outer surface of MWCNT and Raman spectroscopy confirmed the covalent functionalization. Spectral analysis, Zeta potential, and DLS were used to evaluate the dispersibility of Cu−CNT hybrid nanofluid. The results showed that the samples were extremely stable, with maximum stability of about 168 days. XRD pattern of Cu−CNT hybrid nanoparticles confirmed the existence of Cu and CNT. Nanofluid demonstrated a minor increase in density and viscosity compared to basefluid water due to addition of nanoparticles. An increase in thermal conductivity was also observed, which is critical for heat transfer applications.

Effect of annealing and carbon nanotube infill on the mechanical and electrical properties of additively manufactured polyether-ether-ketone nanocomposites via fused filament fabrication

The light-weight, high-strength poly-ether-ether-ketone (PEEK) and its composite materials are the ideal candidate for a plethora of engineering applications. However, the inherent high viscosity and melting temperature of PEEK pose great challenges for the extrusion-based 3D printing process, leaving a wide knowledge gap on the properties and functionalities of novel PEEK-based composites. In this work, the PEEK/CNT composite filaments with different CNT content ranging from 1 to 7 wt% are prepared by single-screw extruder and subsequently printed with a custom-made high temperature 3D printer. The effects of CNT content and annealing on the mechanical strength and electrical conductivity of the 3D printed parts are investigated in detail. The tensile test result shows that the presence of CNT significantly enhances the mechanical strength of the composite. With 7 wt% CNT content, the maximum tensile strength and elastic modulus reaches 107.7 MPa and 1908.0 MPa, respectively, which amounts to a rise of 27.4% and 17.0% compared with the neat PEEK sample. The annealing treatment is similarly effective in strengthening the printed composites. The addition of CNT is also found to greatly improve the electrical conductivity to the PEEK, reaching 101 S/m for 7 wt% CNT. With such superior electrical conductivity, the printed PEEK/CNT composite sample exhibits outstanding electromagnetic interference (EMI) shielding performance, reaching 32.4 dB. However, additional annealing treatment decreases the electrical conductivity as wells as EMI shielding performance. Such decrease is mainly attributed to the growth of the crystals during annealing, which expels the CNTs to the grain boundaries and leads to remarkable agglomeration, which disconnects the pervasive conductive networks. The finding in this work can provide insights on the new designs of PEEK composite feedstock materials and cultivate new 3D printing strategies targeted specifically for highly-functional, high-strength novel composites.

(Invited) A Carbon Nanotube Binding Bis(pyrenylstyryl)Bodipy-C60 Nano Tweezer: Formation and Photoinduced Charge Separation in Supramolecular C60-Bodipy-SWCNT Triads

Electron donor-acceptor hybrids comprised of single-wall carbon nanotubes (SWCNT) are promising functional structures having direct applications in energy conversion schemes and molecular optoelectronics. For building such hybrids and exfoliation of SWCNTs, the p-stacking ability of large aromatic compounds such as pyrene is one of the commonly employed approaches. Often, the desired donor or acceptor entities are functionalized to carry one or more pyrene entities and allowed to interact with CNTs. As a suitable electron donor, BODIPYs stand out owing to their ease of structural modifications and rich spectral and redox properties. Consequently, several donor-acceptor conjugates comprised of BF2-chelated dipyrromethene, BODIPY, and the well-known electron acceptor, C60 have been developed. In the present study, we have newly synthesized a nano tweezer comprised of covalently linked BODIPY-C60 carrying two pyrenylstyryl arms, 1. Compound 1 is further allowed to interact with SWCNT(6,5) and SWCNT(7,6) to form the supramolecular C60-BODIPY-SWCNT triads. Upon spectral, electrochemical, and computational characterization, pump-probe spectroscopic studies covering a wide femto-to-millisecond time scale have been performed to establish the occurrence of photoinduced charge separation. The presence of CNT prolonged the lifetime of the charge-separated states revealing the success of the present molecular design strategy for energy harvesting applications. D’Souza, F.; Sandanayaka, A. S. D.; Ito, O. ‘SWNT-Based Supramolecular Nanoarchitectures with Photosensitizing Donor and Acceptor Molecules’ Phys. Chem. Letts. 2010, 1. 2586-2593.B. KC, G. N. Lim, and F. D’Souza, ‘Accelerated Charge Separation in Graphene Decorated Multi-Modular Tripyrene-Subphthalocyanine-Fullerene Donor-Acceptor Hybrids,’ Angew. Chem. Int. Ed. 2015, 54, 5088-5092.Barrejon, L. M. Arellano, F. D’Souza, F. Langa, ‘Bidirectional charge transfer in carbon-based hybrid nanomaterials’ Nanoscale, 2019, 11, 14978-14992. Figure 1

Segregated structure of poly (vinylidene fluoride-co-hexafluoropropylene) composites loaded with polyaniline@carbon nanotube hybrids with enhanced microwave absorbing properties

Polyaniline@carbon nanotube (PAni@CNT) hybrid with electrical conductivity of 5.2 S/cm was successfully prepared by inverted emulsion polymerization of aniline in the presence of CNT dispersed in toluene assisted by cetyl-trimethyl ammonium bromide (CTAB). Conductive composites based on poly (vinylidene fluoride-co-hexafluoropropylene) (PVDFH) loaded with different amounts of PAni and PAni@CNT were prepared by dry-blending the powders in a ball-mill followed by hot compression molding. This procedure resulted in a segregated structure of the fillers, as indicated by scanning electron microscopy (SEM). The composite with 10 wt% of PAni@CNT (9.5: 0.5 wt%) hybrid exhibited electrical conductivity near 10−3 S/m and outstanding electromagnetic wave (EMW) attenuation. Indeed, reflection loss (RL) of − 34 dB (more than 99.9% EMW attenuation) at 11.7 GHz and effective absorption bandwidth (EAB) frequency with RL < −10 dB (more than 90% EMW attenuation) corresponding to 7.3 GHz were observed for this composition with thickness of 3 mm. A comparative analysis of measured and calculated RL was conducted. Considering the simple and cost effective preparation procedure, these composites loaded with 5 wt% and 10 wt% of the hybrid material are promising alternatives for developing efficient microwave absorbing material for both military and civil applications.

RETRACTED: Improve the rheological and thermal performances of the antifreeze liquids for cooling the batteries and radiators in automobiles via provide a new hybrid material composed from Carbon Nanotubes in Ethylene Glycol/Propylene Glycol

A new antifreeze hybrid nanofluid is developed in the present study. The hydrodynamic and thermal properties of the base fluids, such as water and Ethylene glycol are improved via examining the Nanoparticles. The final achieved nanofluid will be used for the cooling batteries; however, it might be applied for similar mechanical/ electrical systems such as through the radiators. The Carbon nanotubes are examined as dispersed nanoparticles. At first, an experimental part of producing the new mixture involving homogenizing and predicting the thermo-physical properties is presented. The numerical section will be reported regarding the heating/cooling simulations for the batteries. The proposed nanofluid in battery cooling systems dropped the battery temperature in different conditions. To investigate the effects of nanofluids, the energy equation was solved along with the energy source term arising from electrochemical reactions and ohmic losses. The temperature distribution inside the battery indicated a reduction in the maximum battery temperature when CNT nanoparticles were loaded. At a 50% state of discharge, the average battery temperature was 5.8°C lower when nanoparticles were CNT was loaded into EG + W. As the amount of state of discharge increased, the effect of the CNT presence intensified so that at a level of 95%, the temperature dropped by 6.9°C.

In-situ synthesis of CNT/UiO-66-NH2-based molecularly imprinted nanocomposite membranes for selective recognition and separation of sulfamethoxazole: A synergistic promotion system

Sulfamethoxazole (SMX) is a widespread organic contaminant that threatens the ecological environment and human health. Therefore, it is of great significance to develop an effective method for selective separation of SMX from the aquatic environments. Herein, a novel in-situ synthesis of CNT/UiO-66-NH2 based molecularly imprinted nanocomposite membranes (CUMIMs) is designed for selective removal of SMX. The CNT/UiO-66-NH2 nanocomposite is prepared through in-situ growth of MOFs in the presence of CNT. The CNT around the MOFs can effectively avoid the aggregation of CNT/UiO-66-NH2 nanocomposite and introduce unique properties into the PVDF/PVA membrane, which simultaneously benefit in both hydrophilicity and water flux. More importantly, the well dispersed CNT/UiO-66-NH2 nanocomposite with huge specific in the membrane can facilitate the selectivity toward SMX. The selective separation performance of CUMIMs is evaluated by static adsorption and permeselectivity experiments. The results showed that the synthesized CUMIMs afford an ideal rebinding selectivity (αSMX/SMM = 2.01, αSMX/TC = 4.34, and αSMX/CIP = 4.65) and permselectivity factor (β = 2.15) toward SMX. The presented strategy on CUMIMs fabrication would potentially enrich the application of CNT/MOFs-based molecularly imprinted nanocomposite membrane in the field of contaminant separation.

Hybrid nanocellulose/carbon nanotube/natural rubber nanocomposites with a continuous three‐dimensional conductive network

AbstractIn this study, the hybrid effect of nanocellulose/carbon nanotube (NCC/CNT) reinforcement on natural rubber (NR) nanocomposites was investigated. To this end, three series of NR nanocomposites were prepared: NCC/NR, CNT/NR and NCC/CNT/NR. First, the nanocomposites morphology and the filler–rubber interactions were studied using scanning electron microscopy (SEM) and the swelling behavior in toluene, respectively. The results showed that the presence of NCC improved the NCC/CNT hybrid filler dispersion forming a 3D network, while the presence of CNT increased the filler–matrix interaction. The curing results also confirmed that the degree of crosslinking increased when hybrid fillers were used, but the curing time was not modified. In addition, it was observed that using a NCC/CNT hybrid system led to superior mechanical properties, dynamic mechanical properties and thermal conductivity than each material used separately. When 10 phr hybrid filler (with a filler ratio of 1) was added to NR, the tensile strength, modulus at 300% elongation (M300), storage modulus at 10% strain and thermal conductivity were all increased by 57%, 137%, 120%, and 30%, respectively. The results also showed that the NR nanocomposites properties can be controlled by tuning the NCC/CNT filler ratio.

Development and characterization of (ZnO)0.90(CNT)0.10 thick film for photovoltaic application

In this study we prepared (ZnO)0.90(CNT)0.10 thick film by screen printed technique which is very economical and sophisticated method. ZnO and highly active powdered CNT have been used as basic source of materials under the optimum conditions for preparing the best quality screen printed film have been found. The prepared film has been investigated by X-ray diffraction (XRD), Diffused reflectance spectroscopy and DC conductivity measurement for structural, morphological, optical and electrical characteristics. XRD revealed the presence of CNT with hexagonal structure along a strong (101) orientation of plane. SEM micrograph depicts densely covered ZnO particles by powdered CNT bundles. Direct optical band gap transition of the ordered of 3.15 eV. Negative temperature coefficient of resistance of the sample was confirmed with activation energy 0.23 eV by using two probe method.

Combination of iodine-deficient BiOI phases in the presence of CNT to enhance photocatalytic activity towards phenol decomposition under visible light

In this work, we have prepared BiOI/CNT composites by hydrothermal method and studied the impact of CNT and hydrothermal treatment conditions (temperature and time) simultaneously on phenomena such as crystallization. The samples were studied using X-ray Diffraction (XRD), nitrogen sorption (Brunauer–Emmett–Teller (BET) specific surface areas), Scanning Electron Microscopy assisted with Energy Dispersive X-Ray spectroscopy (SEM-EDX), High Resolution Transmission Electron Microscopy (HRTEM), UV–vis Diffuse Reflectance spectroscopy (DRS), Raman spectroscopy and photoluminescence spectroscopy (PL). The different heat treatments applied and varied amount of CNT was found to have a profound effect on the structural, morphological, compositional and optical properties of the prepared composites. The distinguishable changes in the above-mentioned properties were clearly visible for the samples prepared at higher temperature and longer duration (150 °C, 6.30 h). Surprisingly, the presence of other phases of BiOI, such as Bi7O9I3, Bi4O5I2, Bi5O7I, also co-existed at the same time, although in low amount. Finally, for the study, the photocatalytic efficiency of the prepared samples was tested for phenol and RhB, as model pollutants, under visible light irradiation for 240 min and 120 min, respectively. The results revealed that the composites prepared at higher temperature with longer duration showed superior performance for the photodegradation of phenol and RhB. Additionally, the composites performed better than their respective reference samples in each case. Interestingly, the introduction of CNT promoted the crystallinity in the composites and promising results for the removal of phenol and RhB were achieved by the use of low power ordinary visible lamps.

Thermal Modelling and Multi Decision Making Optimization of EDM of Non Conductive SiC-CNT Ceramic Composite Used for Li-ion Battery and Sensor

In this research work the thermal modeling of a nonconductive Silicon carbide Ceramic matrix composite (CMC) machined by Die Sinking Electric Discharge Machining (EDM) has been done. Though SiC is a non-conductive material but the presence of CNT makes it a conductive material which can be machined with EDM. The modeling procedure carried out by considering some realistic approach like Gaussian heat Flux, Specific Discharge Energy, Variable Latent heat etc. For this analysis a 2D continuum has been designed as work domain. By simulating the work domain model by a Finite Element Analysis (FEA) Software (COMSOL), material removal rate (MRR) has been estimated with variable thermal properties. Parametric analysis of effect of Variable Specific heat on MRR by considering different current, Voltage and Pulse-On time has been performed. The effect of different input parameters (peak current and Pulse-on time) on Crater geometry has been done. A new concept of Specific discharge energy has been introduced during modelling to make it a more realistic model which can also be used as electrode support for electrochemical energy devices as Polymer Electrolyte Membrane Fuel Cells on Li-ion battery. Desirability analysis has been done to get an optimize set of input parameters for I= 3A, V=30V, Ton= 75 µs for machining ceramic matrix composite by EDM. The optimized MRR at this setting is 7.25 mm3/min whereas PFE is 87%. The experimental analysis has been also performed to strengthen the thermal and mathematical modelling.

Synthesis and characterization of carbon nanotubes over hollow glass microspheres and its nanocomposites

Hollow Glass Microspheres (HGM) is now challenging reinforcement for making low density composites with high stiffness, good electrical and mechanical properties. Carbon nano tubes when reinforced homogenously in the matrix it enhance properties of the composites to a commendable range. These CNTs are grown over HGM using chemical vapor deposition (CVD) technique at 600 °C temperature. Initially HGM were nickel coated by electroless deposition technique using nickel sulphate as the source of metal in the alkaline bath and then the catalyst coated HGMs were exposed to the mixture of acetylene and nitrogen gas at various temperatures to form CNT over HGM. Scanning Electron Microscopy (SEM) images explore the quality and dimensions of CNT. Other characterizations such as XRD, Raman Spectroscopy confirm the presence of CNT. Using these coated HGM as fillers in Epoxy, composites were fabricated and the same was characterized for compression using UTM and DMA using DMA analyzer.

Electrochemical synthesis and structural characterization of nanostructured V[formula omitted]O[formula omitted].nH[formula omitted]O on CNTs coated/uncoated carbon felt composite

Amorphous V2O5.nH2O nanostructures (Ns) on CNTs coated/uncoated carbon fibre felt are very attractive electrodes for various electrochemical devices. In present article, we report the morphological and structural characterizations of electrodeposited V2O5.nH2O (denoted as δ-V2O5) phase on defective CNTs coated/uncoated graphitic carbon fibre felt using micro-Raman scattering, TGA curves, SEM and XPS techniques. Using electrochemical methodology, we obtained a highly stable superficial hydrated V2O5.nH2O (n ∼ 0.5) Ns on the surface of bare carbon fibre felt and defective CNT/carbon fibre felt composite. The intercalated hydroxide/H2O bonds are stable till 350°C temperature on both CNTs coated/uncoated felt substrates, which can be extracted from V2O5.nH2O structure using high laser power (≥ 10 mW). After de-hydration of V2O5.nH2O Ns, the local structural phase inclined to ε-V2O5. The surface morphological modification from flat to wrinkle like patterned of V2O5.nH2O Ns depends on electrodeposition parameters (current and time), while the CNT provokes the formation of a V2O5.nH2O layer on CNT/felt fibres with larger degree of roughness, hydration and thickness than in case of bare felt fibres. The proportion of oxidation-state (V+5∕+4∕+3) is barely influenced by CNT presence. Moreover, the electrodeposited V2O5.nH2O layer on graphite felt occurs heterogeneously on the carbon fibre electrode surface, unlike CNT/felt. On the other hand, the crystallite size (La) of micrometric felt and CNT/felt with and without V2O5.nH2O nanostructures are calculated, demonstrating that the adherence of V2O5.nH2O Ns is better on CNT coated felt than bare felt surface, which improved the crystalline properties of nanocarbons as well.

Study of the interaction of the lactase enzyme immobilized in a carbon nanotube matrix for the development of the chemically modified carbon paste electrode

The innovative aspect of nanoparticles takes on an important role in the advancement of research on nanostructured materials. The objective of the present study was to carry out an investigation of the interactions between lactase enzyme and carbon nanotubes applied to the elaboration of a chemically modified carbon paste electrode. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), fluorescence spectroscopy, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric (TG/DTG) were conducted to comprehend the interactions and the efficiency of the enzyme immobilization in carbon nanotubes. Through studying the morphology of the materials using SEM and TEM, it was shown that there was adsorption of the lactase enzyme into the tubular area of the carbon nanotubes. Through fluorescence spectroscopy analysis, it was observed that the emission of lactase fluorescence is mainly due to tryptophan residue (Trp), and this fluorescence was reduced in the presence of CNT, demonstrating the interaction between these components. In the remaining analyses, FTIR, XRD and TG/DTG, adsorption of the lactase enzyme into the carbon nanotube matrix was demonstrated.

Phosphorus-doped carbon/carbon nanotube hybrids as high-performance electrodes for supercapacitors

P-doped carbon hybrids were prepared by hydrothermal carbonization of glucose in the presence of CNT followed by chemical activation with phosphoric acid. The role played by phosphoric acid on the final textural and chemical properties of the samples was thoroughly investigated by varying the temperature of activation. Temperatures higher than 700°C were needed to chemically activate the samples, while 800°C is the optimum temperature to generate the largest amount of micropores. In addition to oxygen functional groups such as carboxylic acids, anhydrides, lactones, phenols and carbonyl quinones, several phosphorus functional groups are also detected. At 700°C, only COPO3 and CPO3 groups are observed; meanwhile, C3P=O and C3P groups appear at 800 °C and 900 °C, respectively. The oxygen moieties bonded to carbon and the phosphates (COPO3) contribute significantly to the pseudocapacitance; the oxygen groups linked to phosphorus (CPO3 and C3P=O) enhance the electrostatic charge and the non-oxygen functional group (C3P) increases the capacitance retention. The P-doped hybrid treated at 800 °C resulted in a porous carbon material with 806 m2 g−1 active surface area and high phosphorus content (6.6%) that increases the total capacitance from 26 (non-doped hybrid treated at 700°C) to 124 F g−1 at 1 A g−1. Besides, its high content of phosphorus increases the rate capability (115 F g−1 at 10 A g−1), resulting in an electrode material with higher performance at large current density than that of commercial activated carbon Supra50.

Quantification of MWCNTs incorporated into PBTh matrix composite obtained by electrochemical polymerization and their effect on the conductive properties and structure

This paper describes the use of elemental combustion analysis for the simple quantification of multiwalled carbon nanotubes (MWCNT’s) inside a composite of polybithiophene (PBTh) matrix obtained by electrochemical polymerization. The obtained percentage in weight of MWCNT’s inside PBTh composites prepared was found between 15 % and 32 % depending on the different electropolymerization scan rates and CNTs proportion present at the polymerization solution. PBTh and PBTh/MWCNT composite properties were evaluated by in-situ electrochemical conductance method. The presence of the MWCNT’s causes a decrease in the hysteresis value (ΔEG ≈ 100 mV), and a faster charge exchange mainly in the charged-discharged transition, improving the conducting and electron transfer properties. Atomic force microscopy (AFM) scanning electronic microscopy (SEM) and X-ray diffraction (XRD) analysis let to distinguish unambiguously the presence of CNT’s and in the composite a nano fibrous structure was observed, which may explain the improvement of the electrochemical properties.

Polyacrylic acid assisted synthesis of free-standing MnO2/CNTs cathode for Zinc-ion batteries

Rechargeable aqueous zinc-ion batteries (ZIBs) have attracted significant attention due to the distinguishing characteristics of zinc metal, including its low price, abundance in earth, safety and high theoretical specific capacity of 820 mAh g−1. Manganese dioxide (MnO2) is a promising cathode for ZIBs due to high theoretical specific capacity, high discharge voltage plateau, cost-effectiveness and nontoxicity. However, the low electronic conductivity and volumetric changes during electrochemical cycling hinder its practical utilization. Herein, we demonstrate a polyacrylic acid (PAA)-assisted assembling strategy to fabricate freestanding and flexible MnO2/carbon nanotube/PAA (MnO2/CNT/PAA) cathodes for ZIBs. PAA plays an important role in providing excellent mechanical properties to the free-standing electrode. Moreover, the presence of CNT forms an electron conductive network, and the porous structure of MnO2/CNT/PAA electrode accommodates the volumetric variations of MnO2 during charge/discharge cycling. The as-fabricated quasi-solid-state Zn-MnO2/CNT/PAA battery delivers a high charge storage capacity of 302 mAh g−1 at 0.3 A g−1 and retains 82% of the initial capacity after 1000 charge/discharge cycles at 1.5 A g−1. The calculated volumetric energy density of Zn-MnO2/CNT/PAA battery is 8.5 mW h cm−3 (with a thickness of 0.08 cm), which is significantly higher than the reported alkali-ion batteries (1.3 mW h cm−3) and comparable to supercapacitors (6.8 mW h cm−3) and Ni–Zn batteries (7.76 mW h cm−3). The current work demonstrates that free-standing MnO2/CNT/PAA composite is a promising cathode for ZIBs.

Molecular dynamics simulation study of the effect of single-walled carbon nanotube on the enantioseparation ability of a chiral ionic liquid

A non-halogenated type of chiral ionic liquids (CIL's) called 1-butyl-3-methylimidazolium (T-4)-bis[(αS)-α-(hydroxy-O) benzeneacetato-κO] borate, [BMIm+] [BSMB−], has been used for enantioseparation of propranolol enantiomers. Experimental studies indicate that carbon nanotubes (CNT's) increase the Enantioselectivity of chiral ionic liquids through the enhancement of the interaction surface of chiral selectors with the compounds enantiomers. With the aim of investigating the mechanism under this observation, we used Molecular Dynamics (MD) Simulations to investigate the molecular level picture of the behavior of CIL and propranolol enantiomers on the Single-Walled Carbon Nanotube (SWCNT) surface. The density profiles, micro structure, radial distribution function, dimer existence autocorrelation function (DAF) and dynamic properties of propranolol enantiomers were studied in the CIL/CNT solution. The results are indicative of stronger interactions between R-propranolol enantiomers with CIL and CNT surface. Furthermore stronger interactions were seen between the R-propranolol molecules with one another. This leads to the difference in the replacement of propranolol enantiomers on the CNT surface in such a way that R-propranolol molecules propagate more along the CNT to have the maximum interactions with CIL molecules. The diffusion coefficient difference between S-propranolol and R-propranolol molecules shows a higher value in comparison to the system that CNT is absent. Consequently, the interactions, propagation and mobility of propranolol enantiomers are strongly influenced by CNT presence.

Electrochemical functionalization of single wall carbon nanotubes with phosphorus and nitrogen species

Single Wall Carbon Nanotubes (SWCNTs) have been successfully functionalized by electrochemical oxidation in presence of 4-aminophenyl phosphonic acid (4-APPA). Electrochemical modification has been performed by cyclic voltammetry using different upper potential limits, producing the incorporation of N and P functionalities on SWCNT through polymerization reactions, although some covalent attachment cannot be discarded. Electrochemical oxidation in presence of CNT produces polymerization of 4-APPA, what has been related to the interaction between monomer and the CNT surface. The voltammograms of the functionalized SWCNT show different well-defined redox processes that are maintained at high pH. Raman spectroscopy shows that the structure of the SWCNT is maintained even at high potentials suggesting that oxidation selectively occurs in the 4-APPA monomer favoring polymer chain growth. The degree of modification of SWCNT can be easily controlled by selecting the electrochemical conditions.

The Influence of Soft-Epitaxial Crystallization on Polyamide 66/Carbon Nanotubes Composite Injection Bar

The hydrogen–bonding-rich semi-crystalline polyamide 66 (PA66) was chosen to investigate the influence of soft-epitaxial effect on polymer/carbon nanotube (CNT) nanocomposite injection-molding bars, and the crystallization behavior was explored by differential scanning calorimeter (DSC), scanning electron microscope (SEM), two-dimensional wide angle X-ray diffraction (2D-WAXD) and two-dimensional small angle X-ray scattering (2D-SAXS). The results indicated that CNT is an effective nucleation agent for PA66 crystallization and the coupling of the flow and CNT can induce the soft-epitaxial crystallization of PA66 upon CNT surface, resulting in the coexistence of soft-epitaxial nanohybrid shish-kebab crystalline structure and conventional non-epitaxial crystals in PA66/CNT nanocomposites. Although the presence of CNT did not change the crystal structure of PA66, the generation and presence of soft-epitaxial crystals could feebly enhance the orientation degree of PA66 crystals and slightly improve the mechanical properties of PA66/CNT nanocomposites.