Surface Modification Of Carbon Nanotubes Research Articles

A Flexible Supercapacitor Prepared with Surface Modified Carbon Nanotube Film Electrode and Hydrogel Electrolyte

A Flexible Supercapacitor Prepared with Surface Modified Carbon Nanotube Film Electrode and Hydrogel Electrolyte

Effects of carbon nanotubes functionalization on mechanical and tribological properties of nitrile rubber nanocomposites: Molecular dynamics simulations

In this research, the effects of the functional group type, degree of sidewall functionalization, and different amido-amines modification of carbon nanotubes (CNTs) on the mechanical and tribological properties of nitrile rubber (NBR)/CNT nanocomposites were comprehensively studied using molecular dynamics (MD) simulations. The Young’s modulus, shear modulus, and bulk modulus of the nanocomposites were estimated by the constant strain method. Three-layer friction models were established to study the coefficient of friction and abrasion rate of CNT/NBR composites under a normal loading. It is found that among these different surface-modified CNTs (i.e., carboxyl, hydrazide, and ethylenediamine), the amide-functionalized CNT behaves the best reinforcing efficiency on the mechanical and tribological capacities of NBR nanocomposites due to the formation of strong dipole–dipole interactions, hydrogen bonding interactions, van der Waals (vdW) interactions, and good interfacial compatibility between CNTs and NBR matrices. Comparing the results obtained with different degree of sidewall functionalization, the vdW force between the amide-functionalized CNT and the NBR matrix plays a major role in determining the interfacial bonding strength. Meanwhile, higher degree of sidewall functionalization (>10%) will lower the enhancement effect by destroying the perfect structure of CNTs. Finally, the reinforcement mechanisms for the interfacial interactions between the functionalized CNTs and NBR matrices were elucidated from an atomic perspective.

Surface Modification of Carbon Nanotubes Using Carboxymethyl Cellulose for Enhanced Stress Sensing in Smart Cementitious Composites

Carbon nanotubes (CNTs) when used as additives in cementitious materials are known to enable the piezo-responses making them smart materials. The piezo-responses can potentially be used to monitor the applied forces, stress, and the resulting performances of the associated materials. An effective and reproducible method for smart cementitious material production needs to ensure uniform dispersion of CNTs within the cementitious base, and that should lead to better sensitivity and consistency in sensing by the smart cementitious materials. This paper presents a surface modification method of CNTs using carboxymethyl cellulose (CMC) to improve the performance of the CNT-modified smart cementitious materials for stress sensing. Compared to the two commonly used CNTs dispersion methods, the direct mixing and the surfactant surface treatment methods of dispersing CNTs, the new CMC surface modification method developed within this study significantly increased the stress detection sensitivity and consistency, and reduced the measurement hysteresis.

Using Wet Electrospun PCL/Gelatin/CNT Yarns to Fabricate Textile-Based Scaffolds for Vascular Tissue Engineering.

Incorporating conductive materials in scaffolds has shown advantages in regulating adhesion, mitigation, and proliferation of electroactive cells for tissue engineering applications. Among various conductive materials, carbon nanotubes (CNTs) have shown great promises in tissue engineering because of their good mechanical properties. However, the broad application of CNTs in tissue engineering is limited by current methods to incorporate CNTs in polymers that require miscible solvents to dissolve CNTs and polymers or CNT surface modification. These methods either limit polymer selections or adversely affect the properties of polymer/CNT composites. Here, we report a novel method to fabricate polymer/CNT composite yarns by electrospinning polycaprolactone/gelatin into a bath of CNT dispersion and extracting electrospun fibers out of the bath. The concentration of CNTs in the bath affects the thermal and mechanical properties and the yarns' degradation behavior. In vitro biological test results show that within a limited range of CNT concentrations in the bath, the yarns exhibit good biocompatibility and the ability to guide cell elongation and alignment. We also report the design and fabrication of a vascular scaffold by knitting the yarns into a textile fabric and combining the textile fabric with gelatin. The scaffold has similar mechanical properties to native vessels and supports cell proliferation. This work demonstrates that the wet electrospun polymer/CNT yarns are good candidates for constructing vascular scaffolds and provides a novel method to incorporate CNTs or other functional materials into biopolymers for tissue engineering applications.

Latex-Based Polystyrene Nanocomposites with Non-Covalently Modified Carbon Nanotubes.

We prepared electrically conductive polystyrene (PS) nanocomposites by incorporating non-covalently surface-modified carbon nanotubes (CNTs) with hydrophilic polymers such as polydopamine (PDA) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). Further, ethylene glycol (EG) was introduced as a second dopant to improve the electrical properties of the nanocomposites prepared with PEDOT:PSS-wrapped CNTs. All conductive PS nanocomposites were prepared through latex-based process, and the morphology and properties of the nanocomposites were investigated. The electrical properties of the nanocomposites with PEDOT:PSS-wrapped CNTs were better than those of the nanocomposites with PDA-coated CNTs owing to the conducting nature of PEDOT:PSS, although the dispersions of both types of modified CNTs in the PS matrix were excellent, as evidenced by morphology and rheology. In the case of PEDOT:PSS modification, the electrical properties of the nanocomposites with EG-doped PEDOT:PSS-wrapped CNTs were superior to those of the nanocomposites without EG treatment.

Characterization and comparison of fluoroelastomer unfilled, filled with carbon nanotube (unmodified, acid or base surface modified) and carbon black using TGA-GCMS

Carbon nanotube (CNT)-, surface-modified CNT: acid (–COOH) modified (MCNT) or base (–OH) modified (OHCNT), carbon black (CB)-filled fluoroelastomer (FE) and unfilled FE were prepared (CNT/FE, MCNT/FE, OHCNT/FE, CB/FE and FE). The thermal properties of the composites were assessed by TGA-GCMS and TGA and compared for all samples. TGA-GCMS results show that degradation products that obtained due to breakage of the CF2-CH2bond (group A) and CF2-CF2bond (group B) in base FE, obtained in lower temperatures and higher temperatures of TGA scan respectively, therefore CF2-CF2bond is more thermally stable than CF2-CH2. For degradation products of group A and group B, the relative abundance decreased in the following orders respectively for all samples: CB/FE, CNT/FE, OHCNT/FE, FE, MCNT/FE; and MCNT/FE, OHCNT/FE, FE, CNT/FE, CB/FE. Therefore nanofillers and particularly surface-modified nanofillers produce less amount of group A degradation products and more amount of group B degradation products and therefore increase the thermal stability of the base FE. For all samples, the volatile degradation products that have the highest intensity are: (C6F7H2)•+, C4H6F+and C6F11+and the volatile degradation products are similar except for OHCNT/FE and MCNT/FE. TGA results also show that thermal stability reduced in the following orders in the lower temperature range and higher temperature range respectively: OHCNT/FE, FE, CB/FE, CNT/FE, MCNT/FE; and CB/FE, MCNT/FE, CNT/FE, FE, OHCNT/FE. Totally the results show that OHCNT/FE, MCNT/FE and CNT/FE can be used at high temperatures for making O-rings for very deep oil and gas drilling.

Surface functionalization of CNTs by a nitro group as a sensor device element: theoretical research

The problem of modifying carbon nanotubes (CNTs) by functional groups is relevant in connection with the intensive development of the nanoindustry, in particular, nano- and microelectronics. For example, a modified nanotube can be used as a sensor device element for detecting microenvironments of various substances, in particular, metals included in salts and alkalis. The paper discusses the possibility of creating a highly efficient sensor using single-walled carbon nanotubes as a sensitive element, the surface of which is modified with the functional nitro group —NO2. Quantum-chemical research of the process of attaching a nitro group to the outer surface of a single-walled CNTs of the (6, 0) type were carried out, which proved the possibility of modifying CNTs and the formation of a bond between the —NO2 group and the carbon atom of the nanotube surface. The results of computer simulation of the interaction process of a surface-modified carbon nanotube with alkali metal atoms (lithium, sodium, potassium) are presented. The sensory interaction of a modified carbon nanosystem with selected metal atoms was investigated, which proved the possibility of identifying these atoms using a nanotubular system that can act as a sensor device element. When interacting with alkali metal atoms in the “СNT – NO2” complex, the number of major carriers increases due to the transfer of electron density from metal atoms to the modified CNTs. The results presented in this paper were obtained using the molecular cluster model and the DFT calculation method with the exchange-correlation functional B3LYP (valence split basis set 6-31G).

A single step in-situ process for improvement in electron emission properties of surface-modified carbon nanotubes (CNTs): Titanium dioxide nanoparticles attachment

Carbon nanotubes (CNTs) are excellent material for electron emission-based cold cathode devices application because of high aspect ratios, low turn-on and threshold field. In this present work, we have synthesized the as functionalized CNTs with TiO2 NPs (nanoparticles) for enhancing the electron field emission by single-step growth. The attachment of TiO2 NPs is a single step in-situ process. FESEM micrograph indicates the surface alteration/modification by attaching the TiO2 NPs. These nanoparticles enhanced the edge effect and reducing the screen effect. TEM micrograph reveals the uniform distribution of TiO2 NPs over the surface. The Raman spectra strongly indicate the active peaks of anatase TiO2 along with the D and G band of the CNTs and their intensity ratio (IG/ID) for pristine – CNTs and CNTs–TiO2 NPs which confirms it graphitic nature. Due to the attachment of TiO2 NPs to CNTs peaks shifting towards the higher frequency, reduced the work function to 2 eV, and enhanced the edge effect which means electron field emission site density increased and hence, reducing the screening effect. Electron emission analysis of CNTs–TiO2 NPs in contrast with pristine – CNTs showed a better low turn-on electric field (Eto) with the threshold field (Eth). The value of conventional characteristics field enhancement factor γ for CNTs–TiO2 NPs enhanced in comparison to pristine – CNTs. Excellent electron emission stability was also observed by both pristine – CNTs and CNTs–TiO2 NPs. In both samples, emission current becomes stable after 250 min. CNTs–TiO2 NPs had shown higher electron emission stability. CNTs–TiO2 NPs can be highly useful for electron emission-based vacuum device applications.

Prediction of tensile strength of polymer carbon nanotube composites using practical machine learning method

This paper is devoted to the development and construction of a practical Machine Learning (ML)-based model for the prediction of tensile strength of polymer carbon nanotube (CNTs) composites. To this end, a database was compiled from the available literature, composed of 11 input variables. The input variables for predicting tensile strength of nanocomposites were selected for the following main reasons: (i) type of polymer matrix, (ii) mechanical properties of polymer matrix, (iii) physical characteristics of CNTs, (iv) mechanical properties of CNTs and (v) incorporation parameters such as CNT weight fraction, CNT surface modification method and processing method. As the problem of prediction is highly dimensional (with 11 dimensions), the Gaussian Process Regression (GPR) model was selected and optimized by means of a parametric study. The correlation coefficient (R), Willmott’s index of agreement (IA), slope of regression, Mean Absolute Percentage Error (MAPE), Root Mean Squared Error (RMSE) and Mean Absolute Error (MAE) were employed as error measurement criteria when training the GPR model. The GPR model exhibited good performance for both training and testing parts (RMSE = 5.982 and 5.327 MPa, MAE = 3.447 and 3.539 MPa, respectively). In addition, uncertainty analysis was also applied to estimate the prediction confidence intervals. Finally, the prediction capability of the GPR model with different ranges of values of input variables was investigated and discussed. For practical application, a Graphical User Interface (GUI) was developed in Matlab for predicting the tensile strength of nanocomposites.

Poly(diallyldimethylammonium chloride)-grafted carboxylated-MWCNT as an additive in the polyethersulfone membrane

Surface modification of carbon nanotubes is a common method to improve their compatibility with polymer matrix in membranes. In this study, polyethersulfone (PES) nanocomposite membranes were prepared by incorporation of modified multi-walled carbon nanotubes (MWCNT). For this purpose, diallyldimethylammonium chloride was used as a monomer for the functionalization of carboxylated-MWCNT via in situ polymerization. Synthesized polymer possessed a positive charge on repeating unit, which increased the hydrophilicity of carboxylated-MWCNT. The properties and performances of the modified carboxylated-MWCNT and nanocomposite membranes were investigated by field emission scanning electron microscopy, thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FT-IR), contact angle measurement, salt, heavy metal, and dye removal, and fouling studies. The occurrence of the modification reaction was confirmed by FT-IR and TGA studies. Results showed that the incorporation of modified carboxylated-MWCNT into polyethersulfone membranes improved their performance in the separation of salts, heavy metal ions, and dyes. Furthermore, the surface hydrophilicity of membranes was improved by loading of modified carboxylated-MWCNT, and other properties like the pure water flux and anti-fouling resistance of PES membranes were refined remarkably. More importantly, the membranes containing modified additive showed pH sensitivity because of ammonium groups in the attached polymer chain.

Synthesis and plasma surface functionalization of carbon nanotubes for using in advanced epoxy-based nanocomposites

In this study, thermal chemical vapor deposition (CVD) method was utilized to fabricate carbon nanotubes (CNTs) using an Fe/Al catalyst. Plasma enhanced CVD (PECVD) was applied to coat CNTs surfaces with a hydrophobic poly(hexafluorobutyl acrylate) (PHFBA) thin film. Then pure CNT and surface-modified CNT (f-CNT) were used as nanofillers at 0.5–3 wt% in bisphenol-A (DGEBA) and phenolic novolac types epoxy (EPN) resins to produce composite materials with superior properties. For characterization of both types of CNTs, FTIR, XRD, SEM, TEM and TGA analyses were performed. The morphologies of composites were examined via XRD and SEM. Thermal properties of composites were revealed by TGA. The influences of CNT surface functionalization and matrix type on the thermal, mechanical, electrical conductivity and surface wettability properties of composites were investigated. EPN based composites exhibited higher mechanical properties than that DGEBA based ones. At 1.5 wt% f-CNTs, the Young's modulus and tensile strength of the nanocomposites were found 6.9 ± 0.50 GPa and 141.0 ± 7.8 MPa, respectively using DGEBA matrix; 8.7 ± 0.59 GPa and 153.4 ± 7.9 MPa respectively, using EPN matrix. Composites electrical conductivity increased with increasing both type CNTs amount and reached a maximum value of 10−4 S/m and 10−6 S/m at 3 wt% of neat and f-CNTs contents.

The Molecular and Macromolecular Level of Carbon Nanotube Modification Via Diazonium Chemistry: Emphasis on the 2010s Years

The present review focusses on the recent progress in the reductive grafting of diazotized big molecules and polymers on carbon nanotubes (CNTs). We briefly summarize the essentials on diazonium synthesis and discuss the CNT physical properties. The different routes for CNT covalent functionalization through diazonium salt interface chemistry are reviewed. The main analytical and spectroscopic techniques used to track carbon nanotube surface modification were cited as well as their advantages and limitations in the light of the information they provide. In this review, the emphasis is on big molecules such as dyes, crown ether, calixarene, cyclodextrin, fullerene and Ru-complex, and biomolecules such as biotin, proteins, and antibodies. The attachment of synthetic polymers to CNT via diazonium chemistry, or by preparing CNT-Polymer nanocomposites through: (1) in situ polymerization (controlled radical polymerization and click chemistry). (2) Oxidative polymerization of conjugated monomers. (3) Grafting onto method by Huisgen 1,3-cycloaddition click reaction and epoxy ring-opening were summarized and discussed. Throughout this review, we reported the recent advances using diazonium salt chemistry in numerous research areas (biomedicine, environment, energy conversion, sensors and actuators, structural composites,…).

Plasma Treatment As an Effective Way of Modifying Carbon-Based Electrocatalysts for an Enhanced Oxygen Reduction Reaction

Oxygen reduction reaction (ORR) is pivotal in renewable energy technologies such as in fuel cells and metal-air batteries. Precious metal-free electrochemical ORR is a critical component in designing cost-effective electrochemical energy conversion devices. In this report we demonstrate an efficient surface modification of carbon nanotubes (CNT) through one-step oxygen plasma irradiation that induces doping and charge redistribution around the doped heteroatom oxygen that promotes ORR activity. The defect sites generated owing to oxygen dopant in CNTs were confirmed by Raman spectra, X-ray photoelectron spectroscopy (XPS) surface composition and CHNO elemental analysis. The O-doped CNTs were thoroughly characterized by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) measurements. Our research shows that plasma-treated single-walled carbon nanotubes (SWCNT) are more effective ORR catalyst compared to multi-walled carbon nanotubes (MWCNT) due to the inherent structure of SWCNT that can access more defects and surface functional groups than MWCNT.In the following study, plasma modification approach was implemented in the synthesis of a highly active robust Metal-Nitrogen-Carbon (M-N-C) catalysts through NH3-plasma pretreatment on high surface area black pearl carbon. Pre-treated FeNC/NH3-C contains Fe3C and Fe-Nx as catalytically active sites. XPS confirms the presence of a high surface concentration of pyrrolic to pyridinic nitrogen and ferrous sites on FeNC/NH3-C that promotes low oxygen reduction overpotential (0.80 V vs RHE in 0.5 M H2SO4 and 0.96 V vs RHE in 0.1 M KOH). Hence plasma activates the surface and incorporates nitrogen which forms stable Fe-N coordination for accelerating oxygen reduction. Importantly, FeNC/NH3-C shows lower peroxide yield at 0.6V/RHE (<20% in 0.5 M H2SO4 and <2 % in 0.1 M KOH) that can reduce the detrimental effect of H2O2 on the catalysts support and exhibits high stability, seen from thousands of potential cycling stability tests of FeNC/NH3-C in acid solutions. Thereby this plasma-based new synthetic approach can promote more active and stable non-precious metal catalysts.

Surface modification of carbon nanotube with gelatin via mussel inspired method.

Carbon nanotube (CNT) has aroused much attention in biomedical field. However, the cytotoxicity and aggregation are critical factors that affect the application of carbon nanotube (CNT). Herein, gelatin was grafted on the surface of CNT via mussel-inspired method. The gelatin modified CNT can disperse homogeneously in water. The in vitro test showed that gelatin modified CNT showed much better biocompatibility than the native CNT, which may improve its potential application in biomedical field.

In situ nitrogen-doped, defect-induced carbon nanotubes as an efficient anode for sodium-ion batteries

The incorporation of heteroatoms and defects in carbonaceous material is a well-known approach to improve the electrochemical performance of the anode in a sodium-ion battery (NIB). However, previous works aimed to use either heteroatom-doped or defect-enriched carbon material. The present work focuses on nitrogen-doped, defect-induced surface-modified carbon nanotubes (MN-BCNT) having the synergy of both the effects to improve the electrochemical performance of the NIB. Initially, in situ nitrogen-doped CNTs were grown using a scalable, cost-effective and green synthesis technique. In situ nitrogen doping introduces lattice defects resulting in bamboo-shaped CNTs. The defects were further enriched by opening the ends of the tubes and also by shortening them. This structure demonstrates the high capacity of 278 mA h g−1 at a current density of 50 mA g−1, which is more than double compared to conventional CNTs. The improved performance of MN-BCNT is attributed to the improved electrical conductivity due to nitrogen doping and the availability of significant active sites as a result of tube shortening. Moreover, the designed structure shows good cyclic stability at 200 mA g−1 accompanied with excellent rate capability.

Different Approaches to Oxygen Functionalization of Multi-Walled Carbon Nanotubes and Their Effect on Mechanical and Thermal Properties of Polyamide 12 Based Composites

In this work the preparation of polyamide 12 (PA12) based composites reinforced with pristine and surface-modified carbon nanotubes is reported. A qualitative and quantitative evaluation of multi-walled carbon nanotube functionalization with oxygen containing reactive groups achieved by different procedures of chemical treatment is presented. Simple strong oxidative acid treatment as well as chlorination with subsequent chloroacetic acid treatment were applied. Carbon nanotubes (CNTs) were also subjected to chlorine and ammonia in gaseous atmosphere with small differences in after-ammonia treatment. Commercial COOH-functionalized carbon nanotubes were compared with nanotubes that were laboratory modified. The effect of CNT functionalization was evaluated basing on the improvement of mechanical and thermal properties of polyamide 12 composites prepared by in situ polymerization. It was found that high concentration of oxygen-containing functional groups on nanotube surface is not sufficient to improve the composite performance if the structure of carbon nanotubes is defective. Indeed, the best effects were achieved for composites containing nanotubes modified under mild conditions, seemingly due to a compromise between morphology and surface chemical structure.

Surface modification of carbon nanotubes with polyethyleneimine through “mussel inspired chemistry” and “Mannich reaction” for adsorptive removal of copper ions from aqueous solution

A number of nanomaterials, such as silicon dioxide, graphene oxide, nano-diamond, etc. have been discovered and reported for various applications in recent years. The removal of environmental pollutants using nanomaterials should be one of the most important topics owing to their small size, high specific surface areas and catalytical properties. However, the removal capability of some nanomaterials is still need to improve for the lack of active adsorption sites. The surface modification of nanomaterials to endow new functional groups should be promising route to improve their adsorption performance. In this work, a novel strategy that combination of mussel inspired chemistry and Mannich reaction was reported for the first time for preparation of CNT@PDA@PEI composites. The adsorption behaviors of the modified carbon nanotubes (CNT) and pristine CNT toward Cu2+ have been determined and compared to verify the effects of surface modification. The CNT related samples were characterized by a series of instruments. The results further indicated that the method is an excellent route of surface modification of CNT. The adsorption experimental results suggested that the functionalized CNT via the combination of Mannich reaction and mussel inspired chemistry was an excellent adsorbent for removal of Cu2+. To the best of our knowledge, this is the first report for surface modification of CNT through the combination of mussel inspired chemistry and Mannich reaction. This method could also be expanded for the surface modification of other materials for various applications owing to the universality of mussel inspired chemistry and well designability of multicomponent reactions.

Utilization of carbon nanotubes in removal of heavy metals from wastewater: a review of the CNTs’ potential and current challenges

Carbon nanotubes-based adsorbents have attracted substantial interest as potential adsorbents for heavy metals removal. However many aspects such as the interaction between the modified carbon nanotubes (CNTs) and the heavy metal ions, quantitative effect of the functional groups and regeneration of CNTs-based adsorbents are not fully understood yet. A critical review was performed to compile an extensive profile from several studies of using pristine and modified CNTs for heavy metals removal. CNTs demonstrated a great potential. However surface modification of CNTs is necessary as pristine CNTs may be ineffective in arsenite [As (III)] or arsenate [As (V)] removal. Isotherms and kinetic models for the removal of heavy metals are discussed in details. A particular focus has been placed on better understanding the mechanism of heavy metals removal using CNTs-based adsorbents, affecting factors, maximum adsorption capacity and regeneration. The effect of adsorbent dose, pH, initial concentration, and contact time were addressed by several researchers, which specifies the consistency and performance of CNTs-based materials as potential adsorbents. To elucidate the mechanism of adsorption, FT-IR, XPS, SEM, TEM and EDX results have been reviewed and discussed. It is found that Langmuir, Freundlich and second order kinetic models are the most frequently used isotherm to describe heavy metals adsorption. CNTs-based adsorbent can be efficiently regenerated.

The combination of Diels-Alder reaction and redox polymerization for preparation of functionalized CNTs for intracellular controlled drug delivery.

Carbon nanotubes (CNTs) are a novel type of one-dimensional carbon nanomaterials that have been widely utilized for biomedical applications such as drug delivery, cancer photothermal treatment owing to their high surface area and unique interaction with cell membranes. However, their biomedical applications are still impeded by some drawbacks, including poor water dispersibility, lack of functional groups and toxicity. Therefore, surface modification of CNTs to overcome these issues should be importance and of great interest. In this work, we reported for the first time that CNTs could be surface modification through the combination of Diels-Alder (D-A) reaction and redox polymerization, this strategy shows the advantages of mild reaction conditions, water tolerance, low temperature and hydroxyl-surfaced initiator. In this modification procedure, the hydroxyl groups were introduced on the surface of CNTs through the D-A reaction that was adopted for grafting the copolymers, which were initiated by the Ce(IV)/HNO3 redox system using the hydrophilic and biocompatible poly(ethylene glycol) methyl ether methacrylate (PEGMA) and carboxyl-rich acrylic acid (AA) as monomers. The final CNTs-OH-PAA@PEGMA composites were characterized by a series of characterization techniques. The drug loading and release results suggested that anticancer agent cis‑platinum (CDDP) could be loaded on CNTs-OH-PAA@PEGMA composites through coordination with carboxyl groups and drug release behavior could be controlled by pH. More importantly, the cell viability results clearly demonstrated that CNTs-OH-PAA@PEGMA composites displayed low toxicity and the drug could be transported in cells and still maintain their therapeutic effects.

Surface modification of carbon nanotubes for the synthesis of CNTs/ZnS quantum dot composites via electrophoretic deposition route

In the present study, carbon nanotube (CNT)/zinc sulfide (ZnS) quantum dots (QDs) were synthesized followed by electrophoretic deposition on Al electrodes. First, surface of carbon nanotubes were modified using wet chemical routes to obtain Carboxyl-, Chlorine- and Amine-modified CNTs. Then, ZnS QDs were synthesized by hydrothermal method and attached to the CNTs. Although deposition weight of CNTs were improved considerably by surface modification, it decreased dramatically after attachment of ZnS QDs. Microstructure studies showed that a better coverage has been obtained on the Al substrate by the continuous layer of Carboxyl-modified CNTs. Moreover, ZnS QDs were coated on the surface of Carboxyl-modified CNTs properly.