Structure Of Multi-walled Carbon Nanotubes Research Articles

High-Performance Ionanofluids from Subzipped Carbon Nanotube Networks

Investments in the transfer and storage of thermal energy along with renewable energy sources strengthen health and economic infrastructure. These factors intensify energy diversification and the more rapid post-COVID recovery of economies. Ionanofluids (INFs) composed of long multiwalled carbon nanotubes (MWCNTs) rich in sp2-hybridized atoms and ionic liquids (ILs) display excellent thermal conductivity enhancement with respect to the pure IL, high thermal stability, and attractive rheology. However, the influence of the morphology, physicochemistry of nanoparticles and the IL-nanostructure interactions on the mechanism of heat transfer and rheological properties of INFs remain unidentified. Here, we show that intertube nanolayer coalescence, supported by 1D geometry assembly, leads to the subzipping of MWCNT bundles and formation of thermal bridges toward 3D networks in the whole INF volume. We identified stable networks of straight and bent MWCNTs separated by a layer of ions at the junctions. We found that the interactions between the ultrasonication-induced breaking nanotubes and the cations were covalent in nature. Furthermore, we found that the ionic layer imposed by close MWCNT surfaces favored enrichment of the cis conformer of the bis(trifluoromethylsulfonyl)imide anion. Our results demonstrate how the molecular perfection of the MWCNT structure with its supramolecular arrangement affects the extraordinary thermal conductivity enhancement of INFs. Thus, we gave the realistic description of the interactions at the IL-CNT interface with its (super)structure and chemistry as well as the molecular structure of the continuous phase. We anticipate our results to be a starting point for more complex studies on the supramolecular zipping mechanism. For example, ionically functionalized MWCNTs toward polyionic systems─of projected and controlled nanolayers─could enable the design of even more efficient heat-transfer fluids and miniaturization of flexible electronics.

Influence of multi-walled carbon nanotubes in polytetrafluoroethylene on the parameters of electronic structure and absorption of ultra-high-frequency radiation

Using the methods of angular correlation of annihilation radiation (ACAR), attenuation of electromagnetic radiation in 1.5–2.2 GHz frequency range, and optical ellipsometry, it was shown that in composites of polytetrafluoroethylene (PTFE) + multi-walled carbon nanotubes (MWCNTs), a 2% decrease in the probability of annihilation of positrons in free volumes in PTFE leads to changes in other parameters of electronic structure of composites by 8–29%. Polytetrafluoroethylene is transparent to electromagnetic radiation, but after the addition of 10 wt.% or more of MWCNTs, the composites demonstrate 200–410-fold decrease in the electromagnetic radiation intensity when the radiation passes through a specimen with a thickness of ≈2 mm. It was found that the average radius of the free volumes and the probability of annihilation of positrons are determined by the defect and electronic structures of the polymer matrix only. The Fermi angle and the probability of positrons annihilation with free electrons are determined by the analogous structures of MWCNTs only. Since the electronic characteristics of the atoms and defects in the polymer matrix (at least outside the interphase) do not change, the changes in the other ACAR parameters are mainly due to changes in the imperfect MWCNTs’ atomic and electronic structures. The average radius of free volumes reaches its maximum value in the composite with 10 wt.% MWCNTs. It was found that in a specimen with 10 wt.% MWCNTs, the highest density of free electrons is observed due to charge transfer from free volumes to MWCNTs, and the highest electron density is observed on defects. A disorder of MWCNTs and their branched conductive network can form the ‘tails’ of electronic density of states in a band gap. Thus, composite with 10 wt.% MWCNTs has the highest absorption coefficient for electromagnetic radiation.

Surface Modification of Carbon Fiber for Enhancing the Mechanical Strength of Composites.

The surface of carbon fibers (CFs) is often modified by multi-walled carbon nanotubes (MWCNTs), and the effect of the interface on the mechanical properties has been reported mostly for epoxy matrices. We achieved effective surface modification of CFs by a simple two-step process to graft a large amount of MWCNTs using a highly reactive polymer to enhance the bonding between CFs and MWCNTs. The first step was the reactive mono-molecular coating of a reactive polymer (poly-2-isopropenyl-2-oxazoline; Pipozo) that has high reactivity with COOH from CFs and MWCNTs. The high reactivity between the oxazoline group and COOH or phenol OH was confirmed for low-molecular-weight reactions. The second step was the coating of MWCNTs from a dispersion in a solvent. This simple process resulted in a substantial amount of MWCNTs strongly bonded to CF, even after washing. The MWCNTs grafted onto CFs remained even after melt-mixing. The effect on the interface, i.e., physical anchoring, led to an improvement of the mechanical properties. The novelty of the present study is that Pipozo acted as a molecular bonding layer between CFs and MWCNTs as a physical anchoring structure formed by a simple process, and the interface caused a 20% improvement in the tensile strength and modulus. This concept of a composite having a physical anchoring structure of MWCNTs on CFs has potential applications for lightweight thermoplastics, such as in the automotive industry.

Unveiling the effect of gas treatment on the electronic structure of carbon nanotube-supported Pd catalysts for electroreduction of H2O2 and Heck reaction

This study explored the impact of gas treatments on the structures of multi-walled carbon nanotubes supported Pd (CNT-Pd) catalysts used for electrocatalytic H2O2 reduction and the Heck cross-coupling reaction. The CNT-Pd catalyst was prepared by anchoring Pd nanoparticles on thiolated CNTs. XPS was conducted to examine the surface composition and electronic structure changes of the CNT-Pd catalyst before and after gas treatment. The XPS results revealed that as-prepared CNT-Pd contains at least two different oxidation states on the surface, whereon their proportions depend on the gas used for treatment. Treatment with H2 leads to Pd(0) enrichment near the surface, while O2 treatment causes Pd(Ⅱ) enrichment of CNT-Pd. All catalysts containing both Pd(0) and Pd(Ⅱ) were active toward H2O2 reduction, and the Heck cross-coupling reaction of n-butyl acrylate and 4-iodotoluene; increased proportion of metallic Pd(0) boosted the catalytic reaction. However, the catalyst stability increased as the amount of Pd(II) increased.

Effects of carbon nanotubes and sintering parameters on microstructure and properties of PCD

Polycrystalline diamond (PCD) was sintered from onion-like carbon (OLC) mixed with multi-walled carbon nanotube (MWCNT) at 5.5 GPa/1100–1300 °C/5–20 min holding time, in which OLC was generated by vacuum annealing of nano-diamond. Structures, morphologies, and properties of composites were characterized by X-ray diffraction, field emission scanning electron microscope, high-resolution transmission electron microscopy, and hardness measurement. The purposes of this paper were to lower the temperature of OLC conversion into PCD and optimize the performance of the PCD. The influence of sintering parameters on the microstructure and properties of PCD and the change of MWCNT and OLC structure in high-pressure and high-temperature (HPHT) were studied. Finally, when the mass fraction of carbon nanotubes is 10 %, the optimal process conditions were as follows: sintering pressure 5.5 GPa, temperature 1150 °C, holding time 20 min, sintering hardness was 18.84 GPa, and conversion rate of OLC to diamond was 25.96 %. Under the influence of HPHT and surrounding OLC, the MWCNT tends to be transformed into spheroids, while the structure of the OLC/MWCNT binding zone is graphite. This work not only provided a theoretical basis for the study of carbon nanotubes but also provided reasonable parameters for the synthesis of PCD.

Structure and magnetic properties of MWCNTs decorated by NiFe, CoFe, NiCo nanoparticles

The method of salt impregnation was applied to grow magnetic alloy nanoparticles (Ni20Fe80, Co93Fe07 or Ni20Co80) on multi-walled carbon nanotubes (MWCNTs). It was confirmed by SEM and XRD that the method gives nanopowders where the metal component is in the form of granules (20-40 nm in diameter) which are distributed over the surface and edges of the nanotubes. Measurements of magnetic properties confirmed that magnetic particles are small single-domain, randomly oriented assembly of spherical (or close to spherical) particles on the MWCNTs surface. Saturation magnetization of the investigated nanopowders weakly depends on temperature while coercive field increases under temperature decrease.

Analysis of structure and electrochemical characteristics of multi-walled carbon nanotubes doped with nitrogen using ion irradiation

Comparative study of the electronic structure and electrochemical characteristics of multi-walled carbon nanotubes (MWCNTs) doped with nitrogen using synthesis with a nitrogen-containing precursor (N-MWCNTs), as well as using N2+ ion irradiation with an average energy of ∼ 5 keV was provided. Using XPS, it was shown that the surface of irradiated MWCNTs contains 5.6 at.% nitrogen, which is predominantly in the pyridine and pyrrole configurations, as well as there are 12.8 at.% of oxygen in carbon–oxygen and nitrogen–oxygen chemical bonds. The N-MWCNTs surface contains 2.5 at.% nitrogen, ∼ 25% of which presents in the form of N2. An analysis of the electrochemical characteristics showed that irradiated carbon nanotubes have higher specific capacitance and rate capability. It is shown that the increase in characteristics is provided due to reversible redox processes occurring with the participation of nitrogen and oxygen groups on the surface of carbon nanotubes.

Preparation of NiO/MWCNTs nanocomposite for the removal of cadmium ions

In this work, a portable nanocomposite film made from nickel oxide nanoparticles (NiO NPs), multi-walled carbon nanotubes (MWCNTs), and polyvinyl alcohol (PVA) was prepared and investigated for the removal of Cd (II) from an aqueous solution. The preparation was carried out by eco-friendly pulsed laser ablation in liquid environmental technique to synthesize NiO NPs and to decorate MWCNTs to form NiO NPs/MWCNTs nanocomposites, followed by the formation of a portable nanocomposite film from the interaction between PVA and NiO NPs/MWCNTs nanocomposite. After that, the physicochemical properties of the prepared samples were investigated by XRD, SEM, EDX, TGA, and FT-IR. From structural analysis, the matrix nanocomposite film showed the presence of the hexagonal structure plane of NiO, PVA, and graphite, and its elemental analysis has just C, O, and Ni, which represent the constituent elements of the PVA matrix, MWCNTs, and NiO NPs. From morphological analysis, NiO NPs were loaded on the outer surface of the tubular structure of MWCNTs in a spherical shape. From optical analysis, the typical transmittance peaks of Ni–O–C and Ni–O were appeared. Also, the peaks related to the main functional groups of MWCNTs were shifted due to the interactions between MWCNTs and NiOs by non-covalent bonds. From thermal analysis, the thermal degradation is similar to that of pure PVA, but with higher percentage of decomposition due to presence of MWCNTs and NiO NPs. Furthermore, the effects of several parameters, such as pH, initial Cd (II) concentration, and adsorbent dosage, were studied in order to reach their maximum adsorption, representing the optimal conditions for the removal of Cd (II) from an aqueous solution. From these results, the adsorption of these heavy metal ions increased with pH and peaked at about pH 7–8. Also, their percentages of adsorption increased as the weight of the adsorbent dosage was raised. Based on these findings, it can be inferred that the produced nanocomposite might be an effective adsorbent for metal ions in aqueous solutions. So, these results showed the capability of using NiO NPs/MWCNTs/PVA nanocomposite film in a water treatment process and that it might be utilized to purify water before it is released into the natural environment.

Modification of Multi-Wall carbon nanotubes using controlled microwave Irradiation: Experimental determination of the enthalpy change

Irradiation of multi-wall carbon nanotubes (MWCNT) was performed at different energy densities to characterize structural changes induced by a highly localized 2.45 GHz electric field. For this purpose, a transversal electric (TE102) resonant microwave cavity was designed and coupled to a standard 800 W microwave oven magnetron. The nanotubes were sealed inside a Pyrex reactor at 10-4 Torr to avoid oxidation or reactions with the environment. Irradiated MWCNT properties were characterized using Raman Spectroscopy, Fourier Transform Infrared Spectroscopy, Thermogravimetry, Solubility tests and Transmission Electron Microscopy. In this work, the energy densities required to modify the MWCNT structure were obtained through an optical method. From an energy density of 82 J/cm3, nanotubes presented nondestructive structural changes, loss of catalytic particles and a decrease of amorphous carbon structures on the surface. A more effective modification with high purity and clearly better structured walls was observed for 167 J/cm3. Furthermore, it was determined that at an energy density of 6.9 KJ/mol a higher purification of MWCNTs is obtained. This value is in agreement with the enthalpy of formation reported for the MWCNTs. This experimental approach could be applied for the functionalization of carbon nanostructures. Finally, the purification process is easily scalable, environmentally friendly and makes maximum use of the irradiated energy.

The hybrids of perylene tetracarboxylic acid functionalized multi-walled carbon nanotubes and chitosan for electrochemical chiral sensing of tryptophan enantiomers

To introduce abundant carboxyl (COOH) groups to the surface of multi-walled carbon nanotubes (MWCNTs) while maintaining the pristine structure of MWCNTs, 3,4,9,10-perylene tetracarboxylic acid (PTCA) was non-covalently grafted to the sidewalls of MWCNTs. The obtained PTCA functionalized MWCNTs (MWCNTs–PTCA) functioned as a scaffold for the further introduction of chitosan (CS) via electrostatic attractions and hydrogen-bonds. The resultant CS/MWCNTs–PTCA could be used for electrochemical chiral sensing of tryptophan (Trp) enantiomers due to the intrinsic chirality of CS and the high electrocatalytic activity of MWCNTs. Under optimized conditions, the Trp enantiomers could be effectively discriminated at the CS/MWCNTs–PTCA modified electrode by differential pulse voltammetry (DPV), demonstrating that the developed CS/MWCNTs–PTCA might be a potential candidate for the construction of electrochemical chiral sensors.

The effect of He : O plasma treatment on the structure of multi-walled carbon nanotubes

The functionalization of multi-walled carbon nanotubes in He : O plasma is investigated. It is shown that plasma treatment leads to the removal of defective outer graphene layers and their fragments due to oxidation. It is established that the surface of functionalized multi-walled carbon nanotubes contains numerous uncoordinated carbon atoms and oxygen-containing functional groups. The preservation of the structure of the internal graphene layers of nanotubes and the formation of broken chemical bonds ensure a decrease in electrical resistance. At the same time, there is a narrowing of the distribution of electrical resistance values of nanotube ensembles. Keywords: multi-walled carbon nanotubes, plasma treating, functionalization, transmission electron microscopy, X-ray photoelectron spectroscopy

Spinel nickel cobaltite nanoflakes anchored multiwalled carbon nanotubes driven photocatalyst for highly efficient degradation of organic pollutants using natural sunlight irradiation

Natural sun light driven photocatalytic materials have received remarkable attention due to their imminent applications in environmental remediation and energy conversions. In this study, natural sun light driven hierarchal spinel nickel cobaltite nanoflakes (NiCo 2 O 4 ) anchored multiwalled carbon nanotubes (MWCNTs) nanocomposite was synthesized by using simple chemical route. The structural, morphological and functional group of as-prepared NiCo 2 O 4 anchored MWCNTs was studied by using X-ray diffractometry, field emission scanning electron microscopy and Fourier transform infrared spectroscopy. The UV–vis diffusive reflectance spectroscopy results demonstrated decrease in optical bandgap from 1.32 to 1.16eV compared with pristine spinel NiCo 2 O 4 nanoflakes. MWCNTs anchored NiCo 2 O 4 showed extremely good photocatalytic behavior and we verified 98% degradation of MB in 35 min under natural sun light. NiCo 2 O 4 anchored MWCNTs also confirmed its excellent stability and reusability by retaining 96% of photocatalytic efficiency after 7 cycles of operation. Improved photocatalytic behavior of NiCo 2 O 4 anchored MWCNTs nanocomposite in comparison to NiCo 2 O 4 nanoflakes is mainly attributed to excellent electron storage ability of MWCNTs which made catalyst a great acceptor. Moreover, porous structure of MWCNTs not only provides large surface area with more active sites but also increases conductivity and decreases agglomerations on the surface of material which render e - /h + pair recombination. Overall, this work shed new light for the synthesis of NiCo 2 O 4 anchored MWCNTs with enhanced photocatalytic properties.

Silicone Elastomer Composites Fabricated with MgO and MgO-Multi-Wall Carbon Nanotubes with Improved Thermal Conductivity.

The effect of multiwall carbon nanotubes (MWCNTs) and magnesium oxide (MgO) on the thermal conductivity of MWCNTs and MgO-reinforced silicone rubber was studied. The increment of thermal conductivity was found to be linear with respect to increased loading of MgO. In order to improve the thermal transportation of phonons 0.3 wt % and 0.5 wt % of MWCNTs were added as filler to MgO-reinforced silicone rubber. The MWCNTs were functionalized by hydrogen peroxide (H2O2) to activate organic groups onto the surface of MWCNTs. These functional groups improved the compatibility and adhesion and act as bridging agents between MWCNTs and silicone elastomer, resulting in the formation of active conductive pathways between MgO and MWCNTs in the silicone elastomer. The surface functionalization was confirmed with XRD and FTIR spectroscopy. Raman spectroscopy confirms the pristine structure of MWCNTs after oxidation with H2O2. The thermal conductivity is improved to 1 W/m·K with the addition of 20 vol% with 0.5 wt % of MWCNTs, which is an ~8-fold increment in comparison to neat elastomer. Improved thermal conductive properties of MgO-MWCNTs elastomer composite will be a potential replacement for conventional thermal interface materials.

Morphology and tensile performance of MWCNT/TiO2-epoxy nanocomposite

In this study, TiO2 nanoparticles are decorated on multi-walled carbon nanotubes (MWCNTs) by exploitation of opposite zeta potential of MWCNTs and TiO2 nanoparticles without degrading the hexagonal interatomic structure of MWCNT and generated new MWCNT/TiO2 hybrid nanofiller (MT hybrid nanofiller). The newly obtained MT hybrid nanofiller (from 0.25 wt% to 1.50 wt%) is loaded in crosslinking epoxy matrix to understand the multiphase nanocomposite in terms of mechanical performance under various stresses (storage modulus, loss modulus, tensile strength and modulus). The decoration of TiO2 nanoparticles on MWCNTs changes the fracture mechanism in the mirror zone and generates a new fracture surface, which changes the behavior of multiphase nanocomposite under various types of stresses.

Mechanism and characterization of polydopamine modified multi-walled carbon nanotubes reinforcement of natural rubber latex composites

Multi-walled carbon nanotubes (MWCNTs) are generally applied to reinforce macromolecular material due to their low density, high thermal conductivity, and high elastic modulus. However, the reinforcement effect of MWCNTs is not significant due to their poor dispersion. In this paper, we modified MWCNTs by using polydopamine (PDA). We found this is the best way to improve the dispersity of MWCNTs. We characterized the π-π conjugation reaction between MWCNTs and polydopamine by TGA, FTIR, and Raman spectroscopy. The results indicated the physical adsorption of PDA did not change the structure of MWCNTs. Besides, we also tested the mechanical properties of PDA modified MWCNTs reinforcement of Natural Rubber Latex Composites (PDA/MWCNTs/NRL). We found that when the mass ratio of MWCNTs to PDA was 1:0.3, the tensile strength and tear strength of PDA/MWCNTs/NRL composites increased by 25% and 53%, respectively. These results indicated that the surface modification of PDA improved the dispersion of MWCNTs in PDA/MWCNTs/NRL. In addition, combined with the test results and the sliding theory of the rubber macromolecular chain, we first proposed the reinforcement mechanism of MWCNTs in natural rubber matrix composites and described it in detail through pictures.

Stratified diffusion of HOD-D2O inside COOH- and NH2-functionalized multi-walled carbon nanotubes studied by NMR spectroscopy

Functionalized multi-walled carbon nanotubes (MWCNTs) are potential systems for drug delivery applications like cancer therapy. By using NMR spectroscopy, we have demonstrated that 99.8% deuterated water, confined at nanoscale, splits into several components which flow with different diffusion coefficients through MWCNTs having an average diameter of 15 nm. Remarkably, we have highlighted the effect of the functionalization of MWCNTs with COOH- and NH2-molecules on the diffusion of water inside MWCNTs. Our results show that the specific choice of molecules used to functionalize the external surface of MWCNTs allows direct control of the diffusion coefficient. Raman and XPS spectroscopy were used to characterize the structure of MWCNTs after functionalization with COOH- and NH2-.

Cross‐linked tannase‐carbon nanotubes composite in elevating antioxidative potential of green tea extract

Multi-walled carbon nanotubes (MWCNT)-tannase composite was investigated as an immobilized biocatalyst on the basis of its facile preparation, low cost, and excellent aqueous dispersibility. Cross-linked tannase enzymes, obtained in the presence of glutaraldehyde, were composited with MWCNT via physical adsorption. Multiple techniques were applied to investigate, and corroborate the successful adsorption of cross-linked tannase onto the MWCNT structure. Green tea infusion extract post-treatment using the composite preparation showed elevated radical scavenging activities relative to the control. Green tea infusion extract exhibited a markedly reduced EC50 value on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals following its treatment with the enzyme composite, which represents 20%-34% enhancement in its free radical scavenging capacity. Stoichiometry and number of reduced DPPH were determined and compared. The antioxidative potential of a widely consumed, health-beneficial green tea is elevated by the treatment with MWCNT-tannase composite. PRACTICAL APPLICATIONS: Cross-linked tannase enzymes were composited with pristine multi-walled carbon nanotubes via simple physical adsorption. The composite presents key advantages such as low specific volume compared to other well-known immobilization media, inert, facile enzyme composition, and ease of recovery for repeated use. The work demonstrated carbon nanotube prosthetic utility in the biotransformation of food-based health commodity sought after for its nutritional benefits. The approach is of both industrial- and agricultural importance, and is a promising and viable strategy to obtain a natural, functional food supplement for the multi-billion dollar well-being and health-related industries.

Rare earth elements study of Cretaceous coals from Benue Trough basin, Nigeria: Modes of occurrence for greater sustainability of mining

The rare earth elements (REE) possess a beneficial combination of chemical and physical properties, making them valuable for most advanced branches of engineering and technology. Alternative sources of REE are desirable due to limited reserves of conventional REE containing minerals over the world combined with disproportionate supply over demand in the commodity markets. This study investigated the occurrence of REE and carbon nanotubes (CNTs) in Cretaceous Nigerian coals for prospective industrial applications. Results show that the coals’ crystalline mineral matter comprises quartz, kaolinite, and illite with minor quantities of feldspar, hematite, magnetite, calcite, dolomite, which indicate detrital mineral origins. Elemental relationships (such as Al2O3/TiO2, Cr/Th vs. Sc/Th, and Co/Th vs. La/Sc) suggest sediment-source regions with mafic, intermediate or felsic compositions. REE are either strongly fractionated or characterized by light-enrichment along with outlook coefficient (Coutl) values that suggest the coals are prospective substitute sources for REE and yttrium (REY) recovery. Several minerals including jarosite, goethite, epsomite, ferrohexahydrite, natrojarosite, rozenite, and gypsum were detected in trace amounts. REE mineral phases were not identified but only amorphous phases containing Ce, La, Nd, Th, Pr, Sm, Gd, Tb, Dy, Ho, and Hf. Maceral composition (high vitrinite), presence of iron-containing minerals (hematite and magnetite), high carbon contents, reduced volatile matter and low ash content favoured the formation of naturally occurring multi-walled carbon nanotube (MWCNTs) structures in Maiganga (MGA) coal. Hence, the present study is the first scientific report on the naturally occurring REEs and MWC nanophases in Cretaceous coals from the Benue Trough.

Enhancing the Surface Properties and Structure of MWNTs by Effective Ion Beam Irradiation

The effects of irradiating multiwalled carbon nanotubes (MWNTs) with 100 keV He ions on the surface morphology were examined. Due to irradiation effects, the tube diameter reduced as revealed by scanning electron microscopy (SEM). Raman spectroscopy was used to investigate MWNTs by analyzing the principal bands in the spectra of virgin and radiated MWNT specimens. The effects of irradiation fluences on the disorder (D-band) and the graphite (G-band) modes were investigated. The possibility and prospects of using ion irradiation for controlling the wettability of the MWNT surface were investigated. The irradiation facility produces an MWNT coating that is either hydrophobic or hydrophilic to certain liquids. This analysis demonstrates that ion beam irradiation could be used as an alternative tool to change the structure of CNT and enhancing their wettability application, especially in water treatment. According to Raman spectra, when the fluence increases, the MWNTs become disordered due to the defect produced. The amorphous state of MWNTs could be attained with greater ion irradiation fluences.

Evaluation of interactions of multi-walled carbon nanotubes with benzoic acid and its 2-halogeno derivatives and their cytotoxicity

In this study, interactions of multi-walled carbon nanotubes (MWCNTs) with benzoic acid and 2-halogeno (F−, Cl− and Br−) derivatives were investigated. In addition, these compounds were determined to be cytotoxic on Primary Peripheral Blood Mononuclear cells. Adsorption percentages of MWCNTs exposed to these acids at the same concentration for 24 hours were calculated. Raman spectroscopy, Fourier Transform Infrared Spectrocsopy (FT-IR) and Scanning Electron Microscope (SEM) techniques were used to determine the chemical and physical changes caused by acid species on the structure of MWCNTs. As a result of the investigations, it was determined that 2-bromobenzoic acid (BrBA) was adsorbed most favorably by the structure. The structure adsorbed the benzoic acid derivatives better than benzoic acid (BA). The least defect occurred in the sample subjected to BrBA. It was found that there was no correlation between absorption rates and defect occurrences in the structure. SEM results indicate aggregation, tube curl, and filling in inter-tube spaces in samples where absorption is intense. In FT-IR spectra of all structures obtained, the characteristic vibration band related to MWCNTs, and C = O stretching vibration band of the benzoic acid and its derivatives were observed around 1450 and 1680 cm−1, respectively.