Carboxyl-functionalized Carbon Nanotubes Research Articles

Nanocomposites of MoS2 nanoparticles with carboxyl-functionalized carbon nanotubes and borocarbonitrides nanosheets, and their electrocatalytic hydrogen evolution reaction activity

We report a facile method to generate MoS2/single-walled carbon nanotubes (SWCNT) and MoS2/borocarbonitride (BC6N) composites by mixing MoS2 nanoparticle dispersion with different proportions of carboxyl-functionalized SWCNT and BCN in water. The MoS2/SWCNT and MoS2/BCN composites show higher electrocatalytic H2 evolution performance compared to the individual constituents, the activity increasing with the proportion of MoS2. Among the prepared catalysts, MoS2-SWCNT with a 3:1 ratio of MoS2 and SWCNT exhibits highly positive onset potential (-113 mV vs RHE) and a small Tafel slope (59 mV dec−1) as well as remarkable stability in acid electrolyte. The combination of MoS2 nanoparticles with SWCNT or BCN appears to be a valuable finding with applications in catalysis reactions.

Self-Healing, Self-Adhesive Strain Sensors Made with Carbon Nanotubes/Polysiloxanes Based on Unsaturated Carboxyl-Amine Ionic Interactions.

Strain sensors with high sensitivity, long-term durability, and stretchability are required for flexible and wearable electronic devices. This paper reports a bilayer strain sensor consisting of carboxyl-functionalized carbon nanotubes (CNTs) and ionically crosslinked polysiloxane substrates based on unsaturated acid-amine interactions. Vacuum filtration was adopted to prepare the CNT films (2.74-4.70 μm in thickness) onto the polysiloxane substrates to prepare stretchable conductive strain sensors. The strain sensor exhibited self-healing ability, self-adhesiveness, high sensitivity, linearity, low hysteresis, and long-term durability with a gauge factor of 33.99 at 55% strain. The sensitivity and linearity could be adjusted by the thickness of the CNT layer. A crack-related mechanism was proposed in which increasing the thickness of the CNT layer led to simultaneously enhanced sensitivity and linearity. Finally, we investigated the detection of human activities (bending/unbending of fingers or knees) and subtle motions (coughing and swallowing). The fabricated strain sensor succeeded in meeting various needs with satisfactory sensing performance.

Electrochemical behavior of MOF-801/MWCNT-COOH/AuNPs: A highly selective electrochemical sensor for determination of guanine and adenine

In this work, a novel sensor based on gold nanoparticle-modified zirconium-metal-organic frameworks (MOF-801) and carboxyl-functionalized carbon nanotube (MWCNT-COOH) composite material was built successfully for electrochemical detection of guanine and adenine in DNA sample, which exhibits diverse advantages such as fast, convenience and high efficiency. Guanine and adenine were detected by the cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under the optimal conditions, MOF-801/MWCNT-COOH/ AuNPs/GCE delivered linear DPV responses to guanine in the range of 0.8 ~ 60, 60 ~ 180 μM and the adenine in the range of 0.8 ~ 60, 60 ~ 180 μM with the low detection limit of 0.09 μM for guanine and 0.08 μM for adenine, respectively. The advantages of this method include simplicity, rapidity, high sensitivity, good selectivity as well as low cost. The modified GCE was successfully applied to the analysis of guanine and adenine in DNA samples. • A new electrochemical sensor MOF-801/MWCNT-COOHs/AuNPs/GCE is prepared to simultaneously detecting guanine and adenine. • MWCNT-COOHs and AuNPs greatly improve the conductivity of the sensor and the resulted sensitivity. • This electrochemical sensor has good selectivity and sensitivity.

(Invited) Advanced Catalysts for Efficient Electrochemical Ammonia Oxidation

Ammonia (NH3) has proved to be an effective alternative to hydrogen in low-temperature fuel cells via its direct ammonia oxidation reaction (AOR)(1). However, the kinetically sluggish AOR has prohibitively hindered the attractive direct ammonia fuel cell (DAFC) applications. Here, we report an efficient AOR catalyst, in which ternary PtIrM (M: Ni or Zn) alloy nanoparticles well dispersed on a binary composite support consisting of porous silicon dioxide (SiO2) and carboxyl-functionalized carbon nanotube (PtIrNi/SiO2-CNT-COOH) through a sonochemical-assisted synthesis method (2). The PtIrNi alloy nanoparticles, with the aid of abundant OHad provided by porous SiO2 and the improved electrical conductivity by CNTs, exhibit remarkable catalytic activity for the AOR in alkaline media. It is evidenced by a lower onset potential (∼0.40 V vs reversible hydrogen electrode (RHE)) at room temperature than that of commercial PtIr/C (ca. 0.43 V vs RHE). Increasing NH3 concentrations and operation temperatures can significantly enhance AOR activity of this PtIrNi nanoparticle catalyst. Specifically, the catalyst at the temperature of 80 °C exhibits a much lower onset potential (∼0.32 V vs RHE) and a higher peak current density, indicating that DAFCs operated at a higher temperature are favorable for increased performance.References(1) Adli, N. M.; Zhang, H.; Mukherjee, S.; Wu, G., Review—Ammonia Oxidation Electrocatalysis for Hydrogen Generation and Fuel Cells. Journal of The Electrochemical Society 2018, 165 (15), J3130-J3147.(2) Li, Y.; Li, X.; Pillai, H. S.; Lattimer, J.; Mohd Adli, N.; Karakalos, S.; Chen, M.; Guo, L.; Xu, H.; Yang, J.; Su, D.; Xin, H.; Wu, G., Ternary PtIrNi Catalysts for Efficient Electrochemical Ammonia Oxidation. ACS Catalysis 2020, 10 (7), 3945-3957.

Carbon Nanotubes/Regenerated Silk Composite as a Three-Dimensional Printable Bio-Adhesive Ink with Self-Powering Properties.

In this study, regenerated silk (RS) obtained from Bombyx Mori cocoons is compounded with carboxyl-functionalized carbon nanotubes (f-CNTs) in an aqueous environment for the fabrication of functional bio-adhesives. Molecular interactions between RS and carboxyl groups of CNTs result in structural increase of the β-sheet formation, obtaining a resistant adhesive suitable for a wet biological substrate. Moreover, the functionalization of CNTs promotes their dispersion in RS, thus enabling the production of films with controlled electrical conductivity. The practical utility of such a property is demonstrated through the fabrication of a piezoelectric device implanted in a rat to monitor the breathing in vivo and to be used as a self-powered system. Finally, RS/f-CNTs were used as a printable biomaterial ink to three dimensionally print bilayer hollow tubular structures composed of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and RS. Initial tests carried out by seeding and growing human skin fibroblasts demonstrated that the 3D printed bilayer hollow cylindrical structures offer a suitable surface for the seeded cells to attach and proliferate. In general, the herein proposed RS/f-CNT composite serves as a versatile material for solvent-free dispersion processing and 3D printing, thus paving a new approach to prepare multifunctional materials with potential applications of great interest in sealing biological substrates and implantable devices for regenerative medicine.

Surface functionalization of nylon 66 membrane using para-phenylenediamine and carboxylic functionalized multi-walled carbon nanotubes for removal of calcium ions from aqueous solution

Nylon 66, which is an important membrane class used in manufacturing of chitin and chitosan, have a number of features that can be improved by surface functionalizations into a novel composite structure with support of ultrasound and silica gel (SiG) catalyst in a doubled amidation reaction. Firstly, nylon 66/para-phenylenediamine thin film composite (NP-TFC) is prepared from commercial nylon 66 membrane in an ultrasound assisted hydrolysis-amidation reaction. Secondly, carboxylic functionalized multi-walled carbon nanotubes (MWCNT-COOH) are grafted on the NP fiber in an ultrasound assisted/SiG catalyzed amidation reaction, where para-phenylenediamine (pPD) role is cross-linking. As an excellent result confirmed by either Fourier transform infrared (FTIR), Raman spectrometry or scanning electron microscopic (SEM), bundled MWCNTs bridges are easily built in SiG catalyzed ethanol media to connect nylon 66 fibers at distances of 0.3 to 1 μm. The vacuum filtration test confirmed that as-prepared nylon 66/pPD/MWCNTs structure has superior Ca2+ rejection efficiency to that of original nylon 66.

A first-principles study of the atomic layer deposition of ZnO on carboxyl functionalized carbon nanotubes: the role of water molecules.

The formation of heterostructures that combine a large surface area with high surface activity has attracted the attention of the scientific community due to the unique properties and applications of these heterostructures. In this work, we describe - at the atomic level - the full reaction mechanisms involved in the atomic layer deposition of a hybrid ZnO/CNT inorganic structure. First, the pristine CNTs are chemically activated with a carboxylic acid, a process unique to carbon materials. Diethylzinc (DEZ) and water are used as gas-phase precursors to form ZnO. Our findings show that DEZ is physically adsorbed on the CNTs during the exposure of the first precursor. The ligand-exchange to generate chemisorbed ethyl zinc on the O side of the COOH group needs to overcome an energy barrier of 0.06 eV. This is a very small energy if compared to the values (0.5-0.6 eV) obtained in previous studies for OH functionalized surfaces. The height of the barrier is associated with the C[double bond, length as m-dash]O side, which mediates the H proton's exchange from the OH group to the C2H5 ligand. Furthermore, upon exposure to the oxidizing agent (H2O), ethyl zinc exchanges its last ligand as ethane, and it accepts a hydroxyl group through a self-limiting reaction with an energy barrier of 0.88 eV. Notice that the energy barrier of the second ligand-exchange is larger than of the first. We have also analyzed the effect in the saturation of the second precursor: as the quantity of water molecules increases, the long-range interactions tend to repel them. However, the energy barrier of the second ligand-exchange decreases from 1.53 eV to 0.88 eV for one and two water molecules, showing a clear dependence on the oxidizing agent. Non-covalent interactions are used as a tool to visualize the driving forces that take place during each partial reaction in real space. Our study points out the importance of using the right functionalization agent to achieve a controlled and conformal ALD growth at the initial steps of the formation of hybrid ZnO/CNT structures, as well as the role played by the oxidizing agent to lower the energy barrier on the second ALD step.

Green and plant-based adsorbent from tragacanth gum and carboxyl-functionalized carbon nanotube hydrogel bionanocomposite for the super removal of methylene blue dye

This study aims to prepare a hydrogel bionanocomposite (HBNC) as an efficient adsorbent and introduce it as a suitable replacement for petroleum-based adsorbents. Thus, tragacanth gum (TG), and carboxyl-functionalized carbon nanotube (CFCNT) were used as raw materials. HBNCs were prepared with the aid of ultrasonication, and different methods were employed to characterize them. The surface structures of the HBNCs were altered after the addition CFCNT into TG and exposure to ultrasound, as well. Transmission electron microscopy images showed CFCNTs were well dispersed in TG. Then, the adsorption of methylene blue (MB) was performed using these HBNCs. The removal efficiency was over 80% at optimized conditions. Nonlinear and linear forms of Langmuir, Freundlich, Dubinin-Radushkevich, Sips, and Redlich-Peterson (R-P) were applied to find the proper arrangement of MB onto the adsorbent. Using statistical equations, it was revealed that the process obeyed the linear R-P model, indicating a mixture of mono- and multilayer adsorption (but mostly monolayer). Also, pseudo-second-order was the appropriate kinetic model and suggested chemical adsorption. According to the thermodynamic calculations, this process was exothermic and spontaneous, and the type of interactions between HBNC and MB was physicochemical. Also, the diffusion study indicated that film diffusion is the primary mechanism.

Synthesis-structure-performance relationships of nanocomposite polymeric ultrafiltration membranes: A comparative study of two carbon nanofillers

Many nanoscale fillers have been impregnated in polymeric ultrafiltration membranes in order to augment performance, but their effects on membrane formation, structure, and performance remain fragmentally and poorly understood. In this work, we comparatively studied the effects of two carbon nanofillers (i.e., graphene oxide (GO) and carboxylic-functionalized carbon nanotube (c-CNT)) and established a coherent understanding of the synthesis-structure-performance relationships of such nanofiller-impregnated ultrafiltration membranes. Our results show that the morphological factor, as a result of nanoparticle properties, in addition to thermodynamic instability and rheological hindrance, is an important factor to consider when evaluating the effects of (carbon) nanofiller on membrane formation. Further, we addressed the discrepancy previously observed in rejection performance change after nanofiller addition, and demonstrated that the main benefits of adding carbon nanofillers exist in the enhancement of rejection of negatively charged molecules with increased permeability at low nanofiller mass loading. Our research findings bridge critical knowledge gaps, and provide mechanistic insights into the role and application of nanofillers in membranes.

Pt-Based Ternary Catalysts for Electrochemical Ammonia Oxidation

Ammonia (NH3) has proven to be a cost-effective alternative to hydrogen for powering fuel cells via its direct oxidation to nitrogen and water. However, sluggish kinetics of the ammonia oxidation reaction (AOR) have greatly hindered the commercial application of direct ammonia fuel cells (DAFCs). Here we report an efficient AOR catalyst that consists of PtIrNi alloy nanoparticles anchored on a binary support of porous silicon dioxide and carboxyl-functionalized carbon nanotubes (PtIrNi/SiO2-CNT-COOH) through a sonochemical-assisted synthesis strategy. The PtIrNi alloy nanoparticles, with the aid of abundant OHad provided by porous SiO2, and the improved electronic conductivity contributed by CNT, exhibit remarkable catalytic activity for the AOR in alkaline media, with a lower onset potential (~0.40 V vs. RHE) at room temperature, than that of commercial PtIr/C (~0.43 V vs. RHE). Constant-potential density functional theory (DFT) calculations showed that the Pt-Ir ensembles on {100}-terminated surfaces serve as the active site, the introduction of Ni to which raises the center energy of the density of states projected onto the group d-orbitals and thus lowers the theoretical onset potential for *NH2 dehydrogenation to *NH when compared to Pt and Pt3Ir alloy. Varying the NH3 concentration and operation temperature shows a significant influence on the AOR performance of this catalyst. Specifically, AOR activity of the optimal PtIrNi nanoparticle catalyst can be significantly enhanced by elevating the temperature to 80ºC, with a much lower onset potential (~0.32 V vs. RHE), indicating that DAFC can be operated at higher temperature for increased performance.

Binding Capacity and Selectivity of Functionalized and Un-functionalized Carbon Nanotubes for Development of Copper-Detecting Printable Sensor.

Carbon nanotubes (CNTs) have unique properties which can be modified through surface functionalization. The ability of several functionalized and un-functionalized CNTs to bind copper was investigated as a first step toward developing a printable CNT-based sensor to detect copper in aqueous systems. Binding capacity and specificity were shown to vary by functionalization and vendor. CNTs from two vendors were tested, and the equilibrium binding data was fitted using two isotherm models. Calculated qmax (mg/g) values indicated one vendor's carboxyl-functionalized CNTs had the greatest binding capacity (94-115mg/g), while other carboxyl-functionalized CNTs and amine-functionalized CNTs had similar capacities to un-functionalized CNTs (15-30mg/g). Hydroxyl-functionalized CNTs had the lowest copper binding capacity (7-8mg/g) of the CNTs tested. Freundlich isotherms showed no obvious trends in binding affinity, but suggested that binding was primarily due to chemisorption. Variations in CNT size, functionalization percentage, and purity could explain, partially, the observed adsorption differences.

Impedance spectroscopy of polyvinyl alcohol-coated carboxyl-functionalized single-walled carbon nanotube flexible film: a generic battery model

In this study, we demonstrate a simple technique to prepare a flexible single-walled carbon nanotube (SWCNT) array for battery application. The polyvinyl alcohol-coated unidirectional SWCNT flexible film has been prepared using a simple solution casting technique. The frequency variation of impedance spectroscopy of the composite film is investigated in a frequency spectrum of 20 Hz ≤ f ≤ 1 MHz and temperature range (373 ≤ T ≤ 413 K). The experimental data are simulated with a generic battery model equivalent circuit. The generalized model is based on impedance spectroscopy, which is suitable for practical application and able to interpret the existing battery model. The extracted parameters from the simulation of experimental data are tabulated. The temperature variation of the parameters is very significant for manufacturing a battery system. The study of electric modulus suggests a non-Debye-type relaxation behavior of the flexible battery system.

Interfacial growth of metal-organic framework on carboxyl-functionalized carbon nanotubes for efficient dye adsorption and separation.

Hybrid nanocomposites based on UiO-66-NH2 and carboxyl-functionalized carbon nanotubes were developed in this study via different synthetic pathways. Combining them through interfacial in situ growth was beneficial for the better dispersity of UiO-66-NH2 in the CNTs@UiO-66-NH2 composite than physically mixing CNTs/UiO-66-NH2 and chemically bonded CNTs-CONH-UiO-66. Coordination between carboxyl groups of CNTs and zirconium ions resulted in the interfacial growth of UiO-66-NH2 on CNTs. Adsorption experiments showed that CNTs@UiO-66-NH2 exhibited the highest adsorption efficiency towards methyl orange (MO). The adsorption capacity of CNTs@UiO-66-NH2 was up to 392 mg g-1, which was 77.45% and 201.5% higher than those of CNTs-CONH-UiO-66 and CNTs/UiO-66-NH2 respectively. Moreover, CNTs@UiO-66-NH2 could selectively adsorb MO from the MO/MB mixture.

Platinum nanoparticle-carbon nanotubes dispersed in gum Arabic-corn flour composite-enzymes for an electrochemical sucrose sensing in commercial juice

The aim of the present study was to fabricate a rapid analytical platform for the analysis of saccharide in foods using new bio-composite of nanomaterials in the natural polysaccharides, gum Arabic (GA) and corn flour (CF). The hydrogel was reinforced by metal nanoparticles (PtNPs) anchored with carboxyl-functionalized carbon nanotubes (MWCNTs). The GA-CF composite was investigated for the possibility of co-immobilization of Invertase (Inv) and glucose oxidase (GOx). Physical immobilization of Inv-GOx in the form of thin film resulted in high enzyme retention efficiency (Inv-96.5% and GOx-92%) with excellent storage stability, up to 6 months at room temperature, for both enzymes. The resulting bioactive films were studied for various physicochemical parameters including reproducibility, pH, nanomaterial loading capacity, operational stability, and shelf life. The morphological characterization of the nanocomposite was examined by transmission electron microscopy, and it revealed that the diameter of PtNPs changed from ~ 3.0 to 21 nm due to outer surface coating after immobilization. Uniform dispersion of carbon nanowire network embedded in bi-enzymes/GA-CF composite film was also observed under scanning electron microscopy. Entrapment of MWCNTs and PtNPs in GA-CF carrier resulted in an improved catalytic efficiencies and loading capacity of both enzymes due to larger surface area for entrapment. Screen-printed carbon electrodes (SPCEs) were modified with this novel enzyme-nanocomposite matrix and an electrochemical biosensor (Inv-GOx-MWCNTs-AgNPs/SPCE) was thus developed. The biosensor exhibited excellent sensitivity, good reproducibility, long-term stability, fast amperometric response to sucrose with wide linear range of 1 × 10−4 to 1 × 10−9 mol L−1 with a correlation coefficient of 0.99, and better limit of detection (1 × 10−9 mol L−1) as compared to previous sensors. The sucrose analytical capabilities of the sensor were tested on commercial fruit, vegetable, and mix juice samples, and the validity of the measurement was confirmed by standard DNSA method.

HYDROXYAPATITE - CARBON NANOTUBE COMPOSITES FOR DRUG DELIVERY APPLICATIONS

Abstract The aim of this study was the synthesis of composites containing hydroxyapatite (Hap) or silicon substituted hydroxyapatite (HapSi), carboxyl functionalized carbon nanotubes (fMWCNT) and gelatin (G) in different ratios. Ibuprofen (IBU) was chosen as a model drug for the formulation of extended-release dosage forms. The obtained composites were characterized using X-ray diffraction, laser diffraction particle size analyzer, Brunauer-Emmett-Teller surface area measurements, transmission electron microscopy and Fourier transformed infrared spectroscopy. IBU adsorption and desorption was monitored by UV-VIS spectroscopy. The obtained results revealed that composites containing three components exhibit higher adsorption efficiency (Hap-fMWCNT-20G - 82.7% and HapSi-fMWCNT-20G - 84.6%) and extended-release of IBU, due to the chemical bonds between the carboxyl groups of IBU and the functional groups on the composite surface. The adsorption capacity of Hap composites is important for dental or orthopedic implants, the anti-inflammatory substances being adsorbed on their surface; but the adsorption capacity also enhances new bone formation (osteosynthesis) around the implants. These composites are thus attractive materials to be used in bone tissue engineering and drug delivery systems.

Induction of caspase-2 gene expression in carboxyl-functionalized carbon nanotube-treated human T-cell leukemia (Jurkat) cell line

Carbon nanotubes (CNTs) have great potential as novel diagnostic or therapeutic tools in biomedicine but, cellular toxicity must be well considered before widespread application of CNTs. Many chemical agents exert their toxicity through apoptotic pathways by induction of caspase biomolecules. In the current study, effects of carboxyl-functionalized single-walled (SW) and multi-walled (MW) CNTs at a single dose of 100 µg ml−1 on the survival of Jurkat cells were examined using MTT assay. Additionally, the impacts of carboxylated CNTs on the gene expression levels of selected caspases were investigated. Jurkat cells were exposed to CNTs (100 µg ml−1 for 72 h) and then expression levels of selected caspase genes (Cas) were evaluated by qRT-PCR analysis. Housekeeping genes, β-actin, and glyceraldehyde 3-phosphate dehydrogenase (GAPDH), were used as normalization controls. The results showed only a mild decrease in the viability of Jurkat cells treated with carboxylated MWCNT. The results of qRT-PCR analysis revealed the elevated level of Cas2 mRNA in the cells treated with carboxylated MWCNT (6.08-fold) and carboxylated SWCNT (1.20-fold). The expression levels of Cas4, Cas6, Cas8, and Cas10 genes were increased not significantly compared to the control untreated cells. Our findings suggested that exposure to carboxyl-functionalized CNTs could be resulted in up-regulation of the Cas2 gene and not initiator Cas8 and Cas10 genes. In addition, it seems that carboxylated MWCNT was more potent than SWCNT in activation of Cas2 gene expression and triggering cell death signal in a manner different from intrinsic or extrinsic apoptosis pathways.

Improving interfacial and mechanical properties of carbon nanotube-sized carbon fiber/epoxy composites

Carboxyl-functionalized carbon nanotubes (CNTs-COOH) and the amine-functionalized carbon nanotubes (CNTs-NH2) were incorporated into the surface sizing agent of carbon fibers respectively, for modifying the interface between the fibers and the matrix. Experimental analyses of the interfacial shear strength, flexural properties, and inter-laminar shear strength revealed the beneficial effects of the CNTs-COOH and negative impacts of the CNTs-NH2 on the interfacial and mechanical properties of the resulting composites. These results were contrary to the effects of CNTs doped into the epoxy matrix of composites. Furthermore, a molecular dynamics simulations were performed to explore the mechanism of these performances from the viewpoint of the molecular structure, revealing that the interface between the CNT-sized carbon fibers and the epoxy was driven by multiple factors, including the CNT-epoxy interfacial binding energy (IBE), the packing density of the molecular chains, and the steric hindrance of the functionalized CNTs. According to these analyses, two kinds of functionalized CNTs showed different effects at the interface between carbon fiber and resin: the CNTs-COOH on the surface of the carbon fiber tightly bonded to the epoxy and provided effective load transfer between the matrix and fibers, whereas the agglomeration of the CNTs-NH2, the lower IBE between the CNTs-NH2 and the epoxy resin, and the steric hindrance produced by amine functional groups of the CNTs-NH2, resulting in hardly inhibiting the crack growth of the matrix under stress.

Stabilization of d-lactate dehydrogenase diagnostic enzyme via immobilization on pristine and carboxyl-functionalized carbon nanotubes, a combined experimental and molecular dynamics simulation study

The most important mode of enzyme inactivation is thermal inactivation. Immobilization technology is an efficient approach to elongate the life-time of enzymes. d-lactate dehydrogenase (D-LDH) was stabilized at high temperatures with immobilization on CNT and fCNT. The kinetic and thermodynamic parameters, optimum temperature and pH, and the intrinsic fluorescence of free and immobilized enzymes were examined in the present study. Also, an attempt was made to investigate the effect of CNT and fCNT on the adsorption and conformation of d-lactate dehydrogenase using molecular dynamics (MD) simulations. In comparison with free enzyme, the immobilized enzyme displayed an improved stability at high temperatures and, therefore, the immobilized enzyme is suitable for use in the industry because most reactions in the industry happen at high temperatures. Results of the present study showed that the adsorption of enzyme on CNT is mediated through the van der Waals and π-π stacking interactions, whereas in the adsorption of enzyme on fCNT in addition to hydrophobic interactions, the hydrogen bonding between enzyme and functional groups of fCNT is involved. Moreover, RMSD, RMSF and secondary structure analysis indicate that the fCNT protects the conformation of enzyme more than CNT. Therefore, D-LDH can be efficiently immobilized upon the fCNT compared to the pristine CNT.

Self-similar arrays of carbon nanotubes and nonwoven fibers with tunable surface wettability

Self-similar materials can assist in the transition of hydrophobic to hydrophilic state in a well-controlled manner. Herein, we report an ensemble of carboxylic functionalized carbon nanotubes (CNTs) decorated on the self-similar nonwoven surface using a facile, scalable and inexpensive vacuum filtration process for tunable surface wettability. Increasing the amount of CNTs combined with the vacuum assisted nonwoven material reduced the apparent equilibrium contact angle systematically. A simple analytical model has been proposed to predict the apparent equilibrium contact angle by formulating a direct relationship with the structural parameters of CNTs and nonwoven materials. In general, a satisfactory agreement was observed between the theoretical and experimental apparent equilibrium contact angles of CNT decorated nonwoven materials.

π‐Plasmon absorbance films of carboxylic functionalized CNTs coupled with renewable PGP platforms

π‐Plasmon absorbance films of carboxylic functionalized multiwall carbon nanotubes (CNTs) coupled with renewable and recycled polycaprolactone grafted pectin (PGP) platforms as successful alternative for ordinary nondegradable platforms were investigated. Characterization of the synthesized carboxylic functionalized CNTs was performed using 1H NMR and attenuated total reflectance Fourier transform infrared for structural identification, thermogravimetric analysis and derivative thermogravimetric analysis for thermal stability, and X‐ray powder diffraction for crystal structure, whereas the characterization of prepared PGP was done by means of attenuated total reflectance Fourier transform infrared for chemical structure, differential scanning calorimetry for melting endotherms of polycaprolactone and high crystalline structure of PGP, and thermogravimetric analysis and derivative thermogravimetric analysis for thermal stability of PGP. Fabrication of water‐dispersed carboxylic functionalized CNTs coupled with PGP films was performed by casting technique in the presence of Ca2+ as cross‐linker. The thin films were tested for π‐plasmon absorbance using UV‐Vis spectrometry. Different fractions of carboxylic functionalized CNTs and PGP films demonstrated π‐plasmon absorbance broad peaks at λmax = 232 nm, which corresponded to 5.36 eV. The fabrication of novel films from renewable recycled PGP platform and advanced carboxylic functionalized CNTs properties will be the key features for many of next forthcoming technologies. The PGP considered as environment‐friendly and easily degradable platforms will be a successful alternative for conventional nondegradable electronic platforms, and water‐dispersed carboxylic functionalized CNTs with advanced properties will be finding accelerating executive applications.