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Using the density functional theory, the possible non-covalent interactions and six mechanisms of covalent functionalization of the drug penicillamine with functionalized carbon nanotubes (CNT) were investigated. Quantum molecular descriptors of the non-covalent configurations were studied. It was determined that binding of the drug penicillamine with functionalized CNT is thermodynamically viable. COOH functionalized CNT (NTCOOH) has more binding energy than COCl functionalized CNT (NTCOCl) and could act as a favorable system for penicillamine drug delivery within biological and chemical systems (non-covalent). NTCOOH and NTCOCl can bond to the NH2, OH and SH groups of penicillamine through OH (COOH mechanism) and Cl (COCl mechanism) groups, respectively. The activation energies, activation enthalpies and activation Gibbs energies of six pathways were calculated and compared with each other. The activation parameters related to the COOH mechanism are higher than those related to the COCl mechanism and therefore, the COCl mechanism is suitable for covalent functionalization. These results could be generalized to other similar drugs. nema

A novel class of carbon nanotube (CNT)-based nanomaterials has been surging since 1991 due to their noticeable mechanical and electrical properties, as well as their good electron transport properties. This is evidence that the development of CNT-reinforced polymer composites could contribute in expanding many areas of use, from energy-related devices to structural components. As a promising material with a wide range of applications, their poor solubility in aqueous and organic solvents has hindered the utilizations of CNTs. The current state of research in CNTs—both single-wall carbon nanotubes (SWCNT) and multiwalled carbon nanotube (MWCNT)-reinforced polymer composites—was reviewed in the context of the presently employed covalent and non-covalent functionalization. As such, this overview intends to provide a critical assessment of a surging class of composite materials and unveil the successful development associated with CNT-incorporated polymer composites. The mechanisms related to the mechanical, thermal, and electrical performance of CNT-reinforced polymer composites is also discussed. It is vital to understand how the addition of CNTs in a polymer composite alters the microstructure at the micro- and nano-scale, as well as how these modifications influence overall structural behavior, not only in its as fabricated form but also its functionalization techniques. The technological superiority gained with CNT addition to polymer composites may be advantageous, but scientific values are here to be critically explored for reliable, sustainable, and structural reliability in different industrial needs.

Carbon nanotubes (CNTs) have been widely studied and used for the construction of electrochemical biosensors owing to their small size, cylindrical shape, large surface-to-volume ratio, high conductivity and good biocompatibility. In electrochemical biosensors, CNTs serve a dual purpose: they act as immobilization support for biomolecules as well as provide the necessary electrical conductivity for electrochemical transduction. The ability of a recognition molecule to detect the analyte is highly dependent on the type of immobilization used for the attachment of the biomolecule to the CNT surface, a process also known as biofunctionalization. A variety of biofunctionalization methods have been studied and reported including physical adsorption, covalent cross-linking, polymer encapsulation etc. Each method carries its own advantages and limitations. In this review we provide a comprehensive review of non-covalent functionalization of carbon nanotubes with a variety of biomolecules for the development of electrochemical biosensors. This method of immobilization is increasingly being used in bioelectrode development using enzymes for biosensor and biofuel cell applications.

Carbon nanotubes (CNTs) have been recognized as a promising material in a wide range of applications from biotechnology to energy-related devices. However, the poor solubility in aqueous and organic solvents hindered the applications of CNTs. As studies have progressed, the methodology for CNT dispersion was established. In this methodology, the key issue is to covalently or non-covalently functionalize the surfaces of the CNTs with a dispersant. Among the various types of dispersions, polymer wrapping through non-covalent interactions is attractive in terms of the stability and homogeneity of the functionalization. Recently, by taking advantage of their stability, the wrapped-polymers have been utilized to support and/or reinforce the unique functionality of the CNTs, leading to the development of high-performance devices. In this review, various polymer wrapping approaches, together with the applications of the polymer-wrapped CNTs, are summarized.

CNT nanoparticles have high tensile strength, excellent thermal transfer properties, and optimal chemical and physical stability. The lack of CNT stable dispersion in most of the fluids limits its industrial exploitation in heat transfer applications. Researchers are constantly making efforts for preparing stable dispersions of CNT. Luckily, the unique π-electron-rich structures of CNT open a variety of possibilities for modifications in their structure leading to alterations in their chemical and electronic properties. Normally, chemical and physical methods are used for CNT surface properties alterations to make it dispersible in various base fluids. This review provides a comprehensive survey of chemical and physical methods used to prepare stable CNT nanofluid as well as methods used to analyse CNT nanofluid stability. Chemical modifications are either done by covalent or non-covalent methods. Covalent methods utilized by researchers include reaction with acids, bases, organic and inorganic molecules, metals, metal complexes, polymers, etc. In non-covalent method, surfactants, biomolecules and natural products, polymers, IL and DES, polymers, etc. are used. Physical methods discussed herein include techniques like homogenization, crushing, etc. that deagglomerate CNT bundles. The application of extreme forces on CNT leads to distortion in electronic framework of CNT. Therefore, to avoid excess of physical and chemical treatments, a blend of techniques in appropriate ratio is proposed for CNT dispersion. The techniques that are used to analyse the stability of nanofluid such as UV–vis, TEM, SEM, turbiscan, zeta, and DLS are also reviewed. It could be concluded that there is need for development of low-cost and fast method for prediction of the stability of CNT nanofluid.

Graphene, which is made up of single-layer sp2 graphite, has stimulated the interest of researchers in a variety of application fields, including electronics, pharmaceuticals, and chemicals, due to its superior properties. Large-scale production of graphene is essential for the material to be viable and widely used. One of the most efficient methods of accomplishing a huge amount at a reasonable cost is to exfoliate graphite to produce graphene. The purpose of this paper is to analyze several exfoliation procedures based on a common mechanical and chemical mechanism, because a detailed analysis of the exfoliation phenomenon can lead to valuable insights about how to generate high-quality graphene more economically by optimizing exfoliation approaches. In this study, the focus is given on the extensively employed mechanical exfoliation, such as micromechanical cleavage method, sonication method, ball milling method, and fluid mechanics method and chemical exfoliation, such as chemical vapor deposition and chemical method. This study will also focus on the chemical functionalization of graphene, such as covalent functionalization and non-covalent functionalization. This review will give a deep knowledge about graphite exfoliation and functionalization phenomenon, which will guide in the right way for commercial bulk graphene synthesis with less defects.

Polymercoated carbon nanotubes (CNTs) provide defectfree interfacial control for sensors, thermoelectric, electrochemical and bio devices. We review roles of coated polymers for applications of polymer-coated CNTs for sensors, thermoelectric, batteries and biological applications.

In this article, we review recent progress concerning the development of sensorial platforms based on graphene derivatives and conducting polymers (CPs), alternatively deposited or co-deposited on the working electrode (usually a glassy carbon electrode; GCE) using a simple potentiostatic method (often cyclic voltammetry; CV), possibly followed by the deposition of metallic nanoparticles (NPs) on the electrode surface (ES). These materials have been successfully used to detect an extended range of biomolecules of clinical interest, such as uric acid (UA), dopamine (DA), ascorbic acid (AA), adenine, guanine, and others. The most common method is electrochemical synthesis. In the composites, which are often combined with metallic NPs, the interaction between the graphene derivatives—including graphene oxide (GO), reduced graphene oxide (RGO), or graphene quantum dots (GQDs)—and the CPs is usually governed by non-covalent functionalization through π–π interactions, hydrogen bonds, and van der Waals (VW) forces. The functionalization of GO, RGO, or GQDs with CPs has been shown to speed up electron transfer during the oxidation process, thus improving the electrochemical response of the resulting sensor. The oxidation mechanism behind the electrochemical response of the sensor seems to involve a partial charge transfer (CT) from the analytes to graphene derivatives, due to the overlapping of π orbitals.

In this work, we demonstrate that both carbon nanotubes (CNT) and graphene nanosheets (G) were successfully modified by π-stacking interactions with a pyrene derivative (PY), yielding the functionalized nanofillers CNT-PY and G-PY, which were subsequently dispersed within an aeronautical epoxy matrix. This functionalization is highly effective in preserving the remarkable electronic properties of carbon nanotubes and graphene nanosheets. At the same time, the non-covalent functionalization reduces the resin viscosity, enabling a more effective dispersion of the nanofillers. This results in improved rheological behavior and an overall enhancement of the structural performance of the nanocomposites compared to the resin containing unfunctionalized carbon nanofillers (CNT and G). Additional improvements are also observed in electrical properties, self-healing efficiency, and thermal stability. In particular, the samples containing functionalized carbon nanotubes (TBD + 1%CNT-PY) and functionalized graphene nanosheets (TBD + 1%G-PY) exhibit higher conductivities—0.391 S/m and 0.1 S/m, respectively—than the samples loaded with unfunctionalized carbon nanotubes (TBD + 1%CNT) and unfunctionalized graphene nanosheets (TBD + 1%G), which show conductivity values of 0.292 S/m and 4.82 × 10−3 S/m, respectively. The functionalized graphene nanosheets (G-PY) display significantly greater thermal stability, with degradation temperatures reaching 670 °C, compared to 310 °C for unfunctionalized ones (G). The functionalized carbon nanotubes (CNT-PY) show a 10% weight loss at 520 °C due to the degradation of the pyrene groups. Significant improvements in the final properties can be achieved when carbon-based nanofillers are homogeneously dispersed in the matrix and the external load is efficiently transferred through strong filler–polymer interfacial interactions, leading to composites with superior characteristics suitable for advanced applications. Tunneling Atomic Force Microscopy (TUNA) highlights the morphological features of the two types of carbon nanofillers, their dispersion within the polymer matrix and the effect of the functionalization on the electrical pathways and conductivity of the samples at both the micro- and nanometer-scale. The measured electrical conductivities are consistent with the electric currents detected at the micro/nanoscale.

Polyvinylidene fluoride (PVDF) nanocomposites filled with polyvinylpyrrolidone (PVP) wrapped carbon nanotubes were prepared via a solution casting technique. The effect of the molecular weight (polymer chain length) of the PVP on the ability to wrap different nanotube structures and its impact towards nanotube dispersibility in the polymer matrix was explored. The study was conducted with PVP of four different molecular weights and nanotubes of three different structures. The composites that exhibit an effective nanotube dispersion lead to a nanotube network that facilitates improved thermal, electrical, and mechanical properties. It was observed that nanotubes of different structures exhibit stable dispersions in the polymer matrix though PVP functionalization of different molecular weights, but the key is achieving an effective nanotube dispersion at low PVP concentrations. This is observed in MWNT and AP-SWNT based composites with PVP of low molecular weight, leading to a thermal conductivity enhancement of 147% and 53%, respectively, while for P3-SWNT based composites, PVP of high molecular weight yields an enhancement of 25% in thermal conductivity compared to the non-functionalized CNT-PVDF composite.