CARBON NANOTECHNOLOGY

- By ANISH KUMAR 

- Batch (2k20) ,Deptt. of 

Chemical Engg.

- BIT Sindri ,Dhanbad

Introduction:

Carbon nanoparticles are being explored widely for use in different applications. For example, it is well known that the electrical conductivity of polymer materials can be considerably improved by incorporation of conductive fillers such as carbon nanoparticles. Note that these particles can also be used in human cancer treatments. In fact, carbon black (CB) has been known for more than a century in the reinforcement of rubber in automotive tire applications. More recently and since the synthesis of large aspect ratio and multifunctional carbon fillers such as carbon nanotube (CNTs) and graphene derivatives, carbon nanoparticles has attracted increasing attention  in many industrial domains. Generally speaking, a direct consequence of filler incorporation in molten polymers is the significant change in viscoelastic behaviors as they are sensitive to the structure, concentration, particle size, shape (aspect ratio) and surface modification of the fillers. As a result, rheological methods are useful and suitable to assess the quality of filler dispersion . In recent years, nearly all types of nanofillers have been used for the preparation of nanocomposites: organoclays, CB, fumed and colloid silica, CNTs, cellulose whiskers, metallic oxide, etc., and more recently, graphite oxide and graphene.

From a literature survey, thousands of papers and reviews have been published in this broad scientific area. However, carbon nanoparticles (CB, CNT and graphene derivatives) has been extensively studied due to their ability to improve the electrical conductive properties of polymer nanocomposites. It is well known that the morphological control of nanoparticles has a crucial influence on the final properties. In fact, the morphology and the internal structure of these nanoparticles are of importance to understand the final properties. Figure shows the morphology from transmission electronic microscopy (TEM) of carbon nanoparticles. As explained by Dang ., the CB primary particles are structured at different scales (aggregation) due to strong interaction among the particles which results in chain-like structures. This type of strong interaction of particles leads to apparent elongated particles which have a larger interacting volume than spheres with the same particle volume in weakly structured CBs. CNTs are expected to achieve their percolation threshold at low filler volume fractions due to the high aspect ratio (generally L/D>> 100). Indeed, percolation thresholds as low as 0.06 wt.% have been reported in the literature for CNT–polymer systems. Regarding graphene nanoparticles in, there can be observed as in CB an aggregation of the graphene sheets at different scales. From a physics point of view, the percolation threshold, the transition between insulator–conductor or between liquid–gel, depends on the nature of these carbon nanoparticles. There can then be expected the following classification in terms of the percolation threshold concentration: CNT<Graphene<CB from the lowest to the highest value. However, the dispersion and control of the aggregation at different scales are of importance to control this percolation threshold and the final properties.

 

 

 

 Application of Carbon-Based Nanomaterials as Drug and Gene Delivery Carrier

Nanotechnology is one of the most exciting disciplines that applied to improve the therapeutic indices by the carbon nanomaterials. Their unique physical and chemical properties make them interesting candidates of research in a wide range of areas including biological systems and different diseases. Recent research has been focused on exploring the potential of the carbon nanomaterials as a carrier or vehicle for intracellular transport of drugs, proteins, and targeted genes in vitro and in vivo. Several research groups are actively involved to find out a functional carbon nanomaterial carrier capable of transporting targeted drug molecules in animal models with least toxicity. This chapter is focused on carbon nanotubes, graphene, and carbon quantum dots, which appear to be promising agents for successful delivery of biomolecules in various animal models. But potential clinical implementations of carbon nanomaterials are still hampered by distinctive barriers such as poor bioavailability and intrinsic toxicity, which pose difficulties in tumor targeting and penetration as well as in improving therapeutic outcome. This chapter presents the progresses in the design and evaluation of closely related carbon nanomaterials for experimental cancer therapy and explores their implications in bringing nanomedicines into the clinics.

 

 

 

Carbon-based electrodes as a scaffold for the electrochemical sensing of pharmaceuticals: a special case of immunosuppressant drugs

 

Carbon nanoparticles are extensively utilized for the modification of the electrode surface, as these possess exceptional properties due to the high surface-to-volume ratio. The widespread use of carbon-based nanomaterials in the electrode modification process is due to the formation of a layered structure with the strong sp² carbon bonds on the surface of the transducer. This property of carbon-based nanomaterials explains its least electrical resistance and the ability to form the charge transfer complexes with the electron donating functional groups. Carbon nanotubes (CNTs), both single walled and multiwalled, were extensively used for modifying electrodes in the electroanalytical techniques after their first invention by Sumio Iijima. The high electrical conductivity, exceptional electrocatalytic activity, and superior biocompatibility make CNTs a hot subject in the modification process for the development of novel electrochemical sensors. The graphene is also a propitious candidate in the fabrication of modified electrodes for various electrochemical sensing applications. Graphene, a two-dimensional nanomaterial of carbon was highly exploited in the construction of electrochemical sensors for biomolecules and pharmaceuticals due to its exceptional and unique properties like high thermal conductivity, fast electron transport, and flexibility in the mechanical properties. Reduced graphene oxides also have been altering the electrode surface in the frontiers of electrochemical sensing due to colossal surface area, electrocatalytic activity, and exquisite electrical conductivity. Nanodiamond, another carbon material entirely different in properties from large diamonds, is an emerging and attractive material in the electrochemical sensing research. Its higher conductivity due to the delocalized π bonds and its ability to form stable dispersions in aqueous media makes it attractive for exploit in the field of electrochemical sensors for pharmaceuticals.

Fullerene (C₆₀), is another fascinating carbon material amply used for electrocatalytic and sensor applications. The electrochemistry of fullerenes is a widely studied topic in electrochemical research. Electrochemical sensors exploring the properties of fullerenes have already been reported in various pharmaceutical applications.

 

Application of Carbon Based Nano-Materials to Aeronautics and Space Lubrication

Carbon nanoparticles and carbon films, such as diamond and graphite-like carbons, are making new inroads into lubrication applications. The carbon-based nanoparticles are heat resistant, radiation hard, and durable and provide low coefficient of friction (CoF) with a number of tribocouples. A careful examination of the internal structure of the carbon materials reveals that the nanostructure is highly variable and depends upon the starting material and processing conditions—which is also true of carbon black. The significance with respect to oxidation of the internal structure of carbon is its effect upon reactivity. Graphitic carbon is characterized by layer planes with large in-plane dimensions. The connection between layer plane dimensions and oxidation is due to the anisotropic reactivity of the graphitic segments comprising carbon. Carbon atoms within basal plane sites, surrounded by other carbon atoms, exhibit a far lower oxidative reactivity than those located at the periphery of such segments.

 

 

Catalysis with carbon nanoparticles

 

Carbon nanoparticles (CNPs) represent a recent class of nanomaterials, based on carbon sp² atoms in the inner core. These new nano-dots cover a wide range of application fields: analytical, sensing and biosensing, bioimaging, theranostic, and molecular communication. However, their use as nanocatalysts is relatively new. Although CNPs can be easily synthesized and obtained in good amounts, few reports on their catalytic applications have been reported. This minireview collects the use of these nanoparticles as catalysts highlighting the improvements with respect to the classic catalytic systems. In particular, due to their unique optical and electrical properties, and due to the possibility to cover the external shell with a wide variety of functional groups, CNPs have found catalytic applications in three main classes of reactions: (i) photocatalysis, (ii) acid–base catalysis and (iii) electro catalysis.

 

 

Carbon nanoparticles (CNPs) represent a recent class of nanomaterials, based on carbon sp² atoms in the inner core. These new nano-dots cover a wide range of application fields: analytical, sensing and biosensing, bioimaging, theranostic, and molecular communication. However, their use as nanocatalysts is relatively new. Although CNPs can be easily synthesized and obtained in good amounts, few reports on their catalytic applications have been reported. This minireview collects the use of these nanoparticles as catalysts highlighting the improvements with respect to the classic catalytic systems. In particular, due to their unique optical and electrical properties, and due to the possibility to cover the external shell with a wide variety of functional groups, CNPs have found catalytic applications in three main classes of reactions: (i) photocatalysis, (ii) acid–base catalysis and (iii) electro catalysis.

Treatment Delivery

Carbon nanoparticles can be used for the delivery of drugs at a cellular level. One research team used carbon nanoparticles created through basic means to deliver infusions of drugs to a pig. The conclusion from that experiment is that carbon nanoparticles could be used to deliver a variety of drugs to treat cancer.

Specifically, the research team believes nanoparticles could deliver medicine to melanoma cells. The same premise behind the research could possibly be used to deliver treatment to all types of cancer cells, and as research continues, to delivery medication or treatments for any disease that functions at a cellular level.

One of the benefits of carbon nanoparticles is that delivery isn’t limited to one type of treatment. By coating the nanoparticles with different polymers, labs could load particles with multiple drugs for multitherapy treatment that is fast, cost-effective, and mostly noninvasive.

Researchers are also working to develop carbon nanoparticles that can deliver gene therapies or trace genes for increased understanding of certain disease processes.

 

 

 

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