Incorporation Of Carbon Nanomaterials Research Articles

Investigation of non-covalent interactions in Polypyrrole/Polyaniline/Carbon black ternary complex for enhanced thermoelectric properties via interfacial carrier scattering and π-π stacking.

The thermoelectric (TE) performance of conducting polymers can be improved by the incorporation of carbon nanomaterials. In this work, the impact of carbon black (CB) on polypyrrole (PPy) and polypyrrole/polyaniline (PPy/PANI) binary composite have been investigated. Herein, PPy/PANI binary composite was initially prepared through chemical oxidative polymerization and then solution mixed with CB to form PPy/PANI/CB ternary nanocomposite. The structural and morphological analyses confirmed the formation of composites, and the strong interaction present between polymer matrix and CB. This was further confirmed by theoretical study, which showed strong noncovalent interaction and high complex stability between the materials. The thermoelectric results showed that both the electrical conductivity (σ) and Seebeck coefficient (S) has been increased with the increase in CB content (from 10wt% to 30wt%) and temperature (303K to 373K), while the thermal conductivity (κ) increase was low. The ternary nanocomposite involving 30wt% of CB was found to be the most promising material which showed an enhanced power factor (PF) of 0.0251μW/mK2 and high figure of merit (ZT) of 4.37x10-5 at 370K. The enhancement in ZT for PPy/PANI/CB ternary composite is 2 times, 316 times, 17.3 times, 3.97 times, 11.7 times, and 6.8 times greater than other samples. The enhancement in power factor and ZT was due to energy filtering effect and strong non-covalent interactions between the homopolymers and CB.

Electrodeposition of Si on Cu Substrate As Anode for Li-Ion Battery Application

Lithium ions battery (LIBs) has been considered as one of the furthermost capable power sources in the portable electronic devices and electric vehicles.1 Silicon (Si) is a promising negative electrode material for LIBs, owing to its cost-effectiveness, non-toxicity, and high specific capacity of 4200 mAhg-1.2 The main challenges of applying Si-based LIBs are low electronic conductivity (≈10−4 S m−1) 3 and volume expansion (~ 300%) during the charge-discharge process.4,5. For a sustainable and practical approach, room temperature (RT) methods are an essential requirement. Recent studies suggest that the aqueous phase synthesis of Si-nanoparticles affects its phase purity, therefore the use of ionic liquids (ILs) as media for the electrodeposition of Si-nanostructures can resolve sustainability issues. In this work, electrodeposition of Si-nanoparticles on Cu substrate was successfully fabricated in the ILs media (1-butyl-3-methylimidazolium-bis (trifluoromethyl sulfonyl) imide (BMImTf2N)) at room temperature.Cyclic voltammetry (CV) revealed the sequential reduction of Si4+ to Si2+ followed by Si2+ to Si-nanoparticles (SiNPs). The morphology of the electrodeposited SiNPs from 1 M SiCl4 in BMImTf 2 N at room temperature on Cu substrate is shown in Fig. 1 (a). The electrodeposited SiNPs were interconnected with an average particle size of ⁓50-70 nm. The X-ray photoelectron spectroscopy (XPS) data of surface compositions of the electrodeposited SiNPs showed peak at 99.1 eV for elemental Si (Fig 1 (b)). Further, X-ray diffraction (XRD) analysis of SiNPs revealed sharp peak at 28.7° for the crystalline Si (111) phase (JCPDS NO: 800005; Fig 1(c)). The first discharge and charge capacity of Si anode material have been found to be 2386 and 2300 mAhg-1, respectively, at a high current density of 4 Ag-1 (Fig 1(d)). The initial irreversibility of discharge-charge process can be attributed to the solid electrolyte interface (SEI) formation via electrolyte decomposition and trapped Li+ into inner pores of SiNPs. After 10 cycles, charge-discharge profiles have been stabilized, with a reversible capacity of 2286 mAhg-1 at 4 Ag-1 current density. The stabilization of charge-discharge capacity may be due to stable SEI formation. The coulomb efficiency (CE) of first cycle was 96 %, which improved to 98 after 10 cycles. The high CE is attributed to the reversible kinetics of the Li + ion on the SiNPs in the charging and discharging process. The high surface area of SiNPs accommodates the volume expansion and stabilizes SEI layer. The reversible capacity 2286 mAhg-1 is only ~ 5 % less than that of first discharge capacity. The retention of very high reversible capacity with respect to the initial discharge capacity shows that SiNPs of crystalline (111) phase orientation is a promising material for LiBs. The effect of SEI formation and battery testing on the electrical conductivity of SiNPs was investigated by electrochemical impedance spectroscopy (EIS). The resistance due to SEI formation (RSEI) was increase from 27 Ω to 30 Ω after 100 charge-discharge cycle. The large volume expansion during charge-discharge leads to pulverization of SiNPs, and hence electrical conductivity of SiNPs was decreased. However, charge-discharge data suggests that there is only ~ 5 % decrease in discharge capacity from the first cycle, demonstrating the improvement of the interfacial charge transfer kinetics. The pure electrical conductivity of Si can be improved by the incorporation of CNTs for stable SEI formation and accommodate large volume expansion during charge-discharge cycle. In summary, we have demonstrated the electrodeposition of SiNPs with controllable size in the presence of water contaminated RTILs. The electrodeposited SiNPs shows high reversible charge capacity of ~ 2286 mAhg-1 and stability up to 100 cycles at high current density of 4 Ag-1. The specific charge capacity is further improved by incorporation of carbon nanomaterials and tuning of current density. Figure 1

Polyvinyl alcohol/polyethersulfone thin-film nanocomposite membranes with carbon nanomaterials incorporated in substrate for water treatment

A new class of thin-film nanocomposite (TFN) nanofiltration (NF) membrane was synthesized successfully by incorporation of carbon nanomaterials (oxidized multi-walled carbon nanotube (O-MWCNT) and graphene oxide (GO)) into polyethersulfone (PES) substrate via phase inversion method, substrate surface coating with polyvinyl alcohol (PVA) and then cross-linking with glutaraldehyde (GA). For better comparison, thin-film composite (TFC) membranes (without carbon nanomaterials incorporation into PES substrate) were also synthesized and the optimum concentrations of PVA and GA solutions were obtained. The fabricated TFC and TFN (TFN/O-MWCNTs and TFN/GO) membranes were characterized by SEM, AFM, ATR-IR spectroscopy and contact angle measurements. It was found that incorporation of O-MWCNTs and GO into the PES substrate results in more elongated finger-like pores and larger macrovoids in the substrate and also reduced thickness of the thin skin layer and roughness of the membrane surface. The optimum TFC membrane showed pure water flux of about 13.2 LMH and Na2SO4 rejection of 84 % at 4 bar, while the TFN/O-MWCNTs and TFN/GO membranes showed 54 % and 35 % improvement in water permeability, respectively, without immolating Na2SO4 rejection. The rejection sequence was obtained as R (Na2SO4) > R (MgSO4) > R (NaCl) that confirms the membranes surface has negatively charge.

Enhancement of Electrical Conductivity of Electrospun Polyacrylonitrile Fibres Using Carbon Nanomaterials Synthesised from Polypropylene Waste

Incorporation of carbon nanomaterials (CNMs) into polymer such as Polyacrylonitrile (PAN) fibres allow electric current to pass through easily. Therefore in this study, bulk quantities of CNMs are synthesised using Chemical Vapor Deposition (CVD) method by manipulating the reaction time and catalyst ratio. Polypropylene wastes are used as the carbon precursor and ferrocene as metal catalyst in the CVD experiment. Addition of 1 wt% synthesised-CNMs into electrospun PAN fibres successfully increased the electrical conductivity by 50%. Addition of CNMs improved the crystallinity of electrospun-PAN/CNMs fibres as proven by XRD analysis. Electrospun PAN/CNMs-A fibres show larger diameter than the diameter of electrospun PAN/CNMs-B. Large bead formations contained densely-packed CNMs-A within the structure of electrospun PAN/CNMs-A fibres hindered their effectiveness to conduct the electricity. On the contrary, PAN/CNMs-B shows remarkable improvement in electrical conductivity when loosely-packed CNMs-B are added to the PAN fibres.

A mechanistic approach for the modulation of band gap of nanopolyaniline using various heterogeneous carbon nanostructures

The present work introduces a mechanistic approach for the synthesis of nanopolyaniline (nPANI) and modulation of its band gap using various carbon nanostructured materials. Carbon-based different nanostructures, viz. graphene oxide, reduced graphene oxide and multiwall carbon nanotubes, have been incorporated in situ for the preparation of nanocomposites. Polyethylene glycol (PEG)-based non-ionic surfactant-assisted oxidative polymerization of aniline was implemented. The major concern of this study is to present a possible mechanism and chemistry for the development of the nanomaterials (nPANI and its nanocomposites) and further the effect of heterogeneous carbon nanomaterials on both types of band gaps (optical and electrochemical) of nPANI in the presence of PEG. First time a comparative study between optical and electrochemical band gap has also been done to analyze the effect of carbon nanomaterials on nPANI. The prepared samples were characterized by Field-emission scanning electron microscopy, Fourier transform-infrared spectroscopy and X-ray diffraction. Electrochemical and optical properties were assessed by cyclic voltammetry (CV) and ultraviolet–visible spectroscopy (UV–Vis), respectively. The electrochemical ( $$E_{\text{g}}^{\text{CV}}$$ ) and optical ( $$E_{\text{g}}^{\text{opt}}$$ ) energy gap of nPANI was evaluated as 2.74 and 2.34 eV by CV and UV–Vis quantification, respectively. It was observed that incorporation of carbon nanomaterials at lower percentage improves $$E_{\text{g}}^{\text{CV}}$$ of nPANI to as minimum as 2.34 eV as per the CV data. Schematic energy diagram showing the band gap reduction and electron transport mechanism using CV has also been presented.

Material Characterization and Bioanalysis of Hybrid Scaffolds of Carbon Nanomaterial and Polymer Nanofibers.

The interconnected porous structures that mimic the extracellular matrix support cell growth in tissue engineering. Nanofibers generated by electrospinning can act as a vehicle for therapeutic cell delivery to a neural lesion. The incorporation of carbon nanomaterials with excellent electrical conductivity in nanofibers is an attractive aspect for design of a nanodevice for neural tissue regeneration. In this study, nanoscaffolds were created by electrospinning poly(ε-caprolactone) (PCL) and three different types of carbon nanomaterials, which are carbon nanotubes, graphene, and fullerene. The component of carbon nanomaterials in nanofibers was confirmed by Fourier transform infrared spectroscopy. The fiber diameter was determined by scanning electron microscopy, and it was found that the diameter varied depending on the type of nanomaterial in the fibers. The incorporation of carbon nanotubes and graphene in the PCL fibers increased the contact angle significantly, while the incorporation of fullerene reduced the contact angle significantly. Incorporation of CNT, fullerene, and graphene in the PCL fibers increased dielectric constant. Astrocytes isolated from neonatal rats were cultured on PCL-nanomaterial nanofibers. The cell viability assay showed that the PCL-nanomaterial nanofibers were not toxic to the cultured astrocytes. The immunolabeling showed the growth and morphology of astrocytes on nanofiber scaffolds. SEM was performed to determine the cell attachment and interaction with the nanoscaffolds. This study indicates that PCL nanofibers containing nanomaterials are biocompatible and could be used for cell and drug delivery into the nervous system.

Recent Advances in Graphene Based TiO2 Nanocomposites (GTiO2Ns) for Photocatalytic Degradation of Synthetic Dyes

Synthetic dyes are widely used in textile, paper, food, cosmetic, and pharmaceutical industries. During industrial processes, some of these dyes are released into the wastewater and their successive release into rivers and lakes produces serious environmental problems. TiO2 is one of the most widely studied and used photocatalysts for environmental remediation. However, it is mainly active under UV-light irradiation due to its band gap of 3.2 eV, while it shows low efficiency under the visible light spectrum. Regarding the exploration of TiO2 activation in the visible light region of the total solar spectrum, the incorporation of carbon nanomaterials, such as graphene, in order to form carbon-TiO2 composites is a promising area. Graphene, in fact, has a large surface area which makes it a good adsorbent for organic pollutants removal through the combination of electrostatic attraction and π-π interaction. Furthermore, it has a high electron mobility and therefore it reduces the electron-hole pair recombination, improving the photocatalytic activity of the semiconductor. In recent years, there was an increasing interest in the preparation of graphene-based TiO2 photocatalysts. The present short review describes the recent advances in TiO2 photocatalyst coupling with graphene materials with the aim of extending the light absorption of TiO2 from UV wavelengths into the visible region, focusing on recent progress in the design and applications in the photocatalytic degradation of synthetic dyes.

Synthesis and applications of carbon nanomaterials for energy generation and storage.

The world is facing an energy crisis due to exponential population growth and limited availability of fossil fuels. Over the last 20 years, carbon, one of the most abundant materials found on earth, and its allotrope forms such as fullerenes, carbon nanotubes and graphene have been proposed as sources of energy generation and storage because of their extraordinary properties and ease of production. Various approaches for the synthesis and incorporation of carbon nanomaterials in organic photovoltaics and supercapacitors have been reviewed and discussed in this work, highlighting their benefits as compared to other materials commonly used in these devices. The use of fullerenes, carbon nanotubes and graphene in organic photovoltaics and supercapacitors is described in detail, explaining how their remarkable properties can enhance the efficiency of solar cells and energy storage in supercapacitors. Fullerenes, carbon nanotubes and graphene have all been included in solar cells with interesting results, although a number of problems are still to be overcome in order to achieve high efficiency and stability. However, the flexibility and the low cost of these materials provide the opportunity for many applications such as wearable and disposable electronics or mobile charging. The application of carbon nanotubes and graphene to supercapacitors is also discussed and reviewed in this work. Carbon nanotubes, in combination with graphene, can create a more porous film with extraordinary capacitive performance, paving the way to many practical applications from mobile phones to electric cars. In conclusion, we show that carbon nanomaterials, developed by inexpensive synthesis and process methods such as printing and roll-to-roll techniques, are ideal for the development of flexible devices for energy generation and storage – the key to the portable electronics of the future.

Enhanced osteogenic differentiation of mesenchymal stem cells on poly(L-lactide) nanofibrous scaffolds containing carbon nanomaterials.

Carbon nanomaterials (CNMs), such as carbon nanotube (CNT) and graphene, are highlighted in bone regeneration because of their osteoinductive properties. Their combinations with nanofibrous polymeric scaffolds, which mimic the morphology of natural extracellular matrix of bone, arouse keen interest in bone tissue engineering. To this end, CNM were incorporated into nanofibrous poly(L-lactic acid) scaffolds by thermal-induced phase separation. The CNM-containing composite nanofibrous scaffolds were biologically evaluated by both in vitro co-culture of bone mesenchymal stem cells (BMSCs) and in vivo implantation. The nanofibrous structure itself demonstrated significant enhancement in cell adhesion, proliferation and oseogenic differentiation of BMSCs, and with the incorporation of CNM, the composite nanofibrous scaffolds further promoted osteogenic differentiation of BMSCs significantly. Between the two CNMs, graphene showed stronger effect in promoting osteogenic differentiation of BMSCs than CNT. The results of in vivo experiments revealed that the composite nanofibrous scaffolds had both good biocompatibility and strong ability in inducing osteogenesis. CNMs could remarkably enhance the expression of osteogenesis-related proteins as well as the formation of type I collagen. Similarly, the graphene-containing composite nanofibrous scaffolds demonstrated the strongest effect on inducing osteogenesis in vivo. These findings demonstrated that CNM-containing composite nanofibrous scaffolds were obviously more efficient in promoting osteogenesis than pure polymeric scaffolds.

Health monitoring of structural composites with embedded carbon nanotube coated glass fiber sensors

Structural health monitoring (SHM) seeks to provide ongoing monitoring of a structure’s integrity. Current SHM approaches include embedding some type of sensor within the composite or applying a sensor to the outside surface of the structure. These sensors react to strain or other changes in order to detect damage. In this study, a novel, multi-modal, nanomaterial based sensor technology that can provide wide area detection of damage was used. The efforts presented here serve as a feasibility study into the incorporation of carbon nanomaterials into structural composites as sensors. The carbon nanotube (CNT) covered fiber (fuzzy fiber) sensors exhibit similar sensitivity to conventional strain gages and are more easily integrated into composite structures as the sensor itself is a composite. The fuzzy fiber strain gages can be used to sense strain within composite structures and can be readily integrated into the structural laminate to provide sensing over large sections and in previously inaccessible locations. The unique properties of the fuzzy fiber lends itself to application in a wide range of sensing tasks within a structural composite including strain, temperature, degradation, etc. The fuzzy fiber may be tailored so that the same basic sensor can be used for a multitude of sensing applications.

A Natural Vanishing Act: The Enzyme-Catalyzed Degradation of Carbon Nanomaterials

Over the past three decades, revolutionary research in nanotechnology by the scientific, medical, and engineering communities has yielded a treasure trove of discoveries with diverse applications that promise to benefit humanity. With their unique electronic and mechanical properties, carbon nanomaterials (CNMs) represent a prime example of the promise of nanotechnology with applications in areas that include electronics, fuel cells, composites, and nanomedicine. Because of toxicological issues associated with CNMs, however, their full commercial potential may not be achieved. The ex vitro, in vitro, and in vivo data presented in this Account provide fundamental insights into the biopersistence of CNMs, such as carbon nanotubes and graphene, and their oxidation/biodegradation processes as catalyzed by peroxidase enzymes. We also communicate our current understanding of the mechanism for the enzymatic oxidation and biodegradation. Finally, we outline potential future directions that could enhance our mechanistic understanding of the CNM oxidation and biodegradation and could yield benefits in terms of human health and environmental safety. The conclusions presented in this Account may catalyze a rational rethinking of CNM incorporation in diverse applications. For example, armed with an understanding of how and why CNMs undergo enzyme-catalyzed oxidation and biodegradation, researchers can tailor the structure of CNMs to either promote or inhibit these processes. In nanomedical applications such as drug delivery, the incorporation of carboxylate functional groups could facilitate biodegradation of the nanomaterial after delivery of the cargo. On the other hand, in the construction of aircraft, a CNM composite should be stable to oxidizing conditions in the environment. Therefore, pristine, inert CNMs would be ideal for this application. Finally, the incorporation of CNMs with defect sites in consumer goods could provide a facile mechanism that promotes the degradation of these materials once these products reach landfills.

Effects of functionalized fullerenes on bifenthrin and tribufos toxicity to Daphnia magna: Survival, reproduction, and growth rate

Incorporation of carbon nanomaterials into industrial and consumer products is increasing, yet their impact on aquatic ecosystems alone and in chemical mixtures is largely unknown. Carbon nanomaterials may be found in the aquatic environment as mixtures with pesticides because of their proposed use in agriculture as smart delivery systems and nanosensors. The interaction effects of a functionalized fullerene ([1,2-methanofullerene C₆₀]-61-carboxylic acid) (fC₆₀) at 52.8 µg/L and the hydrophobic pesticides bifenthrin and tribufos were examined. The test organism was Daphnia magna, and response variables included 48-h survival, reproduction (bifenthrin, 70-d; tribufos, 21-d), and 10-d growth. Both pesticides reduced D. magna survival and reproduction (p < 0.05). Fullerenes significantly increased bifenthrin acute toxicity but did not significantly affect chronic endpoints or growth (p > 0.05). Median lethal concentrations (LC50s), median inhibition concentrations (IC50s) for days surviving, and IC50s for reproduction were 0.86, 0.55, and 0.49 µg/L for bifenthrin; 0.22, 0.39, and 0.77 µg/L for fC₆₀-bifenthrin mix; 6.63, 9.89, and 5.79 µg/L for tribufos; and 9.17, 8.17, and 6.59 µg/L for fC₆₀-tribufos mix. Mixtures did not affect instantaneous growth rate (p > 0.05). These results suggest that fC₆₀ had little effect on pesticide chronic toxicity but influenced acute toxicity. Given the widespread application of nanotechnology, the influence of nanomaterials on environmental contaminants is an important consideration. Thus, our results may be useful in the development and use of nanotechnology in agricultural practices.