Various applications of carbon nanotubes require their chemical modification in order to tune/con... more Various applications of carbon nanotubes require their chemical modification in order to tune/control their physicochemical properties. One way for achieving this control is by carrying out doping processes through which atoms and molecules interact (covalently or noncovalently) with the nanotube surfaces. The aim of this chapter is to emphasize the importance of different types of doping in carbon nanotubes (single-, double- and multiwall). There are three main categories of doping: exohedral, endohedral and inplane doping. We will review the most efficient ways to dope carbon nanotubes and discuss the effects on the electronic, vibrational, chemical, magnetic and mechanical properties. In addition, we will discuss the different ways of characterizing these doped nanotubes using spectroscopic techniques, such as resonant Raman, X-ray photoelectron, electron energy loss spectroscopy and others. It will be demonstrated that doped carbon nanotubes could be used in the fabrication of nanodevices (e.g., sensors, protein immobilizers, field emission sources, efficient composite fillers, etc.). We will also present results related to the importance of inplane-doped nanotubes for attaching various metal clusters and polymers covalently using wet chemical routes.
This paper presents a microwave characterization of several carbon-based composite materials inte... more This paper presents a microwave characterization of several carbon-based composite materials interesting the future aircraft/aerospace systems. They consist in epoxy resin reinforced with five different carbon species: micro-sized granular graphite, fullerenes, carbon nanofibers, single- and multi-walled carbon nanotubes. Main goal of this work is to show how carbon inclusions size and geometry are able to significantly modify the electromagnetic properties
Magnetic multiwalled carbon nanotube (MWCNTs) nanocomposites have been created by the assembly of... more Magnetic multiwalled carbon nanotube (MWCNTs) nanocomposites have been created by the assembly of Mg-Ni-Ti substituted barium ferrite nanoparticles onto surface of MWCNTs. X-ray diffraction (XRD) and transmission electron microscope (TEM) were used to demonstrate the successful attachment of ferrite nanoparticles to MWCNTs. Vibrating sample magnetometer (VSM) confirms the relatively strong dependence of saturation of magnetization and coercivity with the volume percentage of MWCNTs. Reflection loss evaluations indicated that the nanocomposites display a great potential application as wide-band electromagnetic wave absorbers.
In this research work, magnetic multi-walled carbon nanotube (MWCNT) nanocomposites have been cre... more In this research work, magnetic multi-walled carbon nanotube (MWCNT) nanocomposites have been created by the assembly of Zn–Sn substituted strontium ferrite film onto the surface of MWCNTs. X-ray diffraction and transmission electron microscopy were used to demonstrate the successful attachment of ferrite films to MWCNTs. Mössbauer spectroscopy indicates that the Zn–Sn ions preferentially occupy the 2b and 4f2 sites. Vibrating sample magnetometry confirms the relatively strong dependence of saturation magnetization with the volume percentage of MWCNTs. Microwave absorption of the MWCNTs/doped strontium ferrite nanocomposites is evidently enhanced compared to that of pure MWCNTs and ferrite. The maximum reflection loss increased significantly with an increase in volume percentage of MWCNTs in nanocomposites. Reflection loss evaluations indicated that the nanocomposites display a great potential application as wide-band electromagnetic wave absorbers.► Feasibility of novel modified sol–gel way for coating nanometer scale substituted strontium ferrite on entity carbon nanotube. ► Microwave absorption of MWCNTs/doped strontium ferrite nanocomposite is clearly better compared to that of pure MWCNTs and ferrite. ► Reflection loss estimate indicates the nanocomposite shows great latent application as wide-band electromagnetic wave absorbers.
Homogeneous carbon nanotube/polymer composites were fabricated using noncovalently functionalized... more Homogeneous carbon nanotube/polymer composites were fabricated using noncovalently functionalized, soluble single-walled carbon nanotubes (SWNTs). These composites showed dramatic improvements in the electrical conductivity with very low percolation threshold ( ...
Materials Science and Engineering B-advanced Functional Solid-state Materials, 2008
The preparation and characterization of CNTs/polymer (PET, PP, PE and varnish) composites were st... more The preparation and characterization of CNTs/polymer (PET, PP, PE and varnish) composites were studied for microwave absorption applications in the range of 2–18 GHz. The results indicated the position of reflectivity peak moves to a lower frequency and the loss factors of composites increase with increasing CNTs concentrations. When CNTs concentration was above 4 wt%, there was a sharp increase of loss tangent. 4 wt% CNTs/PET and 8 wt% CNTs/varnish composites had considerable absorbing peak at 7.6 GHz, 15.3 GHz and achieved maximum absorbing value of 17.61 dB, 24.27 dB, respectively. In addition, the frequencies range for absorbing values exceeding 5 dB of CNTs/(PET, PP, varnish) composites are 13 GHz, 10 GHz and 6 GHz, respectively. The microwave absorption of CNTs composites can be mainly attributed to the dielectric loss rather than magnetic loss.
High-density attachment and one-dimensional (1D) array of FePt nanoparticles (NPs) along carbon n... more High-density attachment and one-dimensional (1D) array of FePt nanoparticles (NPs) along carbon nanotubes (CNTs) surface to generate FePt/CNT nanocomposites were successfully obtained via a facile CNT-mediated microwave polyol method. The as-prepared 1D FePt/CNTs is about 10–20 nm in diameter and up to μm scale in length. By adjusting the solvents, the ratio of Fe/Pt and the attached density of FePt NPs on the surface of CNTs could be well controlled. The structures, composition, and magnetic properties of the FePt/CNTs were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and magnetic measurements. The possible growth mechanism has also been proposed.
... Nanocomposites of carbon nanotubes (CNTs) and magnetic metallic materials have attracted exte... more ... Nanocomposites of carbon nanotubes (CNTs) and magnetic metallic materials have attracted extensive interest ... In this letter, a uniformly mixed nanocomposite was fabricated in large scale by a ... where and are the relative permeability and permittivity of the composite medium, is ...
Various applications of carbon nanotubes require their chemical modification in order to tune/con... more Various applications of carbon nanotubes require their chemical modification in order to tune/control their physicochemical properties. One way for achieving this control is by carrying out doping processes through which atoms and molecules interact (covalently or noncovalently) with the nanotube surfaces. The aim of this chapter is to emphasize the importance of different types of doping in carbon nanotubes (single-, double- and multiwall). There are three main categories of doping: exohedral, endohedral and inplane doping. We will review the most efficient ways to dope carbon nanotubes and discuss the effects on the electronic, vibrational, chemical, magnetic and mechanical properties. In addition, we will discuss the different ways of characterizing these doped nanotubes using spectroscopic techniques, such as resonant Raman, X-ray photoelectron, electron energy loss spectroscopy and others. It will be demonstrated that doped carbon nanotubes could be used in the fabrication of nanodevices (e.g., sensors, protein immobilizers, field emission sources, efficient composite fillers, etc.). We will also present results related to the importance of inplane-doped nanotubes for attaching various metal clusters and polymers covalently using wet chemical routes.
This paper presents a microwave characterization of several carbon-based composite materials inte... more This paper presents a microwave characterization of several carbon-based composite materials interesting the future aircraft/aerospace systems. They consist in epoxy resin reinforced with five different carbon species: micro-sized granular graphite, fullerenes, carbon nanofibers, single- and multi-walled carbon nanotubes. Main goal of this work is to show how carbon inclusions size and geometry are able to significantly modify the electromagnetic properties
Magnetic multiwalled carbon nanotube (MWCNTs) nanocomposites have been created by the assembly of... more Magnetic multiwalled carbon nanotube (MWCNTs) nanocomposites have been created by the assembly of Mg-Ni-Ti substituted barium ferrite nanoparticles onto surface of MWCNTs. X-ray diffraction (XRD) and transmission electron microscope (TEM) were used to demonstrate the successful attachment of ferrite nanoparticles to MWCNTs. Vibrating sample magnetometer (VSM) confirms the relatively strong dependence of saturation of magnetization and coercivity with the volume percentage of MWCNTs. Reflection loss evaluations indicated that the nanocomposites display a great potential application as wide-band electromagnetic wave absorbers.
In this research work, magnetic multi-walled carbon nanotube (MWCNT) nanocomposites have been cre... more In this research work, magnetic multi-walled carbon nanotube (MWCNT) nanocomposites have been created by the assembly of Zn–Sn substituted strontium ferrite film onto the surface of MWCNTs. X-ray diffraction and transmission electron microscopy were used to demonstrate the successful attachment of ferrite films to MWCNTs. Mössbauer spectroscopy indicates that the Zn–Sn ions preferentially occupy the 2b and 4f2 sites. Vibrating sample magnetometry confirms the relatively strong dependence of saturation magnetization with the volume percentage of MWCNTs. Microwave absorption of the MWCNTs/doped strontium ferrite nanocomposites is evidently enhanced compared to that of pure MWCNTs and ferrite. The maximum reflection loss increased significantly with an increase in volume percentage of MWCNTs in nanocomposites. Reflection loss evaluations indicated that the nanocomposites display a great potential application as wide-band electromagnetic wave absorbers.► Feasibility of novel modified sol–gel way for coating nanometer scale substituted strontium ferrite on entity carbon nanotube. ► Microwave absorption of MWCNTs/doped strontium ferrite nanocomposite is clearly better compared to that of pure MWCNTs and ferrite. ► Reflection loss estimate indicates the nanocomposite shows great latent application as wide-band electromagnetic wave absorbers.
Homogeneous carbon nanotube/polymer composites were fabricated using noncovalently functionalized... more Homogeneous carbon nanotube/polymer composites were fabricated using noncovalently functionalized, soluble single-walled carbon nanotubes (SWNTs). These composites showed dramatic improvements in the electrical conductivity with very low percolation threshold ( ...
Materials Science and Engineering B-advanced Functional Solid-state Materials, 2008
The preparation and characterization of CNTs/polymer (PET, PP, PE and varnish) composites were st... more The preparation and characterization of CNTs/polymer (PET, PP, PE and varnish) composites were studied for microwave absorption applications in the range of 2–18 GHz. The results indicated the position of reflectivity peak moves to a lower frequency and the loss factors of composites increase with increasing CNTs concentrations. When CNTs concentration was above 4 wt%, there was a sharp increase of loss tangent. 4 wt% CNTs/PET and 8 wt% CNTs/varnish composites had considerable absorbing peak at 7.6 GHz, 15.3 GHz and achieved maximum absorbing value of 17.61 dB, 24.27 dB, respectively. In addition, the frequencies range for absorbing values exceeding 5 dB of CNTs/(PET, PP, varnish) composites are 13 GHz, 10 GHz and 6 GHz, respectively. The microwave absorption of CNTs composites can be mainly attributed to the dielectric loss rather than magnetic loss.
High-density attachment and one-dimensional (1D) array of FePt nanoparticles (NPs) along carbon n... more High-density attachment and one-dimensional (1D) array of FePt nanoparticles (NPs) along carbon nanotubes (CNTs) surface to generate FePt/CNT nanocomposites were successfully obtained via a facile CNT-mediated microwave polyol method. The as-prepared 1D FePt/CNTs is about 10–20 nm in diameter and up to μm scale in length. By adjusting the solvents, the ratio of Fe/Pt and the attached density of FePt NPs on the surface of CNTs could be well controlled. The structures, composition, and magnetic properties of the FePt/CNTs were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and magnetic measurements. The possible growth mechanism has also been proposed.
... Nanocomposites of carbon nanotubes (CNTs) and magnetic metallic materials have attracted exte... more ... Nanocomposites of carbon nanotubes (CNTs) and magnetic metallic materials have attracted extensive interest ... In this letter, a uniformly mixed nanocomposite was fabricated in large scale by a ... where and are the relative permeability and permittivity of the composite medium, is ...
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