A Facile Method for Creating an Array of Metal-Filled Carbon Nanotubes (original) (raw)
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Bulletin of Materials Science, 2013
Electrically conducting nanocomposites of polyaniline (PANI) with carbon-based fillers have evinced considerable interest for various applications such as rechargeable batteries, microelectronics, sensors, electrochromic displays and light-emitting and photovoltaic devices. The nature of both the carbon filler and the dopant acid can significantly influence the conductivity of these nanocomposites. This paper describes the effects of carbon fillers like carbon black (CB), graphite (GR) and muti-walled carbon nanotubes (MWCNT) and of dopant acids like methane sulfonic acid (MSA), camphor sulfonic acid (CSA), hydrochloric acid (HCl) and sulfuric acid (H 2 SO 4) on the electrical conductivity of PANI. The morphological, structural and electrical properties of neat PANI and carbon-PANI nanocomposites were studied using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), UV-Vis spectroscopy and the four-point probe technique, respectively. Thermogravimetric analysis (TGA) and X-ray diffraction (XRD) studies were also conducted for different PANI composites. The results show that PANI and carbon-PANI composites with organic acid dopants show good thermal stability and higher electrical conductivity than those with inorganic acid dopants. Also, carbon-PANI composites generally show higher electrical conductivity than neat PANI, with highest conductivities for PANI-CNT composites. Thus, in essence, PANI-CNT composites prepared using organic acid dopants are most suitable for conducting applications.
Effect of annealing on electrical conductivity and morphology of polyaniline films
Journal of Applied Polymer Science, 2001
We report structure–property relationships of polyaniline emeraldine base (EB) films that were produced by combining different processing steps in various sequences. The effect of annealing and doping processes on the surface structure of the films was investigated by atomic force microscopy (AFM), and the corresponding changes to the chemical structure of the EB films were monitored by Fourier transform infrared spectroscopy. AFM results indicate that after doping polyaniline (EB) films with HCl, the root mean square (rms) roughness of the surface of EB film increased ∼ 46%. When the doped films were annealed at 180°C under a nitrogen atmosphere for 3 h, the rms roughness was essentially unchanged from that of the initial, undoped films. The electrical conductivity of the films also showed a significant dependence on the processing sequence. When the doped polyaniline (EB) films were annealed, no electrical conductivity was observed. When these films were redoped, only ∼ 6% of the initial conductivity could be recovered. In another processing sequence in which the polyaniline (EB) films were first annealed and then doped, the electrical conductivity was only ∼ 12% relative to the film that was doped immediately after being cast. From this work, a strategy to reduce the surface roughness of films made from electrically conducting polyaniline (EB) is proposed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3602–3610, 2001
Preparation of polyaniline/multiwalled carbon nanotube composite by novel electrophoretic route
Carbon, 2008
A nano-structured composite film comprising of emeraldine salt (ES) and carboxyl group functionalized multiwalled carbon nanotubes (MWCNT-c) has been electrophoretically prepared from their colloidal suspension on an indium-tin-oxide (ITO) coated glass plate. This nano-structured composite film (ES/MWCNT-c) has been characterized using atomic force microscopy (AFM), ultraviolet-visible (UV-visible) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The AFM studies reveal porous morphology with uniformly distributed MWCNT-c in this composite film. The SEM and TEM investigations reveal wrapping of MWCNT-c with the chains of ES. UV-visible and FT-IR investigations show the formation of MWCNT-c doped composite at the molecular level. The results of the CV and EIS studies indicate enhanced electrochemical and charge transfer behavior of the composite. The application of ES/ MWCNT-c/ITO electrode to biosensor for cholesterol indicates short response time (10 s) and high sensitivity (6800 nA mM À1 ).
2018
Conducting polyaniline (PANI) in nano dimension was prepared in presence of aqueous hydrochloric acid (HCl) or toluene sulfonic acid (TSA) as doping agents and ammonium persulfate (APS) as oxidizing agent. Composites of the PANI and multi walled carbon nanotubes (MWCNT) were prepared by in situ polymerization technique at room temperature. The structural composition, morphology, thermal decomposition behavior and conductivity of PANI and the composites were investigated. Studies include Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD) pattern, uvvisible spectroscopy and thermogravimetric analysis (TGA). The electrical conductivity of the PANI-MWCNT composites as well as the pure PANI was measured by conventional four-probe method. The electrical conductivities of the two PANIs show that nano PANI-TSA has a higher conductivity (0.824 S/cm -1 ) compared to PANI-HCl (0.478 S/cm -1 ). PANI...
Electrochemical Properties of the Composites Synthesized from Polyaniline and Modified MWCNT
Chemistry & Chemical Technology
Electroactive composites made of polyaniline and MWCNT modified by aminobenzene groups were electrochemically synthesized. SEM observation confirms that the composites become more porous as the MWCNT aggregation on the electrode surface gradually increases. Paraboloid dependence of specific electrical conductivity on the MWCNT content was found for the composites with more than 2.0 wt % of MWCNT. Obtained results confirmed a strong relationship between the surface and electrical properties allowing to offer their optimization using different amount of MWCNTs and preparation procedure.
Synthesis and characterization of polyaniline prepared with the dopant mixture of (ZrO2/PbI2)
Journal of Physics D: Applied …, 2009
Polyaniline-carboxylic acid functionalized multi-walled carbon nanotube (PAni/c-MWNT) nanocomposites were prepared in sodium dodecyl sulfate (SDS) emulsion. First, the c-MWNTs were dispersed in SDS emulsion then the aniline was polymerized by the addition of ammonium persulfate in the absence of any added acid. SDS forms the functionalized counterion in the resulting nanocomposites. The content of c-MWNTs in the nanocomposites varied from 0 to 20 wt%. A uniform coating of PAni was observed on the c-MWNTs by field-emission scanning electron microscopy (FESEM). The PAni/c-MWNT nanocomposites have been characterized by different spectroscopic methods such as UV-Visible, FT-Raman, and FT-IR. The UV-Visible spectra of the PAni/c-MWNT nanocomposites exhibited an additional band at around 460 nm, which implies the induced doping of the MWNTs by the carboxyl group. The FT-IR spectra of the PAni/c-MWNT nanocomposites showed an inverse intensity ratio of the bands at 1562 and 1480 cm S1 as compared to that of pure PAni, which reveals that the PAni in the nanocomposites is richer in quinoid units than the pure PAni. The increase in the thermal stability of conductivity of the nanocomposites was due to the network structure of nanotubes and the charge transfer between the quinoid rings of the PAni and the c-MWNTs.
Synthesis and characterization of new polyaniline/nanotube composites
Materials Science and Engineering: C, 2003
New polyaniline/nanotube (PANI/NT) composites have been synthesized by ''in situ'' polymerization processes using both multi-wall carbon nanotubes (MWNTs) and single-wall carbon nanotubes (SWNTs) in concentrations ranging from 2 to 50 wt.%. Although no structural changes are observed using MWNTs above a concentration of 20 wt.%, the in situ synthesis results in electronic interactions between nanotubes and the quinoid ring of PANI leading to enhanced electronic properties and thus to the formation of a genuine PANI/MWNT composite material. On the other hand, using SWNTs favors the formation of inhomogeneous mixtures rather than of a homogeneous composite materials, independent of the SWNT concentration. X-ray diffraction, Raman and transport measurements show the different behavior of both classes of nanotubes in PANI/NT materials. The difficulties in the formation of a true PANI/SWNT composite are related to the far more complex structure of the SWNT material itself, i.e. to the presence of entangled bundles of SWNTs, amorphous carbon and even catalytic metal particles. D