Adsorption Of Multi-walled Carbon Nanotubes Research Articles

Durable Large-Area Thin Films of Graphene/Carbon Nanotube Double Layers as a Transparent Electrode

We prepared durable, uniform, large-area ultrathin transparent films composed of double layers of reduced graphene oxide (RG-O) and multiwalled carbon nanotubes (MWNTs) via a self-assembly process. The adsorption of MWNTs onto RG-O films considerably decreased the sheet resistance of the films without compromising much on transparency. This self-assembly approach could be used to fabricate transparent electronic devices without post-transfer processes on a large scale.

Synthesis, characterization, and photocatalytic analysis of CNT/TiO 2 composites derived from MWCNTs and titanium sources

CNT/TiO 2 composites were prepared using multi-walled carbon nanotubes (MWCNTs) as a starting material, and titanium(IV) isopropoxide, titanium(IV) propoxide and titanium(IV) n-butoxide as titanium sources and benzene as a solvent. The composites were characterized by N 2 adsorption, scanning electron microscopy, X-ray diffraction, energy dispersive X-ray analysis, and UV-vis absorption spectroscopy. The photoactivity of the prepared materials was evaluated by the conversion of methylene blue (MB, C 16H 18N 3S·Cl·3H 2O) in aqueous solution under UV irradiation. It can be found that the MB removal effect of the CNT/TiO 2 composites is not only due to the adsorption of MWCNTs and the photocatalytic degradation of TiO 2 but also to electron transfer between MWCNTs and TiO 2.

Electrically Conductive Polymeric Nanocomposites Prepared in Alcohol Dispersion of Multiwalled Carbon Nanotubes

In this study, electrically conductive microspheres were prepared by the adsorption of multiwalled carbon nanotubes (MWCNTs) on the surfaces of polymeric microspheres (polystyrene and poly(methylmethacrylate)) in MWCNT-dispersed alcohols (methanol, ethanol, and isopropanol) without surfactants. The stability of the MWCNT dispersions was measured using a recently developed multiple light scattering measurement instrument (Turbiscan). The individual MWCNTs on the surfaces of the microspheres were observed by scanning electron microscopy. The contents of MWCNTs in the composites were determined by thermogravimetric analysis and were found to range from 1.6 wt% to 4.5 wt%. The electrical conductivity and surface charge of the composite microspheres were also investigated.

Immobilization of acetylcholinesterase based on the controllable adsorption of carbon nanotubes onto an alkanethiol monolayer for carbaryl sensing

A simple method to immobilize acetylcholinesterase (AChE) on the controllable adsorption of multiwalled carbon nanotubes (MWCNTs) onto an alkanethiol self-assembled monolayer (C(6)H(13)SH SAM) modified Au electrode was proposed. The surface coverage of the MWCNTs was readily controlled by adjusting the immersion time for the adsorption of the MWCNTs. Atomic force microscopy (AFM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to monitor these controllable fabrication processes. The MWCNTs adsorbed onto the SAM surface substantially restores the heterogeneous electron transfer between the bare Au electrode and the redox system in the solution phase that is almost totally blocked by the SAM of C(6)H(13)SH, and as a result, the prepared MWCNT-SAM-modified electrode possesses good electrode reactivity without a remarkable barrier to heterogeneous electron transfer. Due to the inherent conductive properties of MWCNTs, the immobilized AChE exhibited high affinity to its substrate and produced a detectable and fast response. Thus, a sensitive, efficient and stable amperometric sensor for quantitative determination of carbaryl was developed. The inhibition of carbaryl was proportional to its concentration ranging from 0.001 to 1 microg mL(-1) and 2 to 15 microg mL(-1), with a detection limit of 0.6 ng mL(-1). The determination of carbaryl in garlic samples showed acceptable accuracy, which provided a new promising tool for analysis of enzyme inhibitors.

Real-time observation of electrorheological fluids using synchrotron X-ray imaging

Experiments performed using the novel technique of real-time microradiography with coherent X-rays provided clear experimental evidence of the “fibrilization” phenomenon of electrical conductive microspheres between a copper microelectrode (anode) and platinum plate (cathode) in electrorheological fluids under an applied voltage (about 2kV/mm). The surface-conductive polymeric microspheres were prepared by the adsorption of multi-walled carbon nanotubes (MWCNTs) on the surface of poly(methylmethacrylate) microspheres (6.5μm). We also observed the process of MWCNT adsorption on the polymeric microspheres in the MWCNT dispersion containing surfactants and the assembly of MWCNTs-coated microspheres during their sedimentation in real-time by microradiography.

Electrically Conducting Silk Fibroin Microspheres by Incorporation of Multiwalled Carbon Nanotubes on their Surfaces

Electrorheological (ER) particles were obtained by the adsorption of multiwalled carbon nanotubes (MWCNT) on the surface of silk fibroin microspheres. The resulting spherical polymeric microspheres consist of a silk fibroin core and an MWCNT shell, which is electrically conducting. The silk fibroin microspheres were prepared by the phase separation of the silk fibroin and poly(ethylene oxide) (PEO) blend solution, and the MWCNT dispersion was prepared by ultrasonication with cetyltrimethylammonium bromide (CTAB) surfactant. The ER particles were prepared using a simple process involving the blending of the silk fibroin microsphere suspension and aqueous MWCNT dispersion. The morphology of the ER particles was examined by field emission scanning electron microscopy (FESEM) and their electrical conductivity measured by the four-probe method was 4.8×10-4 S/cm. The prepared composite microspheres suspended in silicone oil showed typical ER characteristics, including the formation of a chain-like structure under an applied electric field (1.9 kV/mm). This phenomenon can be explained by the interfacial polarizability of the MWCNTs adsorbed on the surface of the polymeric microspheres.

Electrically Conducting Polymeric Microspheres Prepared by Adsorption of Multiwalled Carbon Nanotubes

Multiwalled carbon nanotubes (MWCNTs) were incorporated onto the surface of polystyrene (PS) microspheres by a simple and potentially scalable process. PS microspheres, 3.0 μm in diameter, were prepared using a dispersion polymerization method. These were adopted as the suspended particles for electrorheological (ER) fluids, in which the electrical conductivity was mainly derived from the conducting MWCNTs layers coated on the surface of the microspheres. The MWCNT/PS composite suspensions in silicone oil showed the typical characteristics of an ER fluid, forming a chain-like structure under an applied electric field (0.8 kV/mm). The MWCNTs/PS composite microspheres exhibited a conductivity of about 2.0 × 10−4 S/cm, which is in the typical range for ER fluids. This phenomenon can be explained by the interfacial polarizability of the MWCNTs adsorbed on the surface of the polymeric microspheres.

The effect of pretreatments on hydrogen adsorption of multi-walled carbon nanotubes

Hydrogen adsorption of multi-walled carbon nanotubes (MWNTs) was investigated under moderate pressure (12MPa) at room temperature. The effects of annealing and doping on the hydrogen adsorption of carbon nanotubes have been discussed. It is showed that both heat-treatment and doping play an important role in the hydrogen adsorption of carbon nanotubes. Even when doped with the same element, the hydrogen uptake property was greatly different when the concentration of the doping solution changed. An optimal result (3.2wt.%) was achieved for carbon nanotubes annealed in N2 at 500°C and soaked in 1.0M KNO3 solution.