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Cu-nanoparticles were coated on the sidewall of multiwalled carbon nanotubes (MWCNTs) by a facile and effective in situ approach via the template of a polyelectrolyte (polyethylenimine or poly(sodium 4-styrene sulfonate)) noncovalently functionalized on MWCNTs. Extensive characterizations of the fabricated nanocomposites have been studied using X-ray diffraction, transmission electron microscopy, selected area electron diffraction, X-ray photoelectron spectroscopy, thermal gravimetric analysis and inductively coupled plasma. The results demonstrate that Cu-nanoparticles were well distributed on the surface of MWCNTs. The nanocomposites can be easily modified on the glassy carbon electrodes due to the presence of polyelectrolyte. The electrocatalytic activity of the modified electrodes towards glucose oxidation was investigated by cyclic voltammetry and chronoamperometry. The nanocomposites showed good non-enzymatic electrocatalytic responses to glucose in alkaline media, and can be used for the development of enzyme-free glucose sensors.

Multiwalled carbon nanotube (MWCNT)/polystyrene (PS) or poly(methyl methacrylate) (PMMA) composites were successfully prepared by in situ emulsion polymerization under microwave irradiation using potassium persulfate as initiator. Then the composites were treated with tetrahydrofuran (THF) to remove the free polymers. The resultant PS or PMMA-wrapped MWCNT samples, which were soluble in common organic solvents such as 1,2-dichlorobenzene, THF, chloroform and others, have been well-characterized by TEM, thermal gravimetric analyses, FT-IR, UV–vis and Raman spectra. The optical limiting properties of the polymer-wrapped MWCNT samples were investigated by open-aperture z-scan method. All of the polymer modified MWCNT samples in chloroform showed much better optical limiting behavior than pristine MWCNT in chloroform.

A series of bromo-terminated four-armed homopolymers [polystyrene (PSt) and poly(methyl methacrylate) (PMMA)], prepared by atom transfer radical polymerization (ATRP), were subsequently functionalized with fullerene C60 by atom transfer radical addition (ATRA) reaction using CuBr/2,2′-bipyridine (bipy) as the catalyst system. The C60 end-capped four-armed polymer derivatives were then characterized by gel permeation chromatography (GPC), UV–vis, FT-IR, thermal gravimetric analyses (TGA) and differential scanning calorimeter (DSC). Another technique of synthesizing C60-functionalized four-armed polymers from azide functional polymers was also applied for comparison. The optical limiting behavior of C60 end-capped four-armed polymers prepared via ATRA reaction were measured in THF solution at 532 nm. Both groups of fullerene-functionalized polymers (C60-PSts and C60-PMMAs) are provided with optical limiting properties.

Multi-walled carbon nanotubes (MWCNTs) were coated with rare-earth (RE) (Eu(3+), Tb(3+)) complex layers by a simple in situ synthetic method via noncovalently functionalized MWCNTs with sodium dodecyl sulfate. Extensive characterizations of the resulting nanocomposite materials have been performed using scanning electron microscopy (SEM), FT-IR spectra, x-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive x-ray spectroscopy (EDS) and x-ray photoelectron spectroscopy (XPS). The photoluminescence properties of the RE-complex-modified MWCNTs were also investigated. Under the excitation of UV light, these samples exhibit characteristic emissions of Eu(3+) or Tb(3+) ions. The presence of the MWCNT framework does not quench the lanthanide-centered luminescence originating from the characteristic electronic transitions within the 4f shell of the RE ions. Furthermore, the existence of the nanotube framework can improve the stability of the RE complex under UV irradiation and elongate the fluorescence lifetime of the RE complex.

A metal sulfide such as ZnS, CdS, Ag(2)S or PbS was coated on the sidewall of multiwalled carbon nanotubes (MWCNTs) by an in situ wet chemical synthesis approach via noncovalent functionalization of MWCNTs with a polyelectrolyte (polyethylenimine or poly(diallyldimethylammonium chloride)) without causing significant electronic and structural modification of the carbon nanotubes. Extensive characterizations of the fabricated nanocomposites have been performed using x-ray diffraction, transmission electron microscopy (TEM), high resolution TEM, energy dispersive x-ray spectroscopy, selected area electron diffraction, thermal gravimetric analysis, Fourier transform IR spectra, UV-vis spectra and x-ray photoelectron spectroscopy. The coating layers were composed of metal sulfide nanoparticles with a mean size of less than 10 nm. The optical limiting property measurements for some metal sulfide coated MWCNTs were carried out by the open-aperture z-scan technique. The results demonstrate that the samples suspended in water showed optical limiting behavior better than that of purified MWCNTs.