The sidewalls of multiwalled carbon nanotubes (MWCNTs) were decorated with CdS nanoparticles using a mild two-step approach, with in situ polymerized thiophene (PTh) acting as an interlinker. Extensive characterization of the materials has been carried out using transmission electron microscopy, selected area electron diffraction, X-ray diffraction, thermal gravimetric analysis, ultraviolet-visible absorption spectroscopy and photoluminescence spectroscopy. Optical limiting (OL) studies have been performed using the open Z-scan technique at the laser wavelengths of 532 and 1064 nm. The MWCNT-PTh-CdS system shows an enhanced OL effect in comparison to the pristine MWCNTs, particularly at 1064nm. Possible underlying mechanisms are proposed based on the results of nonlinear scattering measurements.

We report the synthesis and characterization of multiwalled carbon nanotube (MWCNT)– organically modified silicate (ORMOSIL) nanohybrid gel glass, in which the incorporated MWCNTs are covalently bonded to the silica network. The structural properties of the 3-aminopropyltriethoxysilane functionalized MWCNTs and MWCNT–ORMOSIL nanohybrid gel glass are comprehensively characterized using spectroscopic and electron microscopy techniques. We find that the agglomeration of incorporated MWCNTs is effectively restrained and that the MWCNTs are dispersed homogeneously and individually in the gel glass matrix. Compared with the mother MWCNT suspension, the resultant nanohybrid gel glasses demonstrate sustained nonlinear optical properties at both 532 and 1064 nm laser wavelengths.

The fabrication of nanocomposites by covalent inclusion of inorganic nanoparticles in an organic polymer matrix is highly topical and may find applications in the electronics, optics and energy sectors. Incorporation of CdS nanoparticles into the polyacrylonitrile (PAN) matrices could be expected to display improved or enhanced optoelectronic and optical properties. Using a newly synthesized RAFT agent, i.e., CdS-DDAT nanoparticles (DDAT: S-1-Dodecyl-S0-(a, a0-dimethyl-a00-acetic acid) trithiocarbonate), CdS covalently functionalized polyacrylonitrile (CdS-PAN) nanocomposite material was prepared in the presence of small amount of AIBN under ultrasonic radiation. This material, which exhibits an induced positive nonlinear absorption of incident light, has been well-characterized by a variety of physical techniques such as GPC, UV/vis, FT-IR, TGA, XRD and Z-scan.

Multi-walled carbon nanotubes (MWNTs) doped silica gel glass matrix nano-composites were successfully prepared by sol-gel technique. Morphology of the composites was characterized by scanning electrical microscope and transmittance electrical microscope images. Pore structure of net MWNTs, silica gel glass matrix and resulted MWNTs doped composites were studied and compared. The results show that MWNTs are well dispersed in the gel glass matrix and sol-gel processing does not appear to affect the morphology of MWNTs. Pore structure of the silica matrix is changed by the introduction of MWNTs.

A series of dimethyl-modified silica xerogels with different dimethyl contents were prepared by one-step hydrolysis and co-condensation from tetraethyloxysilane (TEOS) and dimethyldiethoxysilane (DEOS) containing precursor. The structural and textural evolution was traced by FT-IR spectroscopy, nitrogen absorption, scanning electron microscopy (SEM), transmittance electrical microscope (TEM), UV-Vis spectroscopy and thermogravimetric analysis (TGA). The addition of dimethyl groups can greatly reduce the pore size distribution of the resulted sample, while the 30% DEOS–70% TEOS sample is the most textural compact and therefore the most optical transparent. FT-IR and TGA results show that the samples are less hydroxygen containing owing to the hydrophobicity of the dimethyl groups.