Dissolution, characterization and photo functionalization of carbon nanotubes

A simple method to disperse carbon nanotubes (CNTs) has been achieved, which gives two photofunctionalized CNTs, hydrazine nanotubes (h-CNTs) and 1,3,4-oxadiazole nanotubes (o-CNTs). Results from FTIR, H-1 NMR spectroscopy and TEM observations showed that the functionalization was successful. The modified nanombes can dissolve in most of the nonpolar organic solvents and no precipitate was observed in the solution of the nanombes even after 2 months. The functionalized nanotubes showed photo-electronic properties, which is due to the attachment of the function groups to them as proved by steady-state fluorescence spectroscopy. Both h-CNTs and o-CNTs showed good thermal stability below 300 C and might be used as functional materials.

Synthesis and characterization of photo-cross-linked hydrogels based on biodegradable polyphosphoesters and poly(ethylene glycol) copolymers

Novel biodegradable hydrogels by photo-cross-linking macromers based on polyphosphoesters and poly(ethylene glycol) (PEG) are reported. Photo-cross-linkable macromers were synthesized by ring-opening polymerization of the cyclic phosphoester monomer 2-(2-oxo-1,3,2-dioxaphospholoyloxy) ethyl methacrylate (OPEMA) using PEG as the initiator and stannous octoate as the catalyst. The macrorners were characterized by H-1 NMR, Fourier transform infrared spectroscopy, and gel permeation chromatography measurements. The content of polyphosphoester in the macromer was controlled by varying the feed ratio of OPEMA to PEG. Hydrogels were fabricated by exposing aqueous solutions of macromers with 0.05% (w/w) photoinitiator to UV light irradiation, and their swelling kinetics as well as degradation behaviors were evaluated. The results demonstrated that cross-linking density and pH values strongly affected the degradation rates. The macromers was compatible to osteoblast cells, not exhibiting significant cytotoxicity up to 0.5 mg/mL. "Live/dead" cell staining assay also demonstrated that a large majority of the osteoblast cells remained viable after encapsulation into the hydrogel constructs, showing their potential as tissue engineering scaffolds.

Direct patterning of polymer-based photo luminescent structures with a mask

We report a simple method to directly pattern polymer-based photo luminescent material, i.e. a prepatterned mask is placed a close distance above it. The final structure is a positive replica of the lateral structures in the mask with submicrometer resolution. The comparison of luminescence efficiency before and after patterning indicates almost no degradation in optical property of the material during the experiments. The mechanism of pattern formation is also discussed.

Preparation, photo and electroluminescence properties of novel rare earth aromatic carboxylates

Novel soluble rare earth aromatic carboxylates were prepared. The triplet energy level of organic ligand was measured. The photoluminescence properties of the Tb3+ and EU3+ aromatic carboxylates and lifetimes were investigated, which indicated that these rare earth complexes have high quantum efficiency. Because of their excellent solubility, polymer-doping rare earth carboxylates were fabricated as thin Films by spin-coating method and their luminescence properties were studied. Some rare earth organic light-emitting diodes were successfully fabricated which performed high pure color. The maximum luminance of the device of ITO/PVK/PVK :Th (AS)(3)Phen: PBD/PBD/Al is 32 cd(.)m(-2) at 28 V.

The photo-induced decarbonylation of Cp ' M(NO)(CO)(2) (M = Cr, Mo, W) with diorgano dichalcogenides (R2E2; E = S, Se; R = Me, Ph)

The photo-induced decarbonylation of Cp'Cr(NO)(CO)(2) (1a) in MeCN solution in the presence of R2E2 (E = S, Se; R = Me, Ph) leads to the formation of chalcogenolato-bridged binuclear complexes Cp-2'Cr-2(NO)(2)(mu -ER)(2) [E = S; R = Me (2a), Ph (3a); E = Se, R = Me (4a), Ph (5a)] while reactions between Cp'M(NO)(CO)(2) [M = Mo (1b), W (1c)] and Ph2E2 (E = S, Se) result in mononuclear complexes Cp'M(NO)(EPh)(2) [M = Mo; E = S (9b), Se (10b); M = W, E = S (11c), Se (12c)]. The corresponding reactions of (1b) with Me2E2 (E = S, Se) yielded both mono and binuclear complexes: Cp'Mo(NO)(SeMe)(2) (8b), Cp-2'Mo-2(NO)(2)(mu -EMe)(2) [E = S (6b), Se (7b)]. The new complexes have been characterized by i.r., H-1-, C-13-n.m.r. spectra and by electron-impact mass spectrometry.