RESUMO
The direct diazotization of the sp(2) carbon network of graphene and multi-walled carbon nanotubes (MWNTs) is one of the many methods employed to introduce functional groups into these nanostructures. Herein, a methodical study on solvent-free diazotization with ethynylaniline in the presence of isoamyl nitrite is reported. Thermogravimetric analysis and UV-visible, infrared and Raman spectroscopies are used to precisely determine the degree of modification, confirm the presence of physisorption and describe the mechanism of elimination of the modifying groups. The results suggest that the same synthetic protocol in both cases leads to a certain degree of covalent modification, whilst a proportion of the modifying groups remains adsorbed to the carbon nanostructure. A higher level of global modification was observed for MWNTs. It was found that the elimination mechanism of the covalently-linked modifiers is identical for both nanostructures and involves two steps; acetylenic-aromatic bond rupture in the modifier followed by modifier-carbon nanostructure cleavage.
Assuntos
Grafite/química , Nanotubos de Carbono/química , Acetileno/análogos & derivados , Acetileno/química , Compostos de Anilina/química , Análise Espectral Raman , TemperaturaRESUMO
Graphene flakes covalently modified with a conjugated polymer, poly[(9,9-dihexylfluorene)-co-alt-(9,9-bis-(6-azidohexyl)fluorene)] (PFA), were efficiently synthesised by a Cu-catalysed Huisgen 1,3-dipolar cycloaddition between alkyne-modified graphene and an azide-functionalised polymer. Two approaches for the modification of graphene with alkyne groups were investigated (coupling with a diazonium salt generated in situ or an amidation reaction) and the optimum conditions determined. The success of the click-coupling approach was confirmed by FTIR, (1)Hâ NMR, Raman, and X-ray photoelectron spectroscopy (XPS). The absorption and emission spectra of the click product show a strong solvent dependency.
Assuntos
Alcinos/química , Fluorenos/química , Grafite/química , Polímeros/química , Solventes/química , Eletrônica , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Espectroscopia Fotoeletrônica , SoluçõesRESUMO
A general route for the functionalization of graphene and graphene derivatives with a low molecular weight polymer by thiol-radical reactions is reported. Polymer-modified graphene is employed as a filler for high density polyethylene to generate materials with good electrical conductivity.
RESUMO
A synthetic strategy is developed that allows for the facile functionalization of carbon nanostructures thus providing the possibility of comparing the striking different optical and electrochemical properties of ensembles based on the diketopyrrolopyrrole (DPP) chromophore covalently attached to either [60]fullerene or graphene.
RESUMO
Hybrid materials composed of graphene and conjugated poly(fluorene-alt-phenylene) endowed with redox-active anthraquinone moieties are prepared. Remarkable changes in the electronic properties of the polymer are observed. Effective interactions among the pendant anthraquinone and graphene, likely due to π-π stacking, are confirmed.