Chemical modification of MWCNTs via oxidation followed by side wall functionalization using polyethylene glycol （PEG） and octadecylamine （ODA）, separately, was studied. Different characterization techniques such a...Chemical modification of MWCNTs via oxidation followed by side wall functionalization using polyethylene glycol （PEG） and octadecylamine （ODA）, separately, was studied. Different characterization techniques such as FTIR spectrometery, thermogravimetric analysis （TGA）, scanning electron microscopy （SEM）, X-ray diffraction （XRD）, and solubility in different solvents were performed for the oxidized MWCNTs, MWCNTs-PEG and MWCNTs-ODA. The characterization techniques proved the presence of the functional groups on the MWCNTs surface. Thermal gravimetric analysis revealed that nearly 16% （by weight） of the MWCNTs were functionalized with PEG and 39% （by weight） was functionalized with ODA.展开更多
One of the primary aims of the actinide community within nanoscience is to develop a good understanding similar to what is currently the case for stable elements. As a consequence, efficient, reliable and versatile sy...One of the primary aims of the actinide community within nanoscience is to develop a good understanding similar to what is currently the case for stable elements. As a consequence, efficient, reliable and versatile synthesis techniques dedicated to the formation of new actinide-based nano-objects （e.g., nanocrystals） are necessary. Hence, a ＂library＂ dedicated to the preparation of various actinidebased nanoscale building blocks is currently being developed. Nanoscale building blocks with tunable sizes, shapes and compositions are of prime importance. So far, the non-aqueous synthesis method in highly coordinating organic media is the only approach which has demonstrated the capability to provide size and shape control of actinide-based nanocrystals （both for thorium and uranium, and recently extended to neptunium and plutonium）. In this paper, we demonstrate that the non-aqueous approach is also well adapted to control the chemical composition of the nanocrystals obtained when mixing two different actinides. Indeed, the controlled hot co-injection of thorium acetylacetonate and uranyl acetate （together with additional capping agents） into benzyl ether can be used to synthesize thorium/uranium mixed oxide nanocrystals covering the full compositional spectrum. Additionally, we found that both size and shape are modified as a function of the thorium：uranium ratio. Finally, the magnetic properties of the different thorium/uranium mixed oxide nanocrystals were investigated. Contrary to several reports, we did not observe any ferromagnetic behavior. As a consequence, ferromagnetism cannot be described as a universal feature of nanocrystals of non-magnetic oxides as recently claimed in the literature.展开更多
文摘Chemical modification of MWCNTs via oxidation followed by side wall functionalization using polyethylene glycol （PEG） and octadecylamine （ODA）, separately, was studied. Different characterization techniques such as FTIR spectrometery, thermogravimetric analysis （TGA）, scanning electron microscopy （SEM）, X-ray diffraction （XRD）, and solubility in different solvents were performed for the oxidized MWCNTs, MWCNTs-PEG and MWCNTs-ODA. The characterization techniques proved the presence of the functional groups on the MWCNTs surface. Thermal gravimetric analysis revealed that nearly 16% （by weight） of the MWCNTs were functionalized with PEG and 39% （by weight） was functionalized with ODA.
文摘One of the primary aims of the actinide community within nanoscience is to develop a good understanding similar to what is currently the case for stable elements. As a consequence, efficient, reliable and versatile synthesis techniques dedicated to the formation of new actinide-based nano-objects （e.g., nanocrystals） are necessary. Hence, a ＂library＂ dedicated to the preparation of various actinidebased nanoscale building blocks is currently being developed. Nanoscale building blocks with tunable sizes, shapes and compositions are of prime importance. So far, the non-aqueous synthesis method in highly coordinating organic media is the only approach which has demonstrated the capability to provide size and shape control of actinide-based nanocrystals （both for thorium and uranium, and recently extended to neptunium and plutonium）. In this paper, we demonstrate that the non-aqueous approach is also well adapted to control the chemical composition of the nanocrystals obtained when mixing two different actinides. Indeed, the controlled hot co-injection of thorium acetylacetonate and uranyl acetate （together with additional capping agents） into benzyl ether can be used to synthesize thorium/uranium mixed oxide nanocrystals covering the full compositional spectrum. Additionally, we found that both size and shape are modified as a function of the thorium：uranium ratio. Finally, the magnetic properties of the different thorium/uranium mixed oxide nanocrystals were investigated. Contrary to several reports, we did not observe any ferromagnetic behavior. As a consequence, ferromagnetism cannot be described as a universal feature of nanocrystals of non-magnetic oxides as recently claimed in the literature.
