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| 2. |
- Andersson, Claes-Henrik, et al.
(författare)
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Reproducibility and efficiency of carbon nanotube end-group generation and functionalization
- 2009
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Ingår i: European Journal of Organic Chemistry. - : Wiley. - 1434-193X .- 1099-0690. ; 26, s. 4421-4428
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Tidskriftsartikel (refereegranskat)abstract
- In a systematic fashion, several methods for esterification and amidation of single-walled carbon nanotubes have been evaluated with focus on efficiency and reproducibility in forming covalently functionalized products soluble in organic media. The outcome of transformations was determined using IR, Raman and NMR spectroscopy and by thermogravimetric analysis (TGA). Amidation proceeding via a SWNT-(COCl)(n) intermediate yielded the expected covalent product, whereas carboxylate salt formation dominated with other attempted methods. Esterification was achieved via the acyl chloride method and via alkylation of SWNT-(COO-)(n), the latter being the more efficient method. A non-covalent solubilizing interaction was obtained for RNH2 but not for ROH (R = octadecyl), proving that the most important non-covalent interaction between oxidatively cleaned SWNTs and octadecylamine is a salt formation. The outcome of the secondary functionalization of carboxyl units is highly reproducible for experiments carried out on the same batch of SWNT-(COOH)(n). Normalization of the outcome of the secondary functionalization to the composition of the different batches of starting materials reveals an overall high reproducibility of the secondary function alizations. The differences in outcome related to different commercial SWNT batches from the same synthetic procedure is negligible compared to that resulting from differences in overall carboxyl content after the primary HNO3 oxidative cleaning step. Hence, the composition of purified SWNT starting materials always needs to be assessed, in particular before drawing any conclusions concerning differences in outcome from reaction systems involving different sources of SWNT material.
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| 3. |
- Andersson, Claes-Henrik, et al.
(författare)
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Reversible Non-Covalent Derivatisation of Carbon Nanotubes with Glycosides
- 2009
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Ingår i: Soft Matter. - 1744-683X. ; 5:14, s. 2713-2716
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Tidskriftsartikel (refereegranskat)abstract
- SWNTs and MWNTs have been non-covalently functionalized with glycosides in a reversible manner, and fluorescence titrations have been used to quantify the formed supramolecular assemblies which for SWNTs exhibits increased water solubility.
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| 4. |
- Andersson, Claes-Henrik, et al.
(författare)
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Reversible non-covalent derivatisation of carbon nanotubes with glycosides
- 2009
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Ingår i: Soft Matter. - : Royal Society of Chemistry (RSC). - 1744-683X .- 1744-6848. ; 5:14, s. 2713-2716
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Tidskriftsartikel (refereegranskat)abstract
- SWNTs and MWNTs have been non-covalently functionalized with glycosides in a reversible manner, and fluorescence titrations have been used to quantify the formed supramolecular assemblies which for SWNTs exhibits increased water solubility.
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| 5. |
- Andersson, Henrik, et al.
(författare)
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The effect of mechanical stress on lateral-effect position sensitive detector characteristics
- 2006
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 563:1, s. 150-154
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Tidskriftsartikel (refereegranskat)abstract
- Position-sensitive detectors (PSDs) are widely used in noncontact measurement systems. In order to minimize the size of such systems, interest has increased in mounting the PSD chip directly onto printed circuit boards (PCBs). Stress may be induced in the PSD because of the large differences in thermal expansion coefficients, as well as the long-term geometrical stability of the chip packaging. Mechanical stress has previously been shown to have an effect on the performance of semiconductors. The accuracy, or linearity, of a lateral effect PSD is largely dependent on the homogeneity of the resistive layer. Variations of the resistivity over the active area of the PSD will result in an uneven distribution of photo-generated current, and hence an error in the readout position. In this work experiments were performed to investigate the influence of anisotropic mechanical stress in terms of nonlinearity. PSD chips of 60×3 mm active area were subjected, respectively, to different amounts of compressive and tensile stress to determine the influence on the linearity.
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