From droplets and particles to hierarchical spatial organization: nanotechnology challenges for microfluidics. - In: Proceedings of the WSEAS international conferences, ISBN 978-960-474279-0, (2011), S. 237-244
ESR and LESR X-band study of morphology and charge carrier interaction in blended P3HT-SWCNT and P3HT-PCBM-SWCNT solid thin films. - In: Synthetic metals, Bd. 161 (2011), 21/22, S. 2241-2248
http://dx.doi.org/10.1016/j.synthmet.2011.08.027
Adressierung mehrdimensionaler Konzentrationsräume in der Mikrofluidsegmenttechnik. - In: Proceedings, (2011), S. 945-947
Mikropumpe für Mikrobioreaktoren. - In: Proceedings, (2011), S. 923-926
Mikro-Bioreaktorsystem zur 3D-Kultivierung mit polymeren Zellträgern. - In: Proceedings, (2011), S. 500-503
Elektrisch geschaltete Mikrofluidsegmente für die "Segment-on-Demand"-Technik. - In: Proceedings, (2011), S. 70-73
Multi-walled carbon nanotubes as electrode materials for electrochemical studies of organometallic compounds in organic solvent media. - In: Monatshefte für Chemie, ISSN 1434-4475, Bd. 142 (2011), 3, S. 233-242
Films of vertically aligned multi-walled carbon nanotubes (MWCNT) were selectively synthesized on silicon dioxide substrate by catalytic chemical vapor deposition using either benzene or acetonitrile as carbon source and ferrocene (1% w/w) as catalyst. The MWCNT were extensively characterized by using scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and Raman spectroscopy. In order to examine the prospective application of the fabricated MWCNT films for the detection of electro-active compounds in organic solvent media, electrochemical studies of the oxidation of cobaltocene (CoCp(2)) to cobaltocenium cation (CoCp (2) (+)) (Cp = cyclopentadienyl anion) in acetonitrile were performed on these films. For this purpose, cyclic voltammetry and electrochemical impedance spectroscopy were employed. The electrochemical parameters for the CoCp (2) (+/0) couple in acetonitrile were derived and compared with those obtained using a conventional glassy carbon electrode. The results demonstrate that the synthesized MWCNT films are promising electrode materials for the electrochemical detection of electro-active species in organic solvents. The MWCNT film formed upon decay of benzene has higher capacitance, less Warburg impedance, and less charge transfer resistance, and consequently it provides faster electron transfer kinetics.
http://dx.doi.org/10.1007/s00706-011-0454-1
Comparative study of mono- and dinuclear complexes of late 3d-metal chlorides with N,N-dimethylformamide in the gas phase. - In: Inorganic chemistry, ISSN 1520-510X, Bd. 50 (2011), 3, S. 771-782
Mono- and binuclear complexes of N,N-dimethylformamide (DMF) with chlorides of the divalent, late 3d metals M = Co, Ni, Cu, and Zn are investigated by means of electrospray ionization (ESI). Specifically, ESI leads to monocations of the type [(DMF)(n)MCl](+) and [(DMF)(n)M(2)Cl(3)](+), of which the species with n = 2 and 3 were selected for in-depth studies. The latter include collision-induced dissociation experiments, gas-phase infrared spectroscopy, and calculations using density functional theory. The mononuclear complexes [(DMF)(n)MCl](+) almost exclusively lose neutral DMF upon collisional activation with the notable exception of the copper complex, for which also a reduction from CuII to CuI concomitant with the release of atomic chlorine is observed. For the dinuclear clusters, there exists a competition between loss of a DMF ligand and cluster degradation via loss of neutral MCl(2) with decreasing cluster stability from cobalt to zinc. For the specific case of [(DMF)(n)ZnCl](+) and [(DMF)(n)Zn(2)Cl(3)](+), ion-mobility mass spectrometry indicates the existence of two isomeric cluster ions in the case of [(DMF)(2)Zn(2)Cl(3)](+) which corroborates parallel theoretical predictions.
http://dx.doi.org/10.1021/ic100759h
Clustering of palladium(II) chloride in acetonitrile solution investigated by electrospray mass spectrometry. - In: International journal of mass spectrometry, ISSN 1387-3806, Bd. 304 (2011), 1, S. 9-14
Solutions of palladium chloride in acetonitrile are investigated by means of electrospray ionization mass spectrometry (ESI-MS). In contrast to several other metal salts previously investigated using ESI-MS, PdCl(2)2 has a pronounced tendency for aggregation to yield [Pd(m)Cl(2m-1)(CH(3)CN)(n)](+) clusters in the positive ion mode and [Pd(m)Cl(2m+1)](-) clusters when the negative ions are sampled, respectively. The observation of these oligomers parallels polymeric structures of PdCl(2) in the solid phase. The positive ions are most abundant for m = 2 and generally associated with several molecules of the solvent, whereas many different cluster sizes occur for the anions which generally do not appear as solvent associates. Parallel conductivity measurements in the condensed phase lend support to a pronounced tendency for aggregation of PdCl(2) in acetonitrile solution.
http://dx.doi.org/10.1016/j.ijms.2011.02.014
Determination of impedance spectroscopic behavior of triphenylphosphine on various electrodes. - In: Analytical letters, ISSN 1532-236X, Bd. 44 (2011), 8, S. 1416-1430
The electrochemical oxidation of triphenylphosphine (Ph(3)P) was investigated by means of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) on glassy-carbon (GC), gold (Au) and multi-walled carbon nanotubes (MWCNT) in acetonitrile (ACN), dichloromethane (DCM), and cyclohexanone (CHN). The electron-transfer kinetics of the redox couple PPh(3)/Ph(3)P(center dot+) on various electrodes was found to increase with the order: Au < MWCNT < GC. The EIS results verify that GC provides faster charge-transfer kinetics since it affords less charge-transfer resistance and thus lower electron-transfer barrier from other electrodes tested. In DCM and CHN greater deviation from reversibility was observed which can be attributed to the poorer polarity of the solvents, which provides an additional barrier for the electron-transfer process.
http://dx.doi.org/10.1080/00032719.2010.520387