Influence of concentration of supporting electrolyte on electrochemistry of redox systems on multi-walled carbon nanotubes. - In: Physics and chemistry of liquids, ISSN 1029-0451, Bd. 50 (2012), 5, S. 661-668
In the present work, the effect of the concentration of supporting electrolyte on the electrochemical behaviour of the redox couple ferrocyanide/ferricyanide, [Fe(CN)(6)](3-/4-) on film consisted of multi-walled carbon nanotubes (MWCNTs) was investigated. The MWCNTs were selectively grown on oxidised silicon substrate by means of catalytic chemical vapour deposition (CCVD) technique with decay of acetonitrile (ACN) in the presence of ferrocene (FeCp2) that served as catalysts. For the electrochemistry studies, the techniques of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in three-electrode system were employed. The correlation between the solution's ionic strength and the electrochemical impedance parameters are discussed.
http://dx.doi.org/10.1080/00319104.2012.663496
Electrochemical responses and sensitivities of films based on multi-walled carbon nanotubes in aqueous solutions. - In: Journal of solution chemistry, ISSN 1572-8927, Bd. 41 (2012), 11, S. 2047-2057
http://dx.doi.org/10.1007/s10953-012-9925-1
Using C 60 fullerenes for photodynamic inactivation of mosquito iridescent viruses. - In: Journal of enzyme inhibition and medicinal chemistry, ISSN 1475-6374, Bd. 27 (2012), 4, S. 614-617
This article describes the photodynamic inactivation of mosquito iridescent virus (MIV) Aedes flavescens in the presence of water-soluble C-60 fullerenes. It has been observed that the photodynamic inactivation of MIV for about 1 h reduces the infectious titre of the virus in large wax-moth larvae Galleria mellonella to 4.5 lg ID50 /mL. The influence of the C-60 concentration on its anti-viral activity was tested in the concentration range from 1 to 0.001 mg/mL. It has been found that C-60 is able to inactivate the iridovirus even in low concentrations. Consequently, the findings of this work suggest that photoexcited C-60 fullerenes can be successfully used for the inactivation of iridoviruses in biological systems.
http://dx.doi.org/10.3109/14756366.2011.601303
Effect of iron-doped multi-walled carbon nanotubes on lipid model and cellular plasma membranes. - In: Materials science & engineering, ISSN 1873-0191, Bd. 32 (2012), 6, S. 1486-1489
The aim of the present work was the study of the interaction of multi-walled carbon nanotubes filled with iron (Fe-MWCNTs) with bimolecular lipid model membrane (BLM) and cellular plasma membrane (PM). The findings demonstrate that the Fe-MWCNTs adsorb on the BLM surface with possible partial build up in the hydrophobic area of fatty acid residues of lipids and increase its specific conductivity and capacity. Furthermore, upon interaction with the PM, the Fe-MWCNTs form channels which allow the flow of water to the cells and the externalization of phosphatidylserine from the inner to the outer PM leaflet.
http://dx.doi.org/10.1016/j.msec.2012.04.029
Electrochemical and thermodynamic properties of hexacyanoferrate(II)/(III) redox system on multi-walled carbon nanotubes. - In: The journal of chemical thermodynamics, ISSN 1096-3626, Bd. 54.2012 (Nov.), S. 35-40
Novel films consist of multi-walled carbon nanotubes (MWCNT) were fabricated by means of catalytic chemical vapor deposition (CVD) technique with decomposition of either acetonitrile (ACN) or benzene (BZ) using ferrocene (FeCp2) as catalyst. The electrochemical and thermodynamic behavior of the ferrocyanide/ferricyanide, [Fe(CN)(6)](3-/4-) redox couple on synthesized MWCNT-based films was investigated by means of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques at T = (278.15, 283.15, 293.15, and 303.15) K. The redox couple [Fe(CN)(6)](3-/4-) behaves quasi-reversibly on fabricated MWCNT-based films and its reversibility is enhanced upon increasing temperature. Namely, the findings establish that with the rise in temperature the barrier for interfacial electron transfer decreases, leading, consequently, to an enhancement of the kinetics of the charge transfer process. According to thermodynamics the equilibrium of the redox process is shifted towards the formation of [Fe(CN)(6)](3-) at elevated temperatures.
http://dx.doi.org/10.1016/j.jct.2012.03.018
Water-soluble pristine fullerenes C60 increase the specific conductivity and capacity of lipid model membrane and form the channels in cellular plasma membrane. - In: Journal of biomedical nanotechnology, ISSN 1550-7041, Bd. 8 (2012), 3, S. 522-527
Im Titel ist "60" tiefgestellt
The aim of the present work was the investigation of the interaction of water-soluble pristine fullerenes C-60 with bimolecular lipid model membrane (BLM) and cellular plasma membrane (PM). The findings demonstrate that the fullerenes C-60 at low concentrations, namely in the concentration range of 1.0 x 10(-4)-1.0 mg . ml(-1), are preferentially incorporated into the hydrophobic region of BLM, increasing, thus, its specific conductivity and specific capacity. Furthermore, upon interaction of fullerenes C-60 with PM, pores or other type of local defects are formed, which are wide enough in order to permit the passage of water molecules across the cell membrane resulting to the externalization of phosphatidylserine from the inner to the outer PM leaflet.
http://dx.doi.org/10.1166/jbn.2012.1404
Oxidation of dopamine on multi-walled carbon nanotubes. - In: Journal of solid state electrochemistry, ISSN 1433-0768, Bd. 16 (2012), 6, S. 2217-2226
Novel films consisting of multi-walled carbon nanotubes (MWCNTs) were fabricated by means of the chemical vapor deposition technique with decomposition of either acetonitrile (ACN) or benzene (BZ) in the presence of ferrocene (FeCp2) which served as catalyst. The electrochemical response of the two different kinds of MWCNT-based films, further referred to as MWCNT-ACN and MWCNT-BZ, towards the oxidation of dopamine (DA) to dopamine-o-quinone (DAQ) was tested by means of cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. Both MWCNT-based films exhibit quasi-reversible response towards DA/DAQ with some slight kinetic differences; specifically, the charge-transfer process was found to be faster on MWCNT-ACN (k (s) = 35.3 × 10(-3) cm s(-1)) compared to MWCNT-BZ (k (s) = 6.55 × 10(-3) cm s(-1)). The detection limit of MWCNT-BZ for DA (0.30 mu M) appears to be poorer compared to that of MWCNT-ACN (0.03 mu M), but nevertheless, both MWCNT-based films exhibit greater detection ability compared to other electrodes reported in the literature. The sensitivities of MWCNT-ACN and MWCNT-BZ towards DA/DAQ were determined as 0.65 and 0.22 A M-1 cm(-2), respectively. The findings suggest that the fabricated MWCNT-based electrodes can be successfully applied for the detection of molecules with biological interest.
http://dx.doi.org/10.1007/s10008-012-1647-1
Surface silanization of carbon nanofibers and nanotubes for altering the properties of epoxy composites. - Ilmenau, 2012. - Online-Ressource (PDF-Datei: VII, 124 Bl. , 3,41 MB) : Ilmenau, Techn. Univ., Diss., 2012
Parallel als Druckausg. erschienen
Diese Arbeit beschreibt die Oberflächenmodifizierung von Kohlenstoffnanofasern (CNFs) und mehrwandigen Kohlenstoffnanoröhren (MWCNTs) sowie die Eigenschaften von damit hergestellten Epoxid-Kompositen. Es wurden Korrelationen zwischen chemischen Oberflächenmodifizierungen und Kompositeigenschaften untersucht.Im ersten Teil wurden nach einer Oxidation zur Erzeugung von Carboxygruppen daran anknüpfend drei unterschiedliche Reaktionswege zur Silanisierung der oxidierten Oberflächen der nanoskaligen Kohlenstoffmaterialien untersucht:direkte Silanisierung mit 3-Glycidoxypropyltrimethoxysilan Reduktion der Carboxygruppen zu den alkoholischen Hydroxygruppen und Silanisierung mit 3-Aminopropyltrimethoxysilan Silanisierung mit 3-Isocyanatopropyltriethoxysilan und weitere Silanisierung mit 3-AminopropyltrimethoxysilanDie Oxidation sowie die Silanisierung der CNFs und MWCNTs wurden systematisch und detailliert anhand verschiedener analytisch-chemischer Methoden charakterisiert.Im zweiten Teil wurden CNFs oder MWCNTs in Epoxidharzen dispergiert und die physikalischen Eigenschaften der daraus hergestellten Nanokomposite beschrieben. So zeigten Epoxid-Komposite, die mit silanisierten CNFs versetzt wurden, verbesserte mechanische Eigenschaften. Auch die elektrische Leitfähigkeit der Epoxid-Komposite stieg mit zunehmendem Gehalt der Nanofüllstoffe, wobei die elektrische Leitfähigkeit von Epoxid-Kompositen mit silanisierten CNFs aufgrund der isolierenden Silanschicht niedriger war als die der Epoxid-Komposite mit unmodifizierten CNFs. Bei MWCNTs-Epoxid-Kompositen bewirkte die Silanisierung eine größere Änderung der elektrischen Leitfähigkeit im Vergleich zu den CNFs-Epoxid-Kompositen. Das Einbringen von CNFs in das Epoxidharz erhöhte die thermische Leitfähigkeit. Die Wärmeleitfähigkeit der Epoxid-Komposite konnte in Abhängigkeit von der Silanmenge auf den CNFs höher oder niedriger sein als die der Epoxid-Komposite mit unmodifizierten CNFs. Die MWCNTs in den Epoxid-Kompositen konnten durch Anlegen eines elektrischen Wechselstromfeldes parallel zu den Feldlinien ausgerichtet werden, was Messungen einer anisotropen elektrischen Leitfähigkeit an den Kompositen belegten.Die nasschemische Silanisierung der nanoskaligen Kohlenstoffmaterialien stellt eine vielseitige und einfache Methode dar, die Eigenschaften von Polymerkompositen gezielt zu modifizieren. Diese Änderungen der Materialeigenschaften wurden dann vor allem durch stärkere Wechselwirkungen an den Grenzflächen zwischen Füllstoffen und Polymer sowie durch eine bessere Verteilung der Füllstoffe in der Polymermatrix erreicht.
https://www.db-thueringen.de/servlets/DocumentServlet?id=20432
Structure-electrical resistivity relationship of N-doped multi-walled carbon nanotubes. - In: Journal of materials science, ISSN 1573-4803, Bd. 47 (2012), 5, S. 2390-2395
Nitrogen-doped multi-walled carbon nanotubes (N-MWCNT) were synthesized by means of catalytic chemical vapor deposition technique using acetonitrile as carbon source material and ferrocene as catalyst. The structure of the synthesized N-MWCNT was characterized by means of microscopic (SEM, HRTEM) as well as spectroscopic (FTIR, Raman) techniques. Furthermore, the specific resistivity and the electrochemical properties of N-MWCNT were investigated and compared with those of pristine MWCNT. The results are discussed in terms of structural differences between pristine MWCNT and N-MWCNT.
http://dx.doi.org/10.1007/s10853-011-6059-6
Low-temperature 1 H-NMR spectroscopic study of doxorubicin influence on the hydrated properties of nanosilica modified by DNA. - In: Journal of materials science, ISSN 1573-4838, Bd. 22 (2011), 3, S. 525-532
The effect of the anticancer drug-doxorubicin (Dox) on hydration properties of a nanocomposite material deposited on silica and modified by small amount of DNA (0.6 wt%) was studied by means of (1)H NMR spectroscopy at low temperatures (in the range of 200-280 K). Signals of either weakly (WAW) or strongly (SAW) associated water, as well as water associated with electrondonor groups of the composite surface (ASW), were observed. The findings reveal that, depending on the temperature and the composition of the dispersion medium, fast molecular exchange takes place between different forms of interphase water. The presence of Dox (0.1-0.2 wt%) in the dispersion medium leads to change of the relative concentrations of different forms of water.
http://dx.doi.org/10.1007/s10856-011-4237-3