Electrochemistry on multi-walled carbon nanotubes in organic solutions. - In: Journal of solution chemistry, ISSN 1572-8927, Bd. 40 (2011), 9, S. 1645-1656
The oxidation of ferrocene (FeCp(2)) to ferrocenium cation were determined. On both electrodes tested, the electron transfer process was found to be quasi-reversible and diffusion controlled in all investigated solvent mixtures. The E (1/2) values were shifted toward less positive potentials with the enrichment of mixtures in MeOH, due probably to the larger Lewis basicity of the MeOH molecules. Furthermore, values of both D and k (s) diminish with the increase of MeOH content following the progressive increase of viscosity of the solvent medium. Among the electrodes probed, GC provides faster electrochemical process since it affords less charge-transfer resistance (R (ct)), and consequently, an insignificant barrier for interfacial electron transfer.
http://dx.doi.org/10.1007/s10953-011-9735-x
Thermodynamic studies on silver and thallium nitrate. - In: International journal of thermophysics, ISSN 1572-9567, Bd. 32 (2011), 9, S. 1950-1965
The molar conductivities (Lambda) of aqueous solutions of silver nitrate and thallium nitrate were measured in the temperature range from 291.15 K to 314.15 K. The Lambda values were analyzed using the Lee-Wheaton model, and the limiting molar conductivities (Lambda(o)) as well as the association equilibrium constants (K(A)) were derived. The center-to-center distances (alpha) of the formed ion pairs were considered to be equal to the Bjerrum's distance. The limiting ion conductivities (lambda(+/-)) were determined. The thermodynamic functions, Gibbs energy (Delta G(A)), enthalpy (Delta H(A)), and entropy (Delta S(A)) for the ion-pair formation process were determined as well. The results are discussed in terms of ion-ion and ion-solvent interactions.
http://dx.doi.org/10.1007/s10765-011-1046-3
Structure and magnetic properties of multi-walled carbon nanotubes modified with cobalt. - In: Carbon, ISSN 1873-3891, Bd. 49 (2011), 13, S. 4443-4448
The magnetic properties of multi-walled carbon nanotubes (MWCNTs) modified with cobalt nanoparticles were studied in the temperatures and magnetic field range of (4.2-290) K and (0.03-5) T, respectively. Nanoparticles of cobalt encapsulated inside MWCNTs were obtained by using the chemical vapor deposition technique. The low temperature SQUID magnetization measurements were supplemented with structural investigations by means of high-resolution transmission electron microscopy, scanning electron microscopy as well as thermogravimetric and X-ray diffraction analysis. X-ray diffraction revealed the presence of MWCNTs, f.c.c. Co and h.c.p. Co phases. The magnetic characterization provided the remanent magnetization value (M(R)) of about 0.07 emu/g (similar to 40% of the saturation moment), while the coercive field (H(C)) value amounts to 600 Oe. Both parameters M(R) and H(C) slightly decrease with the rise of temperature. The substantial magnetization increase observed at low temperatures suggests the existence of nano Co clusters (in the atomic scale size).
http://dx.doi.org/10.1016/j.carbon.2011.06.039
Magnetische Eigenschaften von mit Kobalt modifizierten mehrwandigen Kohlenstoffnanoröhren :
Magnetic properties of multi-walled carbon nanotubes modified with cobalt. - In: Materials science and engineering technology, ISSN 1521-4052, Bd. 42 (2011), 1, S. 29-32
Magnetic properties of multi-walled carbon nanotubes (MWCNT) modified with cobalt were studied in detail in the temperature range (4.2-290) K. MWCNT which encapsulate Co nanoparticles were obtained using CVD methods. The low temperature SQUID magnetization measurements were supplemented by structural investigations with thermogravimetric analysis, HRTEM and SEM.
http://dx.doi.org/10.1002/mawe.201100725
Schrittweise Dispersion in der Resonanz-Raman-Streuung von einwandigen Kohlenstoffnanoröhren im niedrigen Frequenzbereich :
Low-frequency two-phonon modes step-like dispersion in resonance raman scattering of single-walled carbon nanotubes. - In: Materials science and engineering technology, ISSN 1521-4052, Bd. 42 (2011), 1, S. 33-36
Single-walled carbon nanotubes (SWCNT) synthesized by the arc-discharge method were investigated by Raman spectroscopy in detail. In particular, the sharp peaks in (200.-400) cm(-1) spectral range of SWCNT, associated with low-frequency two-phonon modes, arising from flexural 2D graphite (graphene) ZO- (optical branch) and ZA- (acoustical branch) modes, have been firstly observed.
http://dx.doi.org/10.1002/mawe.201100726
Photodynamische Inaktivierung des Mosquito Iridovirus (MIV) durch C 60 Fullerene :
Photodynamic inactivation of mosquito iridovirus (MIV) by C 60 fullerenes. - In: Materials science and engineering technology, ISSN 1521-4052, Bd. 42 (2011), 2, S. 136-138
It was shown that water soluble C(60) fullerenes under visible light interact with iridovirus virions of mosquito Aedes flavescens and lead to their destruction. Specifically, the photodynamic inactivation of mosquito iridovirus during 1 h reduced the infectious virus titer in large wax-moth larvae Galleria mellonella on 4 lg ID50/ml. Therefore, for inactivation of iridoviruses in biological systems it is appropriate to use the photoexcited C(60) fullerenes.
http://dx.doi.org/10.1002/mawe.201100745
Sol-Gel induzierte Leitfähigkeitsmodulation von Netzwerken aus Kohlenstoffnanoröhren (CNTs) und deren Ursachen. - Ilmenau, 2011. - Online-Ressource (PDF-Datei: 142 S., 5541 KB) : Ilmenau, Techn. Univ., Diss., 2011
Parallel als Druckausg erschienen
Diese Arbeit behandelt eine neue Methode zur Herstellung einer hochleitfähigen Schichtaus einem CNT/Sol-Gel Verbund. Dazu werden zunächst dünne CNT Netzwerke auf ein elektrisch nicht leitfähiges Substrat aufgebracht und anschließend mit dem Sol-Gel imTauchbeschichtungsverfahren penetriert. Neben dispergentbehafteten CNT Netzwerken wird diese Methode ebenso für dispergentfreie angewendet. Anschließende thermische Prozessierungen der Beschichtungen erlauben dabei die Veränderung der elektrischen Eigenschaften des Komposits aufgrund thermisch induzierter Verdichtungsmechanismen des Sol-Gels. Aufgrund der Möglichkeit der äquivalenten Prozessierung von Sol-Gel freien CNT Netzwerken ist es darüber hinaus möglich, den Einfluss des Sol-Gels auf die CNT Netzwerke zu studieren. Im Zuge dessen wird die unerwartet erhöhte elektrische Leitfähigkeit thermisch speziell behandelter CNT/Sol-Gel Komposite (im Vergleich zum Sol-Gel freienÄquivalent) betrachtet und anhand morphologischer Untersuchungen und temperaturabhängigen elektrischen Eigenschaften die Auswirkungen des Sol-Gels auf das CNTNetzwerk beurteilt. Durch die Anpassung von theoretischen Modellen an die gefundenen experimentellen Daten konnten hierzu spezifische Kennwerte der Beschichtungen ermittelt und miteinander verglichen werden. Es stellte sich heraus, dass ein optimierter elektrischer CNT-CNT Übergang der Komposite maßgeblich verantwortlich für die verbesserten elektrischen Eigenschaften gegenüber der Sol-Gel freien Referenz ist.
https://www.db-thueringen.de/servlets/DocumentServlet?id=18914
Thermal diffusivity of nanocarbon composites. - In: Polymer composites, ISSN 1548-0569, Bd. 32 (2011), 1, S. 14-17
This study was performed to measure the thermal diffusivity of different types of nanocarbon composites. Thermoexfoliated graphite (TEG), ultrasonically dispersed TEG, and multiwalled carbon nanotubes were used as fillers in epoxy polymer matrixes. The nanocarbon filler content was 1-10 wt%. The temperature dependence of the thermal conductivity and the heat capacity were extensively characterized in the temperature range between 150 and 425 K. For this purpose, the thermal diffusivity of the composites was investigated by two experimental methods: dynamic A-calorimeter and photoacoustic. The comparative analysis of thermal diffusivity of compacted TEG samples with different densities and of nanocarbon-epoxy with different filler content was carried out. It was found that for the composites with a low distribution of the nanocarbon filler, the thermal diffusivity increases and that the value is determined by the structural and morphological properties of the filler. The orientation function for the TEG-epoxy composites and the compact TEG samples differs due to the epoxy matrix that reduced anisotropy of the composite. POLYM. COMPOS., 2011. (C) 2010 Society of Plastics Engineers
https://doi.org/10.1002/pc.21009
Penetration based CNT/Sol-Gel composite films and their remarkable electrical properties. - In: Microelectronic engineering, Bd. 88 (2011), 8, S. 2513-2525
In this work we present a novel method for CNT/Sol-Gel film preparation, combining low resistivity and improved adhesion behaviour on glass substrates. Naturally occurring voids, with diameters of 50-100 nm, in sprayed CNT networks are used for Sol–Gel penetration via dip coating method. Thermal treatments, for composite film densification, in the range of 200-700 ˚C are investigated and electrical properties were compared to identically treated reference samples with the same batch of nanotubes but without Sol-Gel. The resistivity of such composite films, with best value of similar to 0.03 Omega cm for MWNTs, is two orders of magnitudes lower than previously reported for CNT/Sol-Gel composites. Surprisingly the surface resistance of the composite film shows 25% improvement compared to thermally equal treated pure CNT films. In addition, crosscut adhesion behaviour is investigated, including tape test, showing good performance for composite films, where Sol-Gel acts as an adhesion promoter.
http://dx.doi.org/10.1016/j.mee.2011.01.015
Interaction of N-fluorescein-5-isothiocyanate pyrrolidine-C60 with a bimolecular lipid model membrane. - In: Materials science & engineering, ISSN 1873-0191, Bd. 31 (2011), 5, S. 1148-1150
http://dx.doi.org/10.1016/j.msec.2011.02.026