4659
2009
eng
postprint
0
2010-11-08
--
--
Polymer hydrogel/polybutadiene/iron oxide nanoparticle hybrid actuators for the characterization of NiTi implants
One of the main issues with the use of nickel titanium alloy (NiTi) implants in cardiovascular implants (stents) is that these devices must be of very high quality in order to avoid subsequent operations due to failing stents. For small stents with diameters below ca. 2 mm, however, stent characterization is not straightforward. One of the main problems is that there are virtually no methods to characterize the interior of the NiTi tubes used for fabrication of these tiny stents. The current paper reports on a robust hybrid actuator for the characterization of NiTi tubes prior to stent fabrication. The method is based on a polymer/hydrogel/magnetic nanoparticle hybrid material and allows for the determination of the inner diameter at virtually all places in the raw NiTi tubes. Knowledge of the inner structure of the raw NiTi tubes is crucial to avoid regions that are not hollow or regions that are likely to fail due to defects inside the raw tube. The actuator enables close contact of a magnetic polymer film with the inner NiTi tube surface. The magnetic signal can be detected from outside and be used for a direct mapping of the tube interior. As a result, it is possible to detect critical regions prior to expensive and slow stent fabrication processes.
urn:nbn:de:kobv:517-opus-48589
4858
Materials. - 2 (2009), 1, S. 207 - 220, DOI: 10.3390/ma2010207
<hr>The article was originally published by Molecular Diversity Preservation International:
<br><a href="http://www.mdpi.com/journal/materials">
Materials</a>. - 2 (2009), 1, S. 207-220<br>
ISSN 1996-1944<br>
DOI <a href="http://dx.doi.org/10.3390/ma2010207"> 10.3390/ma2010207</a>
Aleksandra Jeličić
Alwin Friedrich
Katarina Jeremić
Gerd Siekmeyer
Andreas Taubert
Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
paper 161
eng
uncontrolled
NiTi
eng
uncontrolled
inner surface
eng
uncontrolled
hydrogel
eng
uncontrolled
polybutadiene
eng
uncontrolled
magnetic nanoparticles
Chemie und zugeordnete Wissenschaften
open_access
Institut für Chemie
Universität Potsdam
https://publishup.uni-potsdam.de/files/4659/pmnf161.pdf
31927
2009
2009
eng
article
1
--
--
--
Unprecedented, low cytotoxicity of spongelike calcium phosphate/poly(ethylene imine) hydrogel composites
Covalently crosslinked PEI hydrogels are efficient templates for calcium phosphate mineralization in SBF. In contrast to the PEI hydrogels, non-crosslinked PEI does not lead to calcium phosphate nucleation and growth in SBF. The precipitate is a mixture of brushite and hydroxyapatite. The PEI/calcium phosphate composite material exhibits a sponge like morphology and a chemical composition that is interesting for implants. Cytotoxicity tests using Dictyostelium discoideum amoebae show that both the non-mineralized and mineralized hydrogels have a very low cytotoxicity. This suggests that next generation PEI hydrogels, where also the degradation products are non-toxic, could be interesting for biomedical applications.
http://www3.interscience.wiley.com/cgi-bin/jhome/77002860
10.1002/mabi.200800266
1616-5187
allegro:1991-2014
10108278
Macromolecular bioscience. - ISSN 1616-5187. - 9 (2009), 2, S. 179 - 186
Andriy Shkilnyy
Ralph Gräf
Bernhard Hiebl
Axel T. Neffe
Alwin Friedrich
Juergen Hartmann
Andreas Taubert
Institut für Chemie
Referiert
31663
2009
2009
eng
article
1
--
--
--
Surprisingly high, bulk liquid-like mobility of silica-confined ionic liquids
Mesoporous silica monoliths were prepared by the sol - gel technique and. lled with 1-ethyl-3-methyl imidazolium [Emim]-X (X = dicyanamide [N(CN)(2)], ethyl sulfate [EtSO4], thiocyanate [SCN], and triflate [TfO]) ionic liquids (ILs) using a methanol-IL exchange technique. The structure and behavior of the ILs inside the silica monoliths were studied using X-ray scattering, nitrogen sorption, IR spectroscopy, solid-state NMR, and thermal analysis. DSC finds shifts in both the glass transition temperature and melting points (where applicable) of the ILs. Glass transition and melting occur well below room temperature. There is thus no conflict with the NMR and IR data, which show that the ILs are as mobile at room temperature as the bulk (not confined) ILs. The very narrow line widths of the NMR spectra suggest that the ILs in our materials have the highest mobility reported for confined ILs so far. As a result, our data suggest that it is possible to generate IL/silica hybrid materials (ionogels) with bulk-like properties of the IL. This could be interesting for applications in, e.g., the solar cell or membrane fields.
http://xlink.rsc.org/jumptojournal.cfm?journal_code=CP
10.1039/B821833a
1463-9076
allegro:1991-2014
10107997
Physical chemistry chemical physics. - ISSN 1463-9076. - 11 (2009), 19, S. 3653 - 3662
Ronald Goebel
Peter Hesemann
Jens Weber
Eléonore Moeller
Alwin Friedrich
Sabine Beuermann
Andreas Taubert
Institut für Chemie
Referiert
11956
2010
2010
eng
article
1
--
--
--
Transparent, flexible, and paramagnetic ionogels based on PMMA and the iron-based ionic liquid 1-butyl-3- methylimidazolium tetrachloroferrate(III) [Bmim][FeCl4]
The iron-containing ionic liquid (IL) 1-butyl-3-methylimidazolium tetrachloroferrate(III) [Bmim][FeCl4] has been used as a building block in the synthesis of transparent, ion-conducting, and paramagnetic ionogels. UV/Vis spectroscopy shows that the coordination around the Fe(III) ion does slightly change upon incorporation of the IL into PMMA. The thermal stability of the PMMA increases significantly with IL incorporation. In particular, the onset weight loss observed at ca. 265 degrees C for pure PMMA is completely suppressed. The ionic conductivity shows a strong temperature dependence and increases with increasing IL weight fractions. The magnetic properties are similar to those reported for the pure IL and are not affected by the incorporation into the PMMA matrix. The resulting ionogel is thus an interesting prototype for soft, flexible, and transparent materials combining the mechanical properties of the matrix with the functionality of the metal-containing IL, such as magnetism.
http://www.rsc.org/Publishing/Journals/jm/index.asp
10.1039/C0jm01733g
0959-9428
allegro:1991-2014
10107725
Journal of materials chemistry. - ISSN 0959-9428. - 20 (2010), 42, S. 9543-9549
Zai-Lai Xie
Aleksandra Jelicic
Feipeng Wang
Pierre Rabu
Alwin Friedrich
Sabine Beuermann
Andreas Taubert
Institut für Chemie
Referiert
36148
2012
2012
eng
791
795
5
2
4
article
American Chemical Society
Washington
1
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--
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CuO nanoparticles from the Strongly Hydrated Ionic Liquid Precursor (ILP) Tetrabutylammonium Hydroxide evaluation of the Ethanol Sensing Activity
The sensing potential of CuO nanoparticles synthesized via. precipitation from a water/ionic liquid precursor (ILP) mixture was investigated. The particles have a moderate surface area of 66 m(2)/g after synthesis, which decreases upon thermal treatment to below 5 m(2)/g. Transmission electron microscopy confirms crystal growth upon annealing, likely due to sintering effects. The as-synthesized particles can be used for ethanol sensing. The respective sensors show fast response and recovery times of below 10 s and responses greater than 2.3 at 100 ppm of ethanol at 200 degrees C, which is higher than any CuO-based ethanol sensor described so far.
ACS applied materials & interfaces
10.1021/am201427q
1944-8244
wos:2011-2013
WOS:000300644500043
Taubert, A (reprint author), Univ Potsdam, Inst Chem, D-14476 Potsdam, Germany., ataubert@uni-potsdam.de
Deutsche Forschungsgemeinschaft [TA571/2-1, 3-1, 7-1]; University of
Potsdam; MPI of Colloids and Interfaces (Colloid Chemistry Department)
Andreas Taubert
Franziska Stange
Zhonghao Li
Mathias Junginger
Christina Günter
Mike Neumann
Alwin Friedrich
eng
uncontrolled
ionic liquids
eng
uncontrolled
ionic liquid precursors
eng
uncontrolled
tetrabutylammonium hydroxide
eng
uncontrolled
nanoparticles
eng
uncontrolled
CuO
eng
uncontrolled
gas sensing
Institut für Chemie
Referiert
37287
2014
2014
eng
17579
17589
11
52
20
article
Wiley-VCH
Weinheim
1
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Modular thiol-ene chemistry approach towards mesoporous silica monoliths with organically modified pore walls
The surface modification of mesoporous silica monoliths through thiol-ene chemistry is reported. First, mesoporous silica monoliths with vinyl, allyl, and thiol groups were synthesized through a sol-gel hydrolysis-poly-condensation reaction from tetramethyl orthosilicate (TMOS) and vinyltriethoxysilane, allyltriethoxysilane, and (3-mercaptopropyl) trimethoxysilane, respectively. By variation of the molar ratio of the comonomers TMOS and functional silane, mesoporous silica objects containing different amounts of vinyl, allyl, and thiol groups were obtained. These intermediates can subsequently be derivatized through radical photoaddition reactions either with a thiol or an olefin, depending on the initial pore wall functionality, to yield silica monoliths with different pore-wall chemistries. Nitrogen sorption, small-angle X-ray scattering, solid-state NMR spectroscopy, elemental analysis, thermogravimetric analysis, and redox titration demonstrate that the synthetic pathway influences the morphology and pore characteristics of the resulting monoliths and also plays a significant role in the efficiency of functionalization. Moreover, the different reactivity of the vinyl and allyl groups on the pore wall affects the addition reaction, and hence, the degree of the pore-wall functionalization. This report demonstrates that thiol-ene photoaddition reactions are a versatile platform for the generation of a large variety of organically modified silica monoliths with different pore surfaces.
Chemistry - a European journal
10.1002/chem.201403982
25335454
0947-6539
1521-3765
wos:2014
WOS:000346468000038
Taubert, A (reprint author), Univ Potsdam, Inst Chem, Karl Liebknecht Str 24-25,Bldg 25, D-14476 Potsdam, Germany., ataubert@uni-potsdam.de
Potsdam Graduate School "Chemical Reaction in Green Solvents";
University of Potsdam; German Research Foundation [TA571/2-1,
TA571/3-1]; Max Planck Society
Ronald Goebel
Peter Hesemann
Alwin Friedrich
Regina Rothe
Helmut Schlaad
Andreas Taubert
eng
uncontrolled
mesoporous materials
eng
uncontrolled
photochemistry
eng
uncontrolled
sol-gel processes
eng
uncontrolled
surface chemistry
Institut für Chemie
Referiert