TY  - GEN
A1  - Jeličić, Aleksandra
A1  - Friedrich, Alwin
A1  - Jeremić, Katarina
A1  - Siekmeyer, Gerd
A1  - Taubert, Andreas
T1  - Polymer hydrogel/polybutadiene/iron oxide nanoparticle hybrid actuators for the characterization of NiTi implants
N2  - 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.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 161 
KW  - NiTi
KW  - inner surface
KW  - hydrogel
KW  - polybutadiene
KW  - magnetic nanoparticles
Y1  - 2009
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-48589
ER  - 
TY  - JOUR
A1  - Shkilnyy, Andriy
A1  - Gräf, Ralph
A1  - Hiebl, Bernhard
A1  - Neffe, Axel T.
A1  - Friedrich, Alwin
A1  - Hartmann, Juergen
A1  - Taubert, Andreas
T1  - Unprecedented, low cytotoxicity of spongelike calcium phosphate/poly(ethylene imine) hydrogel composites
N2  - 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.
Y1  - 2009
UR  - http://www3.interscience.wiley.com/cgi-bin/jhome/77002860
U6  - https://doi.org/10.1002/mabi.200800266
SN  - 1616-5187
ER  - 
TY  - JOUR
A1  - Goebel, Ronald
A1  - Hesemann, Peter
A1  - Weber, Jens
A1  - Moeller, Eléonore
A1  - Friedrich, Alwin
A1  - Beuermann, Sabine
A1  - Taubert, Andreas
T1  - Surprisingly high, bulk liquid-like mobility of silica-confined ionic liquids
N2  - 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.
Y1  - 2009
UR  - http://xlink.rsc.org/jumptojournal.cfm?journal_code=CP
U6  - https://doi.org/10.1039/B821833a
SN  - 1463-9076
ER  -