@book{Taubert2007, author = {Taubert, Andreas}, title = {Ionische Fl{\"u}ssigkeiten : chemische Kuriosa oder sind sie doch recht n{\"u}tzlich? ; Antrittsvorlesung 2007-05-24}, publisher = {Univ.-Bibl.}, address = {Potsdam}, year = {2007}, abstract = {Klassischerweise haben Salze, beispielsweise Kochsalz, Schmelzpunkte von einigen hundert Grad Celsius und mehr. Ionische Fl{\"u}ssigkeiten sind dagegen Salze, deren Schmelzpunkt zum Teil weit unter der Raumtemperatur liegt. Sie sind daher bei Raumtemperatur fl{\"u}ssig. Obwohl ionische Fl{\"u}ssigkeiten seit 1914 bekannt sind, hatten sie bis vor 15 Jahren keinerlei Bedeutung. Heute jedoch werden ionische Fl{\"u}ssigkeiten aufgrund ihrer vorteilhaften Eigenschaften, wie hohe Leitf{\"a}higkeit oder hohe Temperaturstabilit{\"a}t, unter anderem zur Papierverarbeitung oder in flexiblen Solarzellen eingesetzt. Die Antrittsvorlesung wird sich insbesondere mit der Herstellung anorganischer Partikel befassen und zeigen, wie ionische Fl{\"u}ssigkeiten zur Herstellung neuer Materialien f{\"u}r verschiedene Anwendungen genutzt werden k{\"o}nnen.}, language = {de} } @article{ShkilnyyGraefHiebletal.2009, author = {Shkilnyy, Andriy and Gr{\"a}f, Ralph and Hiebl, Bernhard and Neffe, Axel T. and Friedrich, Alwin and Hartmann, Juergen and Taubert, Andreas}, title = {Unprecedented, low cytotoxicity of spongelike calcium phosphate/poly(ethylene imine) hydrogel composites}, issn = {1616-5187}, doi = {10.1002/mabi.200800266}, year = {2009}, abstract = {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.}, language = {en} } @article{GoebelHesemannWeberetal.2009, author = {Goebel, Ronald and Hesemann, Peter and Weber, Jens and Moeller, El{\´e}onore and Friedrich, Alwin and Beuermann, Sabine and Taubert, Andreas}, title = {Surprisingly high, bulk liquid-like mobility of silica-confined ionic liquids}, issn = {1463-9076}, doi = {10.1039/B821833a}, year = {2009}, abstract = {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.}, language = {en} } @article{KindPlamperGoebeletal.2009, author = {Kind, Lucy and Plamper, Felix A. and Goebel, Ronald and Mantion, Alexandre and Mueller, Axel H. E. and Pieles, Uwe and Taubert, Andreas and Meier, Wolfgang P.}, title = {Silsesquioxane/polyamine nanoparticle-templated formation of star- or raspberry-like silica nanoparticles}, issn = {0743-7463}, doi = {10.1021/La900229n}, year = {2009}, abstract = {Silica is an important mineral in biology and technology, and many protocols have been developed for the synthesis of complex silica architectures. The current report shows that silsesquioxane nanoparticles carrying polymer arms on their surface are efficient templates for the fabrication of silica particles with a star- or raspberry-like morphology. The shape of the resulting particles depends on the chemistry of the polymer arms. With poly(N,N- dimethylaminoethyl methacrylate) (PDMAEMA) arms, spherical particles with a less electron dense core form. With poly {[2- (methacryloyloxy)ethyl] trimethylammonium iodide} (PMETAI), star- or raspberry-like particles form. Electron microscopy, electron tomography, and small-angle X-ray scattering show that the resulting silica particles have a complex structure, where a silsequioxane nanoparticle carrying the polymer arms is in the center. Next is a region that is polymer-rich. The outermost region of the particle is a silica layer, where the outer parts of the polymer arms are embedded. Time- resolved zeta-potential and pH measurements, dynamic light scattering, and electron microscopy reveal that silica formation proceeds differently if PDMAEMA is exchanged for PMETAI.}, language = {en} } @article{GrafMantionFoelskeetal.2009, author = {Graf, Philipp and Mantion, Alexandre and Foelske, Annette and Shkilnyy, Andriy and Ma{\"U}ic, Admir and Thuenemann, Andreas F. and Taubert, Andreas}, title = {Peptide-coated silver nanoparticles : synthesis, surface chemistry, and pH-triggered, reversible assembly into particle assemblies}, issn = {0947-6539}, doi = {10.1002/chem.200802329}, year = {2009}, abstract = {Simple tripeptides are scaffolds for the synthesis and further assembly of peptide/silver nanoparticle composites. Herein, we further explore peptide-con trolled silver nanoparticle assembly processes. Silver nanoparticles with a pH-responsive peptide coating have been synthesized by using a one-step precipitation/coating route. The nature of the peptide/silver interaction and the effect of the peptide oil the formation of the silver particles have been studied via UV/Vis, X-ray photoelectron, and surface-enhanced Raman spectroscopies as well as through electron microscopy, small angle X-ray scattering and powder Xray diffraction with Rietveld refinement. The particles reversibly form aggregates of different sizes in aqueous solution. The state of aggregation call be controlled by the solution pH value. At low pH values, individual particles are present. At neutral pH values, small clusters form and at high pH values, large precipitates are observed.}, language = {en} } @article{NavarroShkilnyyTierschetal.2009, author = {Navarro, Salvador and Shkilnyy, Andriy and Tiersch, Brigitte and Taubert, Andreas and Menzel, Henning}, title = {Preparation, characterization, and thermal gelation of amphiphilic alkyl-poly(ethyleneimine)}, issn = {0743-7463}, doi = {10.1021/La9013569}, year = {2009}, abstract = {Amphiphilic alkyl-poly(ethyleneimine)s (alkyl-PEI) with different degrees of polymerization have been produced by alkaline hydrolysis of alkyl-poly(2-methyl-2-oxazoline). Potentiometric titration of the alkyl-PEI shows the influence of the alkyl chain and the degree of polymerization on the titration curves and hence on the polymer conformation. Karl Fischer titration has been used to determine the water content in the polymers. Subsequent X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC) measurements prove the existence of different hydration states of the PEI even under dry storage conditions. Upon cooling from hot aqueous Solutions, hydrogels form. The gelation concentration decreases with increasing degree of polymerization of the PEI segment. Scanning electron microscopy (SEM and cryo-SEM) of the hydrogels reveal an alkyl-PEI fibrous network composed of fan-like units. DSC shows that the percentages of bound and free water in the hydrogels depend on the concentration of polar amino groups.}, language = {en} } @article{ShkilnyyBrandtMantionetal.2009, author = {Shkilnyy, Andriy and Brandt, Jessica and Mantion, Alexandre and Paris, Oskar and Schlaad, Helmut and Taubert, Andreas}, title = {Calcium phosphate with a channel-like morphology by polymer templating}, issn = {0897-4756}, doi = {10.1021/Cm803244z}, year = {2009}, abstract = {Calcium phosphate mineralization from aqueous solution in the presence of organic growth modifiers has been intensely studied in the recent past. This is mostly due to potential applications of the resulting composites in the biomaterials field. Polymers in particular are efficient growth modifiers. As a result, there has been a large amount of work on polymeric growth modifiers. Interestingly, however, relatively little work has been done on polycationic additives. The current paper shows that poly(ethylene oxide)b-poly(L-lysine) block copolymers lead to an interesting morphology of calcium phosphate precipitated at room temperature and subjected to a mild heat treatment at 85 degrees C. Electron microscopy, synchrotron X-ray diffraction, and porosity analysis show that a (somewhat) porous material with channel-like features forms. Closer inspection using transmission electron microscopy shows that the channels are probably not real channels. Much rather the morphology is the result of the aggregation of ca. 100-nm-sized rodlike primary particles, which changes upon drying to exhibit the observed channel-like features. Comparison experiments conducted in the absence of polymer and with poly(ethylene oxide)-b-poly(L-glutamate) show that these features only form in the presence of the polycationic poly(L-lysine) block, suggesting a distinct interaction of the polycation with either the crystal or the phosphate ions prior to mineralization.}, language = {en} } @misc{JeličićFriedrichJeremićetal.2009, author = {Jeličić, Aleksandra and Friedrich, Alwin and Jeremić, Katarina and Siekmeyer, Gerd and Taubert, Andreas}, title = {Polymer hydrogel/polybutadiene/iron oxide nanoparticle hybrid actuators for the characterization of NiTi implants}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-48589}, year = {2009}, abstract = {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.}, language = {en} } @misc{LiTaubert2009, author = {Li, Zhonghao and Taubert, Andreas}, title = {Cellulose/gold nanocrystal hybrids via an ionic liquid/aqueous precipitation route}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-45046}, year = {2009}, abstract = {Injection of a mixture of HAuCl4 and cellulose dissolved in the ionic liquid (IL) 1-butyl-3-methylimidazolium chloride [Bmim]Cl into aqueous NaBH4 leads to colloidal gold nanoparticle/cellulose hybrid precipitates. This process is a model example for a very simple and generic approach towards (noble) metal/cellulose hybrids, which could find applications in sensing, sterile filtration, or as biomaterials.}, language = {en} } @article{SchweizerSchusterJungingeretal.2010, author = {Schweizer, S. and Schuster, T. and Junginger, Matthias and Siekmeyer, Gerd and Taubert, Andreas}, title = {Surface modification of ickel/Titanium Alloy and Titanium Surfaces via a Polyelectrolyte Multilayer/Calcium Phosphate Hybrid Coating}, issn = {1438-7492}, doi = {10.1002/mame.200900347}, year = {2010}, abstract = {The report shows that simple LbL deposition of positively charged chitosan and negatively charged heparin can be used to efficiently modify the native surface of both NiTi and Ti without any previous treatments. Moreover, mineralization of the polymer multilayers with calcium phosphate leads to surfaces with low contact angles around 70 and 20 degrees for NiTi and Ti, respectively. This suggests that a polymer multilayer/calcium phosphate hybrid coating could be useful for making NiTi or Ti implants that are at the same time antibacterial (via the chitosan), suppress blood clot formation (via the heparin), and favor fast endothelialization (via the improved surface hydrophilicity compared to the respective neat material).}, language = {en} } @article{AyiKhareStrauchetal.2010, author = {Ayi, Ayi A. and Khare, Varsha and Strauch, Peter and Girard, J{\`e}r{\^o}me and Fromm, Katharina M. and Taubert, Andreas}, title = {On the chemical synthesis of titanium nanoparticles from ionic liquids}, issn = {0026-9247}, doi = {10.1007/s00706-010-0403-4}, year = {2010}, abstract = {We report on attempts towards the synthesis of titanium nanoparticles using a wet chemical approach in imidazolium-based ionic liquids (ILs) under reducing conditions. Transmission electron microscopy finds nanoparticles in all cases. UV/Vis spectroscopy confirms the nanoparticulate nature of the precipitate, as in all cases an absorption band between ca. 280 and 300 nm is visible. IR spectroscopy shows that even after extensive washing and drying, some IL remains adsorbed on the nanoparticles. Raman spectroscopy suggests the formation of anatase nanoparticles, but X-ray diffraction reveals that, possibly, amorphous titania forms or that the nanoparticles are so small that a clear structure assignment is not possible. The report thus shows that (possibly amorphous) titanium oxides even form under reducing conditions and that the chemical synthesis of titanium nanoparticles in ILs remains elusive.}, language = {en} } @article{XieJelicicWangetal.2010, author = {Xie, Zai-Lai and Jelicic, Aleksandra and Wang, Feipeng and Rabu, Pierre and Friedrich, Alwin and Beuermann, Sabine and Taubert, Andreas}, title = {Transparent, flexible, and paramagnetic ionogels based on PMMA and the iron-based ionic liquid 1-butyl-3- methylimidazolium tetrachloroferrate(III) [Bmim][FeCl4]}, issn = {0959-9428}, doi = {10.1039/C0jm01733g}, year = {2010}, abstract = {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.}, language = {en} } @misc{KitaTokarczykJungingerBelegrinouetal.2011, author = {Kita-Tokarczyk, Katarzyna and Junginger, Mathias and Belegrinou, Serena and Taubert, Andreas}, title = {Amphiphilic polymers at interfaces}, series = {Advances in polymer science}, volume = {242}, journal = {Advances in polymer science}, number = {1}, editor = {Muller, AHE and Borisov, O}, publisher = {Springer}, address = {Berlin}, isbn = {978-3-642-22297-9}, issn = {0065-3195}, doi = {10.1007/12_2010_58}, pages = {151 -- 201}, year = {2011}, abstract = {Self-assembly phenomena in block copolymer systems are attracting considerable interest from the scientific community and industry alike. Particularly interesting is the behavior of amphiphilic copolymers, which can self-organize into nanoscale-sized objects such as micelles, vesicles, or tubes in solution, and which form well-defined assemblies at interfaces such as air-liquid, air-solid, or liquid-solid. Depending on the polymer chemistry and architecture, various types of organization at interfaces can be expected, and further exploited for applications in nanotechnology, electronics, and biomedical sciences. In this article, we discuss the formation and characterization of Langmuir monolayers from various amphiphilic block copolymers, including chargeable and thus pH-responsivematerials. Solid-supported polymer films are reviewed in the context of alteration of surface properties by ultrathin polymer layers and the possibilities for application in tissue engineering, sensors and biomaterials. Finally, we focus on how organic and polymer monolayers influence the growth of inorganic materials. This is a truly biomimetic approach since Nature uses soft interfaces to control the nucleation, growth, and morphology of biominerals such as calcium phosphate, calcium carbonate, and silica.}, language = {en} } @article{YuantenBrummelhuisJungingeretal.2011, author = {Yuan, Jiayin and ten Brummelhuis, Niels and Junginger, Mathias and Xie, Zailai and Lu, Yan and Taubert, Andreas and Schlaad, Helmut}, title = {Diversified applications of chemically modified 1,2-Polybutadiene}, series = {Macromolecular rapid communications}, volume = {32}, journal = {Macromolecular rapid communications}, number = {15}, publisher = {Wiley-Blackwell}, address = {Malden}, issn = {1022-1336}, doi = {10.1002/marc.201100254}, pages = {1157 -- 1162}, year = {2011}, abstract = {Commercially available 1,2-PB was transformed into a well-defined reactive intermediate by quantitative bromination. The brominated polymer was used as a polyfunctional macroinitiator for the cationic ring-opening polymerization of 2-ethyl-2-oxazoline to yield a water-soluble brush polymer. Nucleophilic substitution of bromide by 1-methyl imidazole resulted in the formation of polyelectrolyte copolymers consisting of mixed units of imidazolium, bromo, and double bond. These copolymers, which were soluble in water without forming aggregates, were used as stabilizers in the heterophase polymerization of styrene and were also studied for their ionic conducting properties.}, language = {en} } @article{HaaseArlinghausTentschertetal.2011, author = {Haase, Andrea and Arlinghaus, Heinrich F. and Tentschert, Jutta and Jungnickel, Harald and Graf, Philipp and Mantion, Alexandre and Draude, Felix and Galla, Sebastian and Plendl, Johanna and Goetz, Mario E. and Masic, Admir and Meier, Wolfgang P. and Thuenemann, Andreas F. and Taubert, Andreas and Luch, Andreas}, title = {Application of Laser Postionization Secondary Neutral Mass Spectrometry/Time-of-Flight Secondary Ion Mass Spectrometry in Nanotoxicology: Visualization of Nanosilver in Human Macrophages and Cellular Responses}, series = {ACS nano}, volume = {5}, journal = {ACS nano}, number = {4}, publisher = {American Chemical Society}, address = {Washington}, issn = {1936-0851}, doi = {10.1021/nn200163w}, pages = {3059 -- 3068}, year = {2011}, abstract = {Silver nanoparticles (SNP) are the subject of worldwide commercialization because of their antimicrobial effects. Yet only little data on their mode of action exist. Further, only few techniques allow for visualization and quantification of unlabeled nanoparticles inside cells. To study SNP of different sizes and coatings within human macrophages, we introduce a novel laser postionization secondary neutral mass spectrometry (Laser-SNMS) approach and prove this method superior to the widely applied confocal Raman and transmission electron microscopy. With time-of-flight secondary ion mass spectrometry (TOF-SIMS) we further demonstrate characteristic fingerprints in the lipid pattern of the cellular membrane indicative of oxidative stress and membrane fluidity changes. Increases of protein carbonyl and heme oxygenase-1 levels in treated cells confirm the presence of oxidative stress biochemically. Intriguingly, affected phagocytosis reveals as highly sensitive end point of SNP-mediated adversity In macrophages. The cellular responses monitored are. hierarchically linked, but follow individual kinetics and are partially reversible.}, language = {en} } @article{PrietoShkilnyyRumplaschetal.2011, author = {Prieto, Susana and Shkilnyy, Andriy and Rumplasch, Claudia and Ribeiro, Artur and Javier Arias, F. and Carlos Rodriguez-Cabello, Jose and Taubert, Andreas}, title = {Biomimetic calcium phosphate mineralization with multifunctional elastin-like recombinamers}, series = {Biomacromolecules : an interdisciplinary journal focused at the interface of polymer science and the biological sciences}, volume = {12}, journal = {Biomacromolecules : an interdisciplinary journal focused at the interface of polymer science and the biological sciences}, number = {5}, publisher = {American Chemical Society}, address = {Washington}, issn = {1525-7797}, doi = {10.1021/bm200287c}, pages = {1480 -- 1486}, year = {2011}, abstract = {Biomimetic hybrid materials based on a polymeric and an inorganic component such as calcium phosphate are potentially useful for bone repair. The current study reports on a new approach toward biomimetic hybrid materials using a set of recombinamers (recombinant protein materials obtained from a synthetic gene) as crystallization additive for calcium phosphate. The recombinamers contain elements from elastin, an elastic structural protein, and statherin, a salivary protein. Via genetic engineering, the basic elastin sequence was modified with the SN(A)15 domain of statherin, whose interaction with calcium phosphate is well-established. These new materials retain the biocompatibility, "smart" nature, and desired mechanical behavior of the elastin-like recombinamer (ELR) family. Mineralization in simulated body fluid (SBF) in the presence of these recombinamers reveals surprising differences. Two of the polymers inhibit calcium phosphate deposition (although they contain the statherin segment). In contrast, the third polymer, which has a triblock structure, efficiently controls the calcium phosphate formation, yielding spherical hydroxyapatite (HAP) nanoparticles with diameters from 1 to 3 nm after 1 week in SBF at 37 degrees C. However, at lower temperatures, no precipitation is observed with any of the polymers. The data thus suggest that the molecular design of ELRs containing statherin segments and the selection of an appropriate polymer structure are key parameters to obtain functional materials for the development of intelligent systems for hard tissue engineering and subsequent in vivo applications.}, language = {en} } @article{FarraThielWinteretal.2011, author = {Farra, Ramzi and Thiel, Kerstin and Winter, Alette and Klamroth, Tillmann and Poeppl, Andreas and Kelling, Alexandra and Schilde, Uwe and Taubert, Andreas and Strauch, Peter}, title = {Tetrahalidocuprates(II)-structure and EPR spectroscopy Part 1: Tetrabromidocuprates(II)}, series = {New journal of chemistry}, volume = {35}, journal = {New journal of chemistry}, number = {12}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1144-0546}, doi = {10.1039/c1nj20271e}, pages = {2793 -- 2803}, year = {2011}, abstract = {Tetrahalidocuprates(II) show a high degree of structural flexibility. We present the results of crystallographic and electron paramagnetic resonance (EPR) spectroscopic analyses of four new tetrabromidocuprate(II) compounds and compare the results with previously reported data. The cations in the new compounds are the sterically demanding benzyltriphenylphosphonium, methyltriphenylphosphonium, tetraphenylphosphonium, and hexadecyltrimethylammonium ions; they were used to achieve a reasonable separation of the paramagnetic Cu(II) ions for EPR spectroscopy. X-Ray crystallography shows that in all four complexes the [CuBr4](2-) units have a distorted tetrahedral coordination geometry which is in agreement with DFT calculations. The EPR hyperfine structure was not resolved. This is due to the exchange broadening resulting from still incomplete separation of the paramagnetic Cu(II) centres. Nevertheless, the principal values of the electron Zeemann tensor (g(parallel to) and g(perpendicular to)) of the complexes could be determined. A correlation of structural (X-ray) parameters with the spin density at the copper centres (DFT) is well reflected in the EPR spectra of the bromidocuprates. This enables the correlation of X-ray and EPR parameters to predict the structure of tetrabromidocuprates in physical states other than the crystalline state. As a result, we provide a method to structurally characterize [CuBr4](2-) in, for example, ionic liquids or in solution, which has important implications for e.g. catalysis or materials science.}, language = {en} } @article{GrafMantionHaaseetal.2011, author = {Graf, Philipp and Mantion, Alexandre and Haase, Andrea and Thuenemann, Andreas F. and Masic, Admir and Meier, Wolfgang P. and Luch, Andreas and Taubert, Andreas}, title = {Silicification of peptide-coated silver nanoparticles-A biomimetic soft chemistry approach toward chiral hybrid core-shell materials}, series = {ACS nano}, volume = {5}, journal = {ACS nano}, number = {2}, publisher = {American Chemical Society}, address = {Washington}, issn = {1936-0851}, doi = {10.1021/nn102969p}, pages = {820 -- 833}, year = {2011}, abstract = {Silica and silver nanoparticles are relevant materials for new applications in optics, medicine, and analytical chemistry. We have previously reported the synthesis of pH responsive, peptide-templated, chiral silver nanoparticles. The current report shows that peptide-stabilized nanoparticles can easily be coated with a silica shell by exploiting the ability of the peptide coating to hydrolyze silica precursors such as TEOS or TMOS. The resulting silica layer protects the nanoparticles from chemical etching, allows their inclusion in other materials, and renders them biocompatible. Using electron and atomic force microscopy, we show that the silica shell thickness and the particle aggregation can be controlled simply by the reaction time. Small-angle X ray scattering confirms the Ag/peptide@silica core-shell structure. UV-vis and circular dichroism spectroscopy prove the conservation of the silver nanoparticle chirality upon silicification. Biological tests show that the biocompatibility in simple bacterial systems is significantly improved once a silica layer is deposited on the silver particles.}, language = {en} } @article{XieTaubert2011, author = {Xie, Zai-Lai and Taubert, Andreas}, title = {Thermomorphic behavior of the ionic liquids [C(4)mim][FeCl4] and [C(12)mim][FeCl4]}, series = {ChemPhysChem : a European journal of chemical physics and physical chemistry}, volume = {12}, journal = {ChemPhysChem : a European journal of chemical physics and physical chemistry}, number = {2}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1439-4235}, doi = {10.1002/cphc.201000808}, pages = {364 -- 368}, year = {2011}, abstract = {The iron-containing ionic liquids 1-butyl-3-methylimidazolium tetrachloroferrate(III) [C(4)mim][FeCl4] and 1-dodecyl-3-methylimidazolium tetrachloroferrate(III) [C(12)mim][FeCl4] exhibit a thermally induced demixing with water (thermomorphism). The phase separation temperature varies with IL weight fraction in water and can be tuned between 100 degrees C and room temperature. The reversible lower critical solution temperature (LCST) is only observed at IL weight fractions below ca. 35\% in water. UV/Vis, IR, and Raman spectroscopy along with elemental analysis prove that the yellow-brown liquid phase recovered after phase separation is the starting IL [C(4)mim][FeCl4] and [C(12)mim][FeCl4], respectively. Photometry and ICP-OES show that about 40\% of iron remains in the water phase upon phase separation. Although the process is thus not very efficient at the moment, the current approach is the first example of an LCST behavior of a metal-containing IL and therefore, although still inefficient, a prototype for catalyst removal or metal extraction.}, language = {en} } @article{MarquardtXieTaubertetal.2011, author = {Marquardt, Dorothea and Xie, Zailai and Taubert, Andreas and Thomann, Ralf and Janiak, Christoph}, title = {Microwave synthesis and inherent stabilization of metal nanoparticles in 1-methyl-3-(3-carboxyethyl)-imidazolium tetrafluoroborate}, series = {Dalton transactions : a journal of inorganic chemistry, including bioinorganic, organometallic, and solid-state chemistry}, volume = {40}, journal = {Dalton transactions : a journal of inorganic chemistry, including bioinorganic, organometallic, and solid-state chemistry}, number = {33}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1477-9226}, doi = {10.1039/c1dt10795j}, pages = {8290 -- 8293}, year = {2011}, abstract = {The synthesis of Co-NPs and Mn-NPs by microwave-induced decomposition of the metal carbonyls Co-2(CO)(8) and Mn-2(CO)(10), respectively, yields smaller and better separated particles in the functionalized IL 1-methyl-3-(3-carboxyethyl)-imidazolium tetrafluoroborate [EmimCO(2)H][BF4] (1.6 +/- 0.3 nm and 4.3 +/- 1.0 nm, respectively) than in the non-functionalized IL 1-n-butyl-3-methylimidazolium tetrafluoroborate [Bmim][BF4]. The particles are stable in the absence of capping ligands (surfactants) for more than six months although some variation in particle size could be observed by TEM.}, language = {en} } @article{MantionGrafFloreaetal.2011, author = {Mantion, Alexandre and Graf, Philipp and Florea, Ileana and Haase, Andrea and Thuenemann, Andreas F. and Masic, Admir and Ersen, Ovidiu and Rabu, Pierre and Meier, Wolfgang P. and Luch, Andreas and Taubert, Andreas}, title = {Biomimetic synthesis of chiral erbium-doped silver/peptide/silica core-shell nanoparticles (ESPN)}, series = {Nanoscale}, volume = {3}, journal = {Nanoscale}, number = {12}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {2040-3364}, doi = {10.1039/c1nr10930h}, pages = {5168 -- 5179}, year = {2011}, abstract = {Peptide-modified silver nanoparticles have been coated with an erbium-doped silica layer using a method inspired by silica biomineralization. Electron microscopy and small-angle X-ray scattering confirm the presence of an Ag/peptide core and silica shell. The erbium is present as small Er(2)O(3) particles in and on the silica shell. Raman, IR, UV-Vis, and circular dichroism spectroscopies show that the peptide is still present after shell formation and the nanoparticles conserve a chiral plasmon resonance. Magnetic measurements find a paramagnetic behavior. In vitro tests using a macrophage cell line model show that the resulting multicomponent nanoparticles have a low toxicity for macrophages, even on partial dissolution of the silica shell.}, language = {en} } @article{XieWhiteWeberetal.2011, author = {Xie, Zai-Lai and White, Robin J. and Weber, Jens and Taubert, Andreas and Titirici, Magdalena M.}, title = {Hierarchical porous carbonaceous materials via ionothermal carbonization of carbohydrates}, series = {Journal of materials chemistry}, volume = {21}, journal = {Journal of materials chemistry}, number = {20}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {0959-9428}, doi = {10.1039/c1jm00013f}, pages = {7434 -- 7442}, year = {2011}, abstract = {We report on the ionothermal synthesis of porous carbon materials from a variety of carbohydrate precursors (i.e. D-glucose, D-fructose, D-xylose, and starch) using 1-butyl-3-methylimidazolium tetrachloroferrate(III), [Bmim][FeCl(4)] as a reusable solvent and catalyst. The carbon materials derived from these different carbohydrates are similar in terms of particle size and chemical composition, possessing relatively high surface areas from 44 to 155 m(2) g(-1) after ionothermal processing, which can be significantly increased to > 350 m(2) g(-1) by further thermal treatment (e. g. post-carbonization at 750 degrees C). CO(2) and N(2) sorption analysis, combined with Hg intrusion porosimetry, reveals a promising hierarchical pore structuring to these carbon materials. The ionic liquid [Bmim][FeCl(4)] has a triple role: it acts as both a soft template to generate the characterized pore structuring, solvent and as a catalyst resulting in enhanced ionothermal carbon yields. Importantly from a process point of view, the ionic liquid can be successfully recovered and reused. The current work shows that ionothermal synthesis has the potential to be an effective, low cost, and green reusable synthetic route towards sustainable porous carbon materials.}, language = {en} } @article{DouceSuisseGuillonetal.2011, author = {Douce, Laurent and Suisse, Jean-Moise and Guillon, Daniel and Taubert, Andreas}, title = {Imidazolium-based liquid crystals a modular platform for versatile new materials with finely tuneable properties and behaviour}, series = {Liquid crystals : an international journal of science and technology}, volume = {38}, journal = {Liquid crystals : an international journal of science and technology}, number = {11-12}, publisher = {Routledge, Taylor \& Francis Group}, address = {Abingdon}, issn = {0267-8292}, doi = {10.1080/02678292.2011.610474}, pages = {1653 -- 1661}, year = {2011}, abstract = {Ionic liquid Crystals constitute highly versatile materials that have drawn much interest these past few years in the fields of academic research and industrial development. In this respect, the present article is intended as an update of K. Binnemans review published in 2005, but focusing exclusively on the imidazolium cation - the most widely studied. Herein, imidazolium-containing thermotropic liquid crystalline materials will be sorted by molecular structure (mono-, bis-, poly-imidazolium compounds, with symmetrical and non-symmetrical structures) and discussed. Their physico-chemical properties will be exposed in order to adduce the relevancy and potential of the imidazolium platform in various fields of research.}, language = {en} } @article{ThielKlamrothStrauchetal.2011, author = {Thiel, Kerstin and Klamroth, Tillmann and Strauch, Peter and Taubert, Andreas}, title = {On the interaction of ascorbic acid and the tetrachlorocuprate ion [CuCl4](2-) in CuCl nanoplatelet formation from an ionic liquid precursor (ILP)}, series = {Physical chemistry, chemical physics : a journal of European Chemical Societies}, volume = {13}, journal = {Physical chemistry, chemical physics : a journal of European Chemical Societies}, number = {30}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1463-9076}, doi = {10.1039/c1cp20648f}, pages = {13537 -- 13543}, year = {2011}, abstract = {The formation of CuCl nanoplatelets from the ionic liquid precursor (ILP) butylpyridinium tetrachlorocuprate [C4Py](2)[CuCl4] using ascorbic acid as a reducing agent was investigated. In particular, electron paramagnetic resonance (EPR) spectroscopy was used to evaluate the interaction between ascorbic acid and the Cu(II) ion before reduction to Cu(I). EPR spectroscopy suggests that the [CuCl4](2-) ion in the neat IL is a distorted tetrahedron, consistent with DFT calculations. Addition of ascorbic acid leads to the removal of one chloride from the [CuCl4](2-) anion, as shown by DFT and the loss of symmetry by EPR. DFT furthermore suggests that the most stable adduct is formed when only one hydroxyl group of the ascorbic acid coordinates to the Cu(II) ion.}, language = {en} } @article{LoebbickeChananaSchlaadetal.2011, author = {L{\"o}bbicke, Ruben and Chanana, Munish and Schlaad, Helmut and Pilz-Allen, Christine and G{\"u}nter, Christina and M{\"o}hwald, Helmuth and Taubert, Andreas}, title = {Polymer Brush Controlled Bioinspired Calcium Phosphate Mineralization and Bone Cell Growth}, series = {Biomacromolecules : an interdisciplinary journal focused at the interface of polymer science and the biological sciences}, volume = {12}, journal = {Biomacromolecules : an interdisciplinary journal focused at the interface of polymer science and the biological sciences}, number = {10}, publisher = {American Chemical Society}, address = {Washington}, issn = {1525-7797}, doi = {10.1021/bm200991b}, pages = {3753 -- 3760}, year = {2011}, abstract = {Polymer brushes on thiol-modified gold surfaces were synthesized by using terminal thiol groups for the surface initiated free radical polymerization of methacrylic acid and dimethylaminotheyl methacrylate, respectively. Atomic force microscopy shows that the resulting poly(methacrylic acid (PMAA) and poly(dimethylaminothyl methacrylate) (PDM- AEMA) brushes are homogeneous. Contact angle measurements show that the brushes are pH responsive and can reversibly be protonated and deprotonated. Mineralization of the brushes with calcium phosphate at different pH yields homogeneously mineralized surfaces, and preosteoblastic cells proliferate-on be number of living cells on the mineralized hybrid surface is ca. 3 times (P corresponding nonmineralized brushes.}, language = {en} } @article{DelahayeXieSchaeferetal.2011, author = {Delahaye, Emilie and Xie, Zailai and Sch{\"a}fer, Andreas and Douce, Laurent and Rogez, Guillaume and Rabu, Pierre and G{\"u}nter, Christina and Gutmann, Jochen S. and Taubert, Andreas}, title = {Intercalation synthesis of functional hybrid materials based on layered simple hydroxide hosts and ionic liquid guests - a pathway towards multifunctional ionogels without a silica matrix?}, series = {Dalton transactions : a journal of inorganic chemistry, including bioinorganic, organometallic, and solid-state chemistry}, volume = {40}, journal = {Dalton transactions : a journal of inorganic chemistry, including bioinorganic, organometallic, and solid-state chemistry}, number = {39}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1477-9226}, doi = {10.1039/c1dt10841g}, pages = {9977 -- 9988}, year = {2011}, abstract = {Functional hybrid materials on the basis of inorganic hosts and ionic liquids (ILs) as guests hold promise for a virtually unlimited number of applications. In particular, the interaction and the combination of properties of a defined inorganic matrix and a specific IL could lead to synergistic effects in property selection and tuning. Such hybrid materials, generally termed ionogels, are thus an emerging topic in hybrid materials research. The current article addresses some of the recent developments and focuses on the question why silica is currently the dominating matrix used for (inorganic) ionogel fabrication. In comparison to silica, matrix materials such as layered simple hydroxides, layered double hydroxides, clay-type substances, magnetic or catalytically active solids, and many other compounds could be much more interesting because they themselves may carry useful functionalities, which could also be exploited for multifunctional hybrid materials synthesis. The current article combines experimental results with some arguments as to how new, advanced functional hybrid materials can be generated and which obstacles will need to be overcome to successfully achieve the synthesis of a desired target material.}, language = {en} } @article{ShkilnyySchoeneRumplaschetal.2011, author = {Shkilnyy, Andriy and Sch{\"o}ne, Stefanie and Rumplasch, Claudia and Uhlmann, Annett and Hedderich, Annett and G{\"u}nter, Christina and Taubert, Andreas}, title = {Calcium phosphate mineralization with linear poly(ethylene imine) a time-resolved study}, series = {Colloid and polymer science : official journal of the Kolloid-Gesellschaft}, volume = {289}, journal = {Colloid and polymer science : official journal of the Kolloid-Gesellschaft}, number = {8}, publisher = {Springer}, address = {New York}, issn = {0303-402X}, doi = {10.1007/s00396-011-2403-2}, pages = {881 -- 888}, year = {2011}, abstract = {We have earlier shown that linear poly(ethylene imine) (LPEI) is an efficient growth modifier for calcium phosphate mineralization from aqueous solution (Shkilnyy et al., Langmuir, 2008, 24 (5), 2102). The current study addresses the growth process and the reason why LPEI is such an effective additive. To that end, the solution pH and the calcium and phosphate concentrations were monitored vs. reaction time using potentiometric, complexometric, and photometric methods. The phase transformations in the precipitates and particle morphogenesis were analyzed by X-ray diffraction and transmission electron microscopy, respectively. All measurements reveal steep decreases of the pH, calcium, and phosphate concentrations along with a rapid precipitation of brushite nanoparticles early on in the reaction. Brushite transforms into hydroxyapatite (HAP) within the first 2 h, which is much faster than what is reported, for example, for calcium phosphate precipitated with poly(acrylic acid). We propose that poly(ethylene imine) acts as a proton acceptor (weak buffer), which accelerates the transformation from brushite to HAP by taking up the protons that are released from the calcium phosphate precipitate during the phase transformation.}, language = {en} } @article{HaaseRottMantionetal.2012, author = {Haase, Andrea and Rott, Stephanie and Mantion, Alexandre and Graf, Philipp and Plendl, Johanna and Th{\"u}nemann, Andreas F. and Meier, Wolfgang P. and Taubert, Andreas and Luch, Andreas and Reiser, Georg}, title = {Effects of silver nanoparticles on primary mixed neural cell cultures: Uptake, oxidative stress and acute calcium responses}, series = {Toxicological sciences}, volume = {126}, journal = {Toxicological sciences}, number = {2}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {1096-6080}, doi = {10.1093/toxsci/kfs003}, pages = {457 -- 468}, year = {2012}, abstract = {In the body, nanoparticles can be systemically distributed and then may affect secondary target organs, such as the central nervous system (CNS). Putative adverse effects on the CNS are rarely investigated to date. Here, we used a mixed primary cell model consisting mainly of neurons and astrocytes and a minor proportion of oligodendrocytes to analyze the effects of well-characterized 20 and 40 nm silver nanoparticles (SNP). Similar gold nanoparticles served as control and proved inert for all endpoints tested. SNP induced a strong size-dependent cytotoxicity. Additionally, in the low concentration range (up to 10 mu g/ml of SNP), the further differentiated cultures were more sensitive to SNP treatment. For detailed studies, we used low/medium dose concentrations (up to 20 mu g/ml) and found strong oxidative stress responses. Reactive oxygen species (ROS) were detected along with the formation of protein carbonyls and the induction of heme oxygenase-1. We observed an acute calcium response, which clearly preceded oxidative stress responses. ROS formation was reduced by antioxidants, whereas the calcium response could not be alleviated by antioxidants. Finally, we looked into the responses of neurons and astrocytes separately. Astrocytes were much more vulnerable to SNP treatment compared with neurons. Consistently, SNP were mainly taken up by astrocytes and not by neurons. Immunofluorescence studies of mixed cell cultures indicated stronger effects on astrocyte morphology. Altogether, we can demonstrate strong effects of SNP associated with calcium dysregulation and ROS formation in primary neural cells, which were detectable already at moderate dosages.}, language = {en} } @article{HaaseMantionGrafetal.2012, author = {Haase, A. and Mantion, A. and Graf, P. and Plendl, J. and Th{\"u}nemann, Andreas F. and Meier, Wolfgang P. and Taubert, Andreas and Luch, A.}, title = {A novel type of silver nanoparticles and their advantages in toxicity testing in cell culture systems}, series = {Archives of toxicology : official journal of EUROTOX}, volume = {86}, journal = {Archives of toxicology : official journal of EUROTOX}, number = {7}, publisher = {Springer}, address = {Heidelberg}, issn = {0340-5761}, doi = {10.1007/s00204-012-0836-0}, pages = {1089 -- 1098}, year = {2012}, abstract = {Silver nanoparticles (SNPs) are among the most commercialized nanoparticles worldwide. Often SNP are used because of their antibacterial properties. Besides that they possess unique optic and catalytic features, making them highly interesting for the creation of novel and advanced functional materials. Despite its widespread use only little data exist in terms of possible adverse effects of SNP on human health. Conventional synthesis routes usually yield products of varying quality and property. It thus may become puzzling to compare biological data from different studies due to the great variety in sizes, coatings or shapes of the particles applied. Here, we applied a novel synthesis approach to obtain SNP of well-defined colloidal and structural properties. Being stabilized by a covalently linked small peptide, these particles are nicely homogenous, with narrow size distribution, and form monodisperse suspensions in aqueous solutions. We applied these peptide-coated SNP in two different sizes of 20 or 40 nm (Ag20Pep and Ag40Pep) and analyzed responses of THP-1-derived human macrophages while being exposed against these particles. Gold nanoparticles of similar size and coating (Au20Pep) were used for comparison. The cytotoxicity of particles was assessed by WST-1 and LDH assays, and the uptake into the cells was confirmed via transmission electron microscopy. In summary, our data demonstrate that this novel type of SNP is well suited to serve as model system for nanoparticles to be tested in toxicological studies in vitro.}, language = {en} } @article{CasseShkilnyyLindersetal.2012, author = {Casse, Olivier and Shkilnyy, Andriy and Linders, J{\"u}rgen and Mayer, Christian and H{\"a}ussinger, Daniel and V{\"o}lkel, Antje and Th{\"u}nemann, Andreas F. and Dimova, Rumiana and C{\"o}lfen, Helmut and Meier, Wolfgang P. and Schlaad, Helmut and Taubert, Andreas}, title = {Solution behavior of double-hydrophilic block copolymers in dilute aqueous solution}, series = {Macromolecules : a publication of the American Chemical Society}, volume = {45}, journal = {Macromolecules : a publication of the American Chemical Society}, number = {11}, publisher = {American Chemical Society}, address = {Washington}, issn = {0024-9297}, doi = {10.1021/ma300621g}, pages = {4772 -- 4777}, year = {2012}, abstract = {The self-assembly of double-hydrophilic poly(ethylene oxide)-poly(2-methyl-2-oxazoline) diblock copolymers in water has been studied. Isothermal titration calorimetry, small-angle X-ray scattering, and analytical ultracentrifugation suggest that only single polymer chains are present in solution. In contrast, light scattering and transmission electron microscopy detect aggregates with radii of ca. 100 nm. Pulsed field gradient NMR spectroscopy confirms the presence of aggregates, although only 2\% of the polymer chains undergo aggregation. Water uptake experiments indicate differences in the hydrophilicity of the two blocks, which is believed to be the origin of the unexpected aggregation behavior (in accordance with an earlier study by Ke et al. [Macromolecules 2009, 42, 5339-5344]). The data therefore suggest that even in double-hydrophilic block copolymers, differences in hydrophilicity are sufficient to drive polymer aggregation, a phenomenon that has largely been overlooked or ignored so far.}, language = {en} } @article{ZiolkowskiBleekTwamleyetal.2012, author = {Ziolkowski, Bartosz and Bleek, Katrin and Twamley, Brendan and Fraser, Kevin J. and Byrne, Robert and Diamond, Dermot and Taubert, Andreas}, title = {Magnetic ionogels (MagIGs) based on iron oxide nanoparticles, poly(N-isopropylacrylamide), and the ionic liquid trihexyl(tetradecyl)phosphonium dicyanamide}, series = {European journal of inorganic chemistry : a journal of ChemPubSoc Europe}, journal = {European journal of inorganic chemistry : a journal of ChemPubSoc Europe}, number = {32}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1434-1948}, doi = {10.1002/ejic.201200597}, pages = {5245 -- 5251}, year = {2012}, abstract = {Magnetic ionogels (MagIGs) were prepared from organosilane-coated iron oxide nanoparticles, N-isopropylacrylamide, and the ionic liquid trihexyl(tetradecyl)phosphonium dicyanamide. The ionogels prepared with the silane-modified nanoparticles are more homogeneous than ionogels prepared with unmodified magnetite particles. The silane-modified particles are immobilized in the ionogel and are resistant tonanoparticle leaching. The modified particles also render the ionogels mechanically more stable than the ionogels synthesized with unmodified nanoparticles. The ionogels respond to external permanent magnets and are therefore prototypes of a new soft magnetic actuator.}, language = {en} } @unpublished{BuehlerRabuTaubert2012, author = {B{\"u}hler, Markus J. and Rabu, Pierre and Taubert, Andreas}, title = {Advanced hybrid materials - design and applications}, series = {European journal of inorganic chemistry : a journal of ChemPubSoc Europe}, journal = {European journal of inorganic chemistry : a journal of ChemPubSoc Europe}, number = {32}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1434-1948}, doi = {10.1002/ejic.201201263}, pages = {5092 -- 5093}, year = {2012}, language = {en} } @article{XieXuGessneretal.2012, author = {Xie, Zai-Lai and Xu, Hai-Bing and Gessner, Andre and Kumke, Michael Uwe and Priebe, Magdalena and Fromm, Katharina M. and Taubert, Andreas}, title = {A transparent, flexible, ion conductive, and luminescent PMMA ionogel based on a Pt/Eu bimetallic complex and the ionic liquid [Bmim][N(Tf)(2)]}, series = {Journal of materials chemistry}, volume = {22}, journal = {Journal of materials chemistry}, number = {16}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {0959-9428}, doi = {10.1039/c2jm15862k}, pages = {8110 -- 8116}, year = {2012}, abstract = {Transparent, ion-conducting, luminescent, and flexible ionogels based on the room temperature ionic liquid (IL) 1-butyl-3-methylimidazolium bis(trifluoromethane sulfonyl) imide [Bmim][N(Tf)(2)], a PtEu2 chromophore, and poly(methylmethacrylate) (PMMA) have been prepared. The thermal stability of the PMMA significantly increases with IL incorporation. In particular, the onset weight loss observed at ca. 229 degrees C for pure PMMA increases to 305 degrees C with IL addition. The ionogel has a high ionic conductivity of 10(-3) S cm(-1) at 373 K and exhibits a strong emission in the red with a long average luminescence decay time of tau = 890 mu s. The resulting material is a new type of soft hybrid material featuring useful thermal, optical, and ion transport properties.}, language = {en} } @article{SiTaubertMantionetal.2012, author = {Si, Satyabrata and Taubert, Andreas and Mantion, Alexandre and Rogez, Guillaume and Rabu, Pierre}, title = {Peptide-intercalated layered metal hydroxides effect of peptide chain length and side chain functionality on structural, optical and magnetic properties}, series = {Chemical science}, volume = {3}, journal = {Chemical science}, number = {6}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {2041-6520}, doi = {10.1039/c2sc01087a}, pages = {1945 -- 1957}, year = {2012}, abstract = {New hybrid materials have been prepared by grafting synthetic peptides in the interlayer spacing of Cu(II) and Co(II) layered simple hydroxides (LSHs). The interlayer spacing of the hybrids depends on the peptide chain length; the dependence is specific for the copper and cobalt-based hybrids. This suggests a metal-or LSH-specific interaction of the peptides with the respective inorganic layers. When tyrosine is present in the peptide, its fluorescence is quenched after grafting the peptide to the LSH. Studies of the luminescence vs. pH indicate deprotonation of the tyrosine moieties to tyrosinate at high pH, accompanied by the onset of luminescence. The luminescence increases with increasing OH- concentration, suggesting an application of the hybrids as chemical sensors. Moreover, the peptides influence the magnetic properties of the hybrids. The copper-based hybrids behave antiferromagnetically and the cobalt-based hybrids are ferrimagnets.}, language = {en} } @article{DelahayeGoebelLoebbickeetal.2012, author = {Delahaye, Emilie and Goebel, Ronald and Loebbicke, Ruben and Guillot, Regis and Sieber, Christoph and Taubert, Andreas}, title = {Silica ionogels for proton transport}, series = {Journal of materials chemistry}, volume = {22}, journal = {Journal of materials chemistry}, number = {33}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {0959-9428}, doi = {10.1039/c2jm00037g}, pages = {17140 -- 17146}, year = {2012}, abstract = {A number of ionogels - silica-ionic liquid (IL) hybrid materials - were synthesized and studied for their ionic conductivity. The materials are based on a sulfonated IL, 1-methyl-3-(3-sulfopropyl-)-imidazolium p-toluenesulfonate, [PmimSO(3)H][PTS], which contains a sulfonic acid/sulfonate group both in the IL anion and in the side chain of the IL cation. By way of the sulfonate-sulfonic acid proton transfer, the IL imparts the ionogel with a high ionic conductivity of ca. 10(-2) S cm(-1) in the as-synthesized state at 120 degrees C and 10(-3) S cm(-1) in the dry state at 120 degrees C. The ionogels are stable up to ca. 150 degrees C in dynamic thermogravimetric analysis. This suggests that these materials, which are relatively cheap and easily fabricated, could find application in fuel cells in intermediate temperature ranges where many other membrane materials are not suitable.}, language = {en} } @article{GoebelWhiteTitiricietal.2012, author = {Goebel, Ronald and White, Robin J. and Titirici, Maria-Magdalena and Taubert, Andreas}, title = {Carbon-based ionogels tuning the properties of the ionic liquid via carbon-ionic liquid interaction}, series = {Physical chemistry, chemical physics : a journal of European Chemical Societies}, volume = {14}, journal = {Physical chemistry, chemical physics : a journal of European Chemical Societies}, number = {17}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1463-9076}, doi = {10.1039/c2cp23929a}, pages = {5992 -- 5997}, year = {2012}, abstract = {The behavior of two ionic liquids (ILs), 1-ethyl-3-methylimidazolium dicyanamide [Emim][DCA] and 1-ethyl-3-methylimidazolium triflate [Emim][TfO], in (meso) porous carbonaceous hosts was investigated. Prior to IL incorporation into the host, the carbon matrix was thermally annealed between 180 and 900 degrees C to control carbon condensation and surface chemistry. The resulting materials have an increasing "graphitic'' carbon character with increasing treatment temperature, reflected in a modified behavior of the ILs when impregnated into the carbon host. The two ILs show significant changes in the thermal behavior as measured from differential scanning calorimetry; these changes can be assigned to anion-pi interaction between the IL anions and the pore wall surfaces of these flexible carbonaceous support materials.}, language = {en} } @article{NeumannNoeskeTaubertetal.2012, author = {Neumann, Mike and Noeske, Robert and Taubert, Andreas and Tiersch, Brigitte and Strauch, Peter}, title = {Highly structured, biomorphous beta-SiC with high specific surface area from Equisetaceae}, series = {Journal of materials chemistry}, volume = {22}, journal = {Journal of materials chemistry}, number = {18}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {0959-9428}, doi = {10.1039/c2jm30253e}, pages = {9046 -- 9051}, year = {2012}, abstract = {Mesoporous, highly structured silicon carbide (beta-SiC) was synthesised from renewable plant materials (two Equisetaceae species) in a one-step carbothermal process at remarkably low temperatures down to 1200 degrees C. The SiC precursor is a silicon-carbon mixture with finely dispersed carbon prepared by pyrolysis of the organic plant matrix. Yields are 3 to 100\% (omega(Si/Si) related to the silicon deposited in the plant material), depending on reaction temperature and time. IR spectroscopy, X-ray diffraction, and nitrogen sorption prove the formation of high-purity beta-SiC with minor inorganic impurities after purification and a high specific surface area of up to 660 m(2) g(-1). Scanning electron microscopy shows that the plant morphology is maintained in the final SiC. Sedimentation analysis finds a mean particle size (diameters d(50)) of 20 mu m.}, language = {en} } @article{TaubertStangeLietal.2012, author = {Taubert, Andreas and Stange, Franziska and Li, Zhonghao and Junginger, Mathias and G{\"u}nter, Christina and Neumann, Mike and Friedrich, Alwin}, title = {CuO nanoparticles from the Strongly Hydrated Ionic Liquid Precursor (ILP) Tetrabutylammonium Hydroxide evaluation of the Ethanol Sensing Activity}, series = {ACS applied materials \& interfaces}, volume = {4}, journal = {ACS applied materials \& interfaces}, number = {2}, publisher = {American Chemical Society}, address = {Washington}, issn = {1944-8244}, doi = {10.1021/am201427q}, pages = {791 -- 795}, year = {2012}, abstract = {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.}, language = {en} } @article{GoebelXieNeumannetal.2012, author = {Goebel, Ronald and Xie, Zai-Lai and Neumann, Mike and G{\"u}nter, Christina and Loebbicke, Ruben and Kubo, Shiori and Titirici, Maria-Magdalena and Giordano, Cristina and Taubert, Andreas}, title = {Synthesis of mesoporous carbon/iron carbide hybrids with unusually high surface areas from the ionic liquid precursor [Bmim][FeCl4]}, series = {CrystEngComm}, volume = {14}, journal = {CrystEngComm}, number = {15}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1466-8033}, doi = {10.1039/c2ce25064k}, pages = {4946 -- 4951}, year = {2012}, abstract = {Mesoporous carbon/iron carbide hybrid materials with surface areas reaching 800 m(2) g(-1) were synthesized via an exotemplating route using monolithic mesoporous silica as template and the ionic liquid 1-butyl-3-methylimidazolium tetrachloridoferrate(III) [Bmim][FeCl4] as carbon and iron source. After heat treatment (750 degrees C under argon) of the [Bmim][FeCl4] precursor confined within the silica matrix, the silica exotemplate was removed with HF leaving the mesoporous C/Fe3C hybrid behind. The surface areas and the pore sizes depend on the exotemplate and the surface areas a significantly larger than any other surface area reported for C/Fe3C hybrid materials so far. The approach is thus a prototype for the synthesis of high-surface area iron carbide-based hybrid materials with potential application in catalysis.}, language = {en} } @article{WangLackXieetal.2012, author = {Wang, Feipeng and Lack, Alexander and Xie, Zailai and Fr{\"u}bing, Peter and Taubert, Andreas and Gerhard, Reimund}, title = {Ionic-liquid-induced ferroelectric polarization in poly(vinylidene fluoride) thin films}, series = {Applied physics letters}, volume = {100}, journal = {Applied physics letters}, number = {6}, publisher = {American Institute of Physics}, address = {Melville}, issn = {0003-6951}, doi = {10.1063/1.3683526}, pages = {4}, year = {2012}, abstract = {Thin films of ferroelectric beta-phase poly(vinylidene fluoride) (PVDF) were spin-coated from a solution that contained small amounts of the ionic liquid (IL) 1-ethyl-3-methylimidazolium nitrate. A remanent polarization of 60 mC/m(2) and a quasi-static pyroelectric coefficient of 19 mu C/m(2)K at 30 degrees C were observed in the films. It is suggested that the IL promotes the formation of the beta phase through dipolar interactions between PVDF chain-molecules and the IL. The dipolar interactions are identified as Coulomb attraction between hydrogen atoms in PVDF chains and anions in IL. The strong crystallinity increase is probably caused by the same dipolar interaction as well.}, language = {en} } @article{DraudeGallaPelsteretal.2013, author = {Draude, F. and Galla, S. and Pelster, Axel and Tentschert, J. and Jungnickel, H. and Haase, Alfred and Mantion, Alexandre and Thuenemann, Andreas F. and Taubert, Andreas and Luch, A. and Arlinghaus, H. F.}, title = {ToF-SIMS and Laser-SNMS analysis of macrophages after exposure to silver nanoparticles}, series = {Surface and interface analysis : an international journal devoted to the development and application of techniques for the analysis surfaces, interfaces and thin films}, volume = {45}, journal = {Surface and interface analysis : an international journal devoted to the development and application of techniques for the analysis surfaces, interfaces and thin films}, number = {1}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0142-2421}, doi = {10.1002/sia.4902}, pages = {286 -- 289}, year = {2013}, abstract = {Silver nanoparticles (SNPs) are among the most commercialized nanoparticles because of their antibacterial effects. Besides being employed, e. g. as a coatingmaterial for sterile surfaces in household articles and appliances, the particles are also used in a broad range of medical applications. Their antibacterial properties make SNPs especially useful for wound disinfection or as a coating material for prostheses and surgical instruments. Because of their optical characteristics, the particles are of increasing interest in biodetection as well. Despite the widespread use of SNPs, there is little knowledge of their toxicity. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and laser post-ionization secondary neutral mass spectrometry (Laser-SNMS) were used to investigate the effects of SNPs on human macrophages derived from THP-1 cells in vitro. For this purpose, macrophages were exposed to SNPs. The SNP concentration ranges were chosen with regard to functional impairments of the macrophages. To optimize the analysis of the macrophages, a special silicon wafer sandwich preparation technique was employed; ToF-SIMS was employed to characterize fragments originating from macrophage cell membranes. With the use of this optimized sample preparation method, the SNP-exposed macrophages were analyzed with ToF-SIMS and with Laser-SNMS. With Laser-SNMS, the three-dimensional distribution of SNPs in cells could be readily detected with very high efficiency, sensitivity, and submicron lateral resolution. We found an accumulation of SNPs directly beneath the cell membrane in a nanoparticular state as well as agglomerations of SNPs inside the cells.}, language = {en} } @article{JungingerKuebelSchacheretal.2013, author = {Junginger, Mathias and K{\"u}bel, Christian and Schacher, Felix H. and M{\"u}ller, Axel H. E. and Taubert, Andreas}, title = {Crystal structure and chemical composition of biomimetric calcium phosphate nanofibers}, doi = {10.1039/c3ra23348k}, year = {2013}, abstract = {Calcium phosphate nanofibers with a diameter of only a few nanometers and a cotton-ball-like aggregate morphology have been reported several times in the literature. Although fiber formation seems reproducible in a variety of conditions, the crystal structure and chemical composition of the fibers have been elusive. Using scanning transmission electron microscopy, low dose electron (nano)diffraction, energy-dispersive X-ray spectroscopy, and energy- filtered transmission electron microscopy, we have assigned crystal structures and chemical compositions to the fibers. Moreover, we demonstrate that the mineralization process yields true polymer/calcium phosphate hybrid materials where the block copolymer template is closely associated with the calcium phosphate.}, language = {en} } @misc{BleekTaubert2013, author = {Bleek, Katrin and Taubert, Andreas}, title = {New developments in polymer-controlled, bioinspired calcium phosphate mineralization from aqueous solution}, series = {Acta biomaterialia}, volume = {9}, journal = {Acta biomaterialia}, number = {5}, publisher = {Elsevier}, address = {Oxford}, issn = {1742-7061}, doi = {10.1016/j.actbio.2012.12.027}, pages = {6283 -- 6321}, year = {2013}, abstract = {The polymer-controlled and bioinspired precipitation of inorganic minerals from aqueous solution at near-ambient or physiological conditions avoiding high temperatures or organic solvents is a key research area in materials science. Polymer-controlled mineralization has been studied as a model for biomineralization and for the synthesis of (bioinspired and biocompatible) hybrid materials for a virtually unlimited number of applications. Calcium phosphate mineralization is of particular interest for bone and dental repair. Numerous studies have therefore addressed the mineralization of calcium phosphate using a wide variety of low- and high-molecular-weight additives. In spite of the growing interest and increasing number of experimental and theoretical data, the mechanisms of polymer-controlled calcium phosphate mineralization are not entirely clear to date, although the field has made significant progress in the last years. A set of elegant experiments and calculations has shed light on some details of mineral formation, but it is currently not possible to preprogram a mineralization reaction to yield a desired product for a specific application. The current article therefore summarizes and discusses the influence of (macro)molecular entities such as polymers, peptides, proteins and gels on biomimetic calcium phosphate mineralization from aqueous solution. It focuses on strategies to tune the kinetics, morphologies, final dimensions and crystal phases of calcium phosphate, as well as on mechanistic considerations.}, language = {en} } @article{BagdahnTaubert2013, author = {Bagdahn, Christian and Taubert, Andreas}, title = {Ionogel fiber mats - functional materials via electrospinning of PMMA and the ionic liquid bis(1-butyl-3-methyl-imidazolium) Tetrachloridocuprate(II), [Bmim](2)[CuCl4]}, series = {Zeitschrift f{\"u}r Naturforschung : B, Chemical sciences}, volume = {68}, journal = {Zeitschrift f{\"u}r Naturforschung : B, Chemical sciences}, number = {10}, publisher = {De Gruyter}, address = {T{\"u}bingen}, issn = {0932-0776}, doi = {10.5560/ZNB.2013-3195}, pages = {1163 -- 1171}, year = {2013}, abstract = {Ionogel fiber mats were made by electrospinning poly(methylmethacrylate) (PMMA) and the ionic liquid (IL) bis(1-butyl-3-methyl-imidazolium) tetrachloridocupraten, [Bmim](2)[CuCl4], from acetone. The morphology of the electrospun ionogels strongly depends on the spinning parameters. Dense and uniform fiber mats were only obtained at concentrations of 60 to 70 g of polymer and IL mass combined. Lower concentrations led to a low number of poorly defined fibers. High voltages of 20 to 25 kV led to well-defined and uniform fibers; voltages between 15 and 20 kV again led to less uniform and less dense fibers. At 10 kV and lower, no spinning could be induced. Finally, PMMA fibers electrospun without IL show a less well-defined morphology combining fibers and oblong droplets indicating that the IL has a beneficial effect on the electrospinning process. The resulting materials are prototypes for new functional materials, for example in sterile filtration.}, language = {en} } @misc{BleekTaubert2013, author = {Bleek, Katrin and Taubert, Andreas}, title = {New developments in polymer-controlled, bio-inspired calcium phosphate mineralization from aqueous solution}, series = {Acta biomaterialia}, volume = {9}, journal = {Acta biomaterialia}, number = {9}, publisher = {Elsevier}, address = {Oxford}, issn = {1742-7061}, doi = {10.1016/j.actbio.2013.05.007}, pages = {8466 -- 8466}, year = {2013}, language = {en} } @article{TentschertDraudeJungnickeletal.2013, author = {Tentschert, J. and Draude, F. and Jungnickel, H. and Haase, A. and Mantion, Alexandre and Galla, S. and Thuenemann, Andreas F. and Taubert, Andreas and Luch, A. and Arlinghaus, H. F.}, title = {TOF-SIMS analysis of cell membrane changes in functional impaired human macrophages upon nanosilver treatment}, series = {Surface and interface analysis : an international journal devoted to the development and application of techniques for the analysis surfaces, interfaces and thin films}, volume = {45}, journal = {Surface and interface analysis : an international journal devoted to the development and application of techniques for the analysis surfaces, interfaces and thin films}, number = {1}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0142-2421}, doi = {10.1002/sia.5155}, pages = {483 -- 485}, year = {2013}, abstract = {Silver nanoparticles (SNP) are among the most commercialized nanoparticles. Here, we show that peptide-coated SNP cause functional impairment of human macrophages. A dose-dependent inhibition of phagocytosis is observed after nanoparticle treatment, and pretreatment of cells with N-acetyl cysteine (NAC) can counteract the phagocytosis disturbances caused by SNP. Using the surface-sensitive mode of time-of-flight secondary ion mass spectrometry, in combination with multivariate statistical methods, we studied the composition of cell membranes in human macrophages upon exposure to SNP with and without NAC preconditioning. This method revealed characteristic changes in the lipid pattern of the cellular membrane outer leaflet in those cells challenged by SNP. Statistical analyses resulted in 19 characteristic ions, which can be used to distinguish between NAC pretreated and untreated macrophages. The present study discusses the assignments of surface cell membrane phospholipids for the identified ions and the resulting changes in the phospholipid pattern of treated cells. We conclude that the adverse effects in human macrophages caused by SNP can be partially reversed through NAC administration. Some alterations, however, remained.}, language = {en} } @article{JungingerKuebelSchacheretal.2013, author = {Junginger, Mathias and K{\"u}bel, Christian and Schacher, Felix H. and M{\"u}ller, Axel H. E. and Taubert, Andreas}, title = {Crystal structure and chemical composition of biomimetic calcium phosphate nanofibers}, series = {RSC Advances}, volume = {3}, journal = {RSC Advances}, number = {28}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {2046-2069}, doi = {10.1039/c3ra23348k}, pages = {11301 -- 11308}, year = {2013}, abstract = {Calcium phosphate nanofibers with a diameter of only a few nanometers and a cotton-ball-like aggregate morphology have been reported several times in the literature. Although fiber formation seems reproducible in a variety of conditions, the crystal structure and chemical composition of the fibers have been elusive. Using scanning transmission electron microscopy, low dose electron (nano) diffraction, energy-dispersive X-ray spectroscopy, and energy-filtered transmission electron microscopy, we have assigned crystal structures and chemical compositions to the fibers. Moreover, we demonstrate that the mineralization process yields true polymer/calcium phosphate hybrid materials where the block copolymer template is closely associated with the calcium phosphate.}, language = {en} } @misc{WinterThielZabeletal.2013, author = {Winter, Alette and Thiel, Kerstin and Zabel, Andr{\´e} and Klamroth, Tillmann and P{\"o}ppl, Andreas and Kelling, Alexandra and Schilde, Uwe and Taubert, Andreas and Strauch, Peter}, title = {Tetrahalidocuprates(II) - structure and EPR spectroscopy}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-95012}, pages = {1019 -- 1030}, year = {2013}, abstract = {We present and discuss the results of crystallographic and electron paramagnetic resonance (EPR) spectroscopic analyses of five tetrachloridocuprate(II) complexes to supply a useful tool for the structural characterisation of the [CuCl4]2- moiety in the liquid state, for example in ionic liquids, or in solution. Bis(benzyltriethylammonium)-, bis(trimethylphenylammonium)-, bis(ethyltriphenylphosphonium)-, bis(benzyltriphenylphosphonium)-, and bis(tetraphenylarsonium)tetrachloridocuprate(II) were synthesised and characterised by elemental, IR, EPR and X-ray analyses. The results of the crystallographic analyses show distorted tetrahedral coordination geometry of all [CuCl4]2- anions in the five complexes and prove that all investigated complexes are stabilised by hydrogen bonds of different intensities. Despite the use of sterically demanding ammonium, phosphonium and arsonium cations to obtain the separation of the paramagnetic Cu(II) centres for EPR spectroscopy no hyperfine structure was observed in the EPR spectra but the principal values of the electron Zeeman tensor, g∥ and g⊥, could be determined. With these EPR data and the crystallographic parameters we were able to carry out a correlation study to anticipate the structural situation of tetrachloridocuprates in different physical states. This correlation is in good agreement with DFT calculations.}, language = {en} } @misc{JungingerKuebelSchacheretal.2013, author = {Junginger, Mathias and K{\"u}bel, Christian and Schacher, Felix H. and M{\"u}ller, Axel H. E. and Taubert, Andreas}, title = {Crystal structure and chemical composition of biomimetic calcium phosphate nanofibers}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-95176}, pages = {11301 -- 11308}, year = {2013}, abstract = {Calcium phosphate nanofibers with a diameter of only a few nanometers and a cotton-ball-like aggregate morphology have been reported several times in the literature. Although fiber formation seems reproducible in a variety of conditions, the crystal structure and chemical composition of the fibers have been elusive. Using scanning transmission electron microscopy, low dose electron (nano)diffraction, energy-dispersive X-ray spectroscopy, and energy-filtered transmission electron microscopy, we have assigned crystal structures and chemical compositions to the fibers. Moreover, we demonstrate that the mineralization process yields true polymer/calcium phosphate hybrid materials where the block copolymer template is closely associated with the calcium phosphate.}, language = {en} } @article{UnuabonahGuenterWeberetal.2013, author = {Unuabonah, Emmanuel Iyayi and G{\"u}nter, Christina and Weber, Jens and Lubahn, Susanne and Taubert, Andreas}, title = {Hybrid Clay - a new highly efficient adsorbent for water treatment}, series = {ACS sustainable chemistry \& engineering}, volume = {1}, journal = {ACS sustainable chemistry \& engineering}, number = {8}, publisher = {American Chemical Society}, address = {Washington}, issn = {2168-0485}, doi = {10.1021/sc400051y}, pages = {966 -- 973}, year = {2013}, abstract = {New hybrid clay adsorbent based on kaolinite clay and Carica papaya seeds with improved cation exchange capacity (CEC), rate of heavy metal ion uptake, and adsorption capacity for heavy metal ions were prepared. The CEC of the new material is ca. 75 meq/100 g in spite of the unexpectedly low surface area (approximate to 19 m(2)/g). Accordingly, the average particle size of the hybrid clay adsorbent decreased from over 200 to 100 pm. The hybrid clay adsorbent is a highly efficient adsorbent for heavy metals. With an initial metal concentration of 1 mg/L, the hybrid clay adsorbent reduces the Cd2+, Ni2+, and Pb2+ concentration in aqueous solution to <= 4, <= 7 and <= 20 mu g/L, respectively, from the first minute to over 300 min using a fixed bed containing 2 g of adsorbent and a flow rate of approximate to 7 mL/min. These values are (with the exception of Pb2+) in line with the WHO permissible limits for heavy metal ions. In a cocktail solution of Cd2+, and Ni2+, the hybrid clay shows a reduced rate of uptake but an increased adsorption capacity. The CEC data suggest that the adsorption of Pb2+, Cd2+, and Ni2+ on the hybrid clay adsorbent is essentially due to ion exchange. This hybrid clay adsorbent is prepared from materials that are abundant and by a simple means that is sustainable, easily recovered from aqueous solution, nonbiodegradable (unlike numerous biosorbent), and easily regenerated and is a highly efficient alternative to activated carbon for water treatment.}, language = {en} }