@article{ZuehlkeZenichowskiRiebeetal.2017, author = {Z{\"u}hlke, Martin and Zenichowski, Karl and Riebe, Daniel and Beitz, Toralf and L{\"o}hmannsr{\"o}ben, Hans-Gerd}, title = {Subambient pressure electrospray ionization ion mobility spectrometry}, series = {International journal for ion mobility spectrometry : official publication of the International Society for Ion Mobility Spectrometry}, volume = {20}, journal = {International journal for ion mobility spectrometry : official publication of the International Society for Ion Mobility Spectrometry}, publisher = {Springer}, address = {Heidelberg}, issn = {1435-6163}, doi = {10.1007/s12127-017-0215-x}, pages = {47 -- 56}, year = {2017}, abstract = {The pressure dependence of sheath gas assisted electrospray ionization (ESI) was investigated based on two complementary experimental setups, namely an ESI-ion mobility (IM) spectrometer and an ESI capillary - Faraday plate setup housed in an optically accessible vacuum chamber. The ESI-IM spectrometer is capable of working in the pressure range between 300 and 1000 mbar. Another aim was the assessment of the analytical capabilities of a subambient pressure ESI-IM spectrometer. The pressure dependence of ESI was characterized by imaging the electrospray and recording current-voltage (I-U) curves. Qualitatively different behavior was observed in both setups. While the current rises continuously with the voltage in the capillary-plate setup, a sharp increase of the current was measured in the IM spectrometer above a pressure-dependent threshold voltage. The different character can be attributed to the detection of different species in both experiments. In the capillary-plate experiment, a multitude of charged species are detected while only desolvated ions attribute to the IM spectrometer signal. This finding demonstrates the utility of IM spectrometry for the characterization of ESI, since in contrast to the capillary-plate setup, the release of ions from the electrospray droplets can be observed. The I-U curves change significantly with pressure. An important result is the reduction of the maximum current with decreasing pressure. The connected loss of ionization efficiency can be compensated by a more efficient transfer of ions in the IM spectrometer at increased E/N. Thus, similar limits of detection could be obtained at 500 mbar and 1 bar.}, language = {en} } @article{ZuehlkeSassRiebeetal.2017, author = {Z{\"u}hlke, Martin and Sass, Stephan and Riebe, Daniel and Beitz, Toralf and L{\"o}hmannsr{\"o}ben, Hans-Gerd}, title = {Real-Time Reaction Monitoring of an Organic Multistep Reaction by Electrospray Ionization-Ion Mobility Spectrometry}, series = {ChemPlusChem}, volume = {82}, journal = {ChemPlusChem}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {2192-6506}, doi = {10.1002/cplu.201700296}, pages = {1266 -- 1273}, year = {2017}, abstract = {The capability of electrospray ionization (ESI)-ion mobility (IM) spectrometry for reaction monitoring is assessed both as a stand-alone real-time technique and in combination with HPLC. A three-step chemical reaction, consisting of a Williamson ether synthesis followed by a hydrogenation and an N-alkylation step, is chosen for demonstration. Intermediates and products are determined with a drift time to mass-per-charge correlation. Addition of an HPLC column to the setup increases the separation power and allows the determination of further species. Monitoring of the intensities of the various species over the reaction time allows the detection of the end of reaction, determination of the rate-limiting step, observation of the system response in discontinuous processes, and optimization of the mass ratios of the starting materials. However, charge competition in ESI influences the quantitative detection of substances in the reaction mixture. Therefore, two different methods are investigated, which allow the quantification and investigation of reaction kinetics. The first method is based on the pre-separation of the compounds on an HPLC column and their subsequent individual detection in the ESI-IM spectrometer. The second method involves an extended calibration procedure, which considers charge competition effects and facilitates nearly real-time quantification.}, language = {en} } @article{ZhongMetwalliRawolleetal.2017, author = {Zhong, Qi and Metwalli, Ezzeldin and Rawolle, Monika and Kaune, Gunar and Bivigou Koumba, Achille Mayelle and Laschewsky, Andre and Papadakis, Christine M. and Cubitt, Robert and Wang, Jiping and M{\"u}ller-Buschbaum, Peter}, title = {Vacuum induced dehydration of swollen poly(methoxy diethylene glycol acrylate) and polystyrene-block-poly(methoxy diethylene glycol acrylate)-block-polystyrene films probed by in-situ neutron reflectivity}, series = {Polymer : the international journal for the science and technology of polymers}, volume = {124}, journal = {Polymer : the international journal for the science and technology of polymers}, publisher = {Elsevier}, address = {Oxford}, issn = {0032-3861}, doi = {10.1016/j.polymer.2017.07.066}, pages = {263 -- 273}, year = {2017}, abstract = {The isothermal vacuum-induced dehydration of thin films made of poly(methoxy diethylene glycol acrylate) (PMDEGA), which were swollen under ambient conditions, is studied. The dehydration behavior of the homopolymer film as well as of a nanostructured film of the amphiphilic triblock copolymer polystyrene-block-poly(methoxy diethylene glycol acrylate)-block-polystyrene, abbreviated as PS-b-PMDEGA-b-PS, are probed, and compared to the thermally induced dehydration behavior of such thin thermo-responsive films when they pass through their LCST-type coil-to globule collapse transition. The dehydration kinetics is followed by in-situ neutron reflectivity measurements. Contrast results from the use of deuterated water. Water content and film thickness are significantly reduced during the process, which can be explained by Schott second order kinetics theory for both films. The water content of the dehydrated equilibrium state from this model is very close to the residual water content obtained from the final static measurements, indicating that residual water still remains in the film even after prolonged exposure to the vacuum. In the PS-b-PMDEGA-b-PS film that shows micro-phase separation, the hydrophobic PS domains modify the dehydration process by hindering the water removal, and thus retarding dehydration by about 30\%. Whereas residual water remains tightly bound in the PMDEGA domains, water is completely removed from the PS domains of the block copolymer film. (C) 2017 Elsevier Ltd. All rights reserved.}, language = {en} } @article{ZhangWillaSunetal.2017, author = {Zhang, Weiyi and Willa, Christoph and Sun, Jian-Ke and Guterman, Ryan and Taubert, Andreas and Yuan, Jiayin}, title = {Polytriazolium poly(ionic liquid) bearing triiodide anions: Synthesis, basic properties and electrochemical behaviors}, series = {Polymer : the international journal for the science and technology of polymers}, volume = {124}, journal = {Polymer : the international journal for the science and technology of polymers}, publisher = {Elsevier}, address = {Oxford}, issn = {0032-3861}, doi = {10.1016/j.polymer.2017.07.059}, pages = {246 -- 251}, year = {2017}, abstract = {4-Methyl-1-vinyl-1,2,4-triazolium triiodide ionic liquid and its polymer poly(4-methyl-1-vinyl-1,2,4-triazolium) triiodide were prepared for the first time from their iodide precursors via the reaction of iodide (I-) with elemental iodine (I-2). The change from iodide to triiodide (I-3(-)) was found to introduce particular variations in the physical properties of these two compounds, including lower melting point/glass transition temperature and altered solubility. The compounds were characterized by single-crystal X-ray diffraction, elemental analysis, and their electrochemical properties examined in solution and in the solid-state. Compared with their iodide analogues, the triiodide salts exhibited lower electrical impedance and higher current in the cyclic voltammetry. We found that poly(4-methyl-1,2,4-triazolium triiodide) was proven to be a promising solid polymer electrolyte candidate. (C) 2017 Elsevier Ltd. All rights reserved.}, language = {en} } @phdthesis{Zhang2017, author = {Zhang, Weiyi}, title = {Functional Poly(ionic liquid) Materials based on Poly(1,2,4-triazolium)s}, school = {Universit{\"a}t Potsdam}, pages = {108}, year = {2017}, language = {en} } @article{ZhangBisterfeldBramskietal.2017, author = {Zhang, Shuhao and Bisterfeld, Carolin and Bramski, Julia and Vanparijs, Nane and De Geest, Bruno G. and Pietruszka, J{\"o}rg and B{\"o}ker, Alexander and Reinicke, Stefan}, title = {Biocatalytically Active Thin Films via Self-Assembly of 2-Deoxy-D-ribose-5-phosphate Aldolase-Poly(N-isopropylacrylamide) Conjugates}, series = {Bioconjugate chemistry}, volume = {29}, journal = {Bioconjugate chemistry}, number = {1}, publisher = {American Chemical Society}, address = {Washington}, issn = {1043-1802}, doi = {10.1021/acs.bioconjchem.7b00645}, pages = {104 -- 116}, year = {2017}, abstract = {2-Deoxy-D-ribose-5-phosphate aldolase (DERA) is a biocatalyst that is capable of converting acetaldehyde and a second aldehyde as acceptor into enantiomerically pure mono- and diyhydroxyaldehydes, which are important structural motifs in a number of pharmaceutically active compounds. However, substrate as well as product inhibition requires a more-sophisticated process design for the synthesis of these motifs. One way to do so is to the couple aldehyde conversion with transport processes, which, in turn, would require an immobilization of the enzyme within a thin film that can be deposited on a membrane support. Consequently, we developed a fabrication process for such films that is based on the formation of DERA-poly(N-isopropylacrylamide) conjugates that are subsequently allowed to self-assemble at an air-water interface to yield the respective film. In this contribution, we discuss the conjugation conditions, investigate the interfacial properties of the conjugates, and, finally, demonstrate a successful film formation under the preservation of enzymatic activity.}, language = {en} } @misc{ZehbeKolloscheLardongetal.2017, author = {Zehbe, Kerstin and Kollosche, Matthias and Lardong, Sebastian and Kelling, Alexandra and Schilde, Uwe and Taubert, Andreas}, title = {Ionogels based on poly(methyl methacrylate) and metal-containing ionic liquids}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-400607}, pages = {16}, year = {2017}, abstract = {Ionogels (IGs) based on poly(methyl methacrylate) (PMMA) and the metal-containing ionic liquids (ILs) bis-1-butyl-3-methlimidazolium tetrachloridocuprate(II), tetrachloride cobaltate(II), and tetrachlorido manganate(II) have been synthesized and their mechanical and electrical properties have been correlated with their microstructure. Unlike many previous examples, the current IGs show a decreasing stability in stress-strain experiments on increasing IL fractions. The conductivities of the current IGs are lower than those observed in similar examples in the literature. Both effects are caused by a two-phase structure with micrometer-sized IL-rich domains homogeneously dispersed an IL-deficient continuous PMMA phase. This study demonstrates that the IL-polymer miscibility and the morphology of the IGs are key parameters to control the (macroscopic) properties of IGs.}, language = {en} } @article{YouBehlLoewenbergetal.2017, author = {You, Zewang and Behl, Marc and L{\"o}wenberg, Candy and Lendlein, Andreas}, title = {pH-sensitivity and conformation change of the n-terminal methacrylated peptide VK20}, series = {MRS advances : a journal of the Materials Research Society (MRS)}, volume = {2}, journal = {MRS advances : a journal of the Materials Research Society (MRS)}, publisher = {Cambridge University Press}, address = {Cambridge}, issn = {2059-8521}, doi = {10.1557/adv.2017.491}, pages = {2571 -- 2579}, year = {2017}, abstract = {N-terminal methacrylation of peptide MAXI, which is capable of conformational changes variation of the pH, results in a peptide, named VK20. Increasing the reactivity of this terminal group enables further coupling reactions or chemical modifications of the peptidc. However, this end group functionalization may influence the ability of confonnational changes of VK20; as well as its properties. In this paper; the influence of pH on the transition between random coil and beta-sheet conformation of VK20; including the transition kinetics, were investigated. At pH values of 9 and higher, the kinetics beta-sheet formation increased tor VK(2 0, compared to MAXI. The self-assembly into beta-sheets recognized by the formation of a physically crosslinked gel was furthermore indicated by a significant increase of G. An increase in pH (from 9 to 9.5) led to a faster gelation of the peptide VK20. Simultaneously, G was increased from 460 +/- 70 Pa (at pH 9) to 1520 +/- 180 Pa (at pH 9.5). At the nanoscale, the gel showed a highly interconnected fibrillar/network structure with uniform fibril widths of approximately 3.4 +/- 0.5 nm (N=30). The recovery of the peptide conformation back to random coil resulted in the dissolution of the gel; whereby the kinetics of the recovery depended on the pH. Conclusively, the ability of MAXI to undergo confommtional changes was not affected by N-terminal methacrylation whereas the kinetics of pH-sensitive beta-sheet formations has been increased.}, language = {en} } @phdthesis{You2017, author = {You, Zewang}, title = {Conformational transition of peptide-functionalized cryogels enabling shape-memory capability}, school = {Universit{\"a}t Potsdam}, pages = {144}, year = {2017}, language = {en} } @article{YangDingKochovskietal.2017, author = {Yang, Guang and Ding, Hong-ming and Kochovski, Zdravko and Hu, Rongting and Lu, Yan and Ma, Yu-qiang and Chen, Guosong and Jiang, Ming}, title = {Highly Ordered Self-Assembly of Native Proteins into 1D, 2D, and 3D Structures Modulated by the Tether Length of Assembly-Inducing Ligands}, series = {Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition}, volume = {56}, journal = {Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1433-7851}, doi = {10.1002/anie.201703052}, pages = {10691 -- 10695}, year = {2017}, abstract = {In nature, proteins self-assemble into various structures with different dimensions. To construct these nanostructures in laboratories, normally proteins with different symmetries are selected. However, most of these approaches are engineering-intensive and highly dependent on the accuracy of the protein design. Herein, we report that a simple native protein LecA assembles into one-dimensional nanoribbons and nanowires, two-dimensional nanosheets, and three-dimensional layered structures controlled mainly by small-molecule assembly-inducing ligands RnG (n = 1, 2, 3, 4, 5) with varying numbers of ethylene oxide repeating units. To understand the formation mechanism of the different morphologies controlled by the small-molecule structure, molecular simulations were performed from microscopic and mesoscopic view, which presented a clear relationship between the molecular structure of the ligands and the assembled patterns. These results introduce an easy strategy to control the assembly structure and dimension, which could shed light on controlled protein assembly.}, language = {en} }