@article{DiezTauerSchulz2006, author = {Diez, Isabel and Tauer, Klaus and Schulz, Burkhard}, title = {Unusual polymer dispersions-polypyrrole suspensions made of rings, frames, and platelets}, series = {Colloid and polymer science : official journal of the Kolloid-Gesellschaft}, volume = {284}, journal = {Colloid and polymer science : official journal of the Kolloid-Gesellschaft}, publisher = {Springer}, address = {New York}, issn = {0303-402X}, doi = {10.1007/s00396-006-1521-8}, pages = {1431 -- 1442}, year = {2006}, abstract = {Experimental results show that the polymerization of pyrrole in the presence of beta-naphthalenesulfonic acid and different fluorosurfactants like perfluorooctanesulfonic acid, perfluorooctyldiethanolamide, and ammonium perfluorooctanoate leads to polypyrrole with special morphologies, such as rings or disks and rectangular frames or plates. The formation of these unusually shaped particles of polymer dispersions is explained by the chemical and colloidal peculiarities of the oxidative pyrrole polymerization with ammonium peroxodisulfate in aqueous medium.}, language = {en} } @article{SchulzOrgzallDiezetal.2010, author = {Schulz, Burkhard and Orgzall, Ingo and Diez, Isabel and Dietzel, Birgit and Tauer, Klaus}, title = {Template mediated formation of shaped polypyrrole particles}, issn = {0927-7757}, doi = {10.1016/j.colsurfa.2009.11.034}, year = {2010}, abstract = {The formation of different micro- and nanostructures during the chemical synthesis of polypyrrole is reviewed shortly based on the conceptions of hard- and soft-templating models. Contrary to other models that emphasize the role of micelles it is found here that during the oxidative polymerization of pyrole using sulfonic acid dopants a crystalline hard template is found in the first steps of the reaction before the addition of the oxidant. This template is formed by a complex consisting of 2,5-bis(pyrrole-2-yl)pyrrolidine and the sulfonic acid anion. The acid catalyzed formation of this specific tripyrrole is discussed. (C) 2009 Elsevier B.V. All rights reserved.}, language = {en} } @article{VacogneWeiTaueretal.2018, author = {Vacogne, Charlotte Dominique and Wei, Chunxiang and Tauer, Klaus and Schlaad, Helmut}, title = {Self-assembly of alpha-helical polypeptides into microscopic and enantiomorphic spirals}, series = {Journal of the american chemical society}, volume = {140}, journal = {Journal of the american chemical society}, number = {36}, publisher = {American Chemical Society}, address = {Washington}, issn = {0002-7863}, doi = {10.1021/jacs.8b06503}, pages = {11387 -- 11394}, year = {2018}, abstract = {Helical structures are ubiquitous in biological materials and often serve a structural purpose. Bioinspired helical materials can be challenging to synthesize and rarely reach the degree of hierarchy of their natural counterparts. Here we report the first example of particles synthesized by direct emulsification of polypeptides found to display spiral morphologies in the dry state. The polypeptides were alpha-helical homo- and copolypeptides of gamma-benzyl glutamate and allylglycine. The chirality of the spirals was controlled by the chirality of the alpha-helices. Notably, right-handed alpha-helical polypeptides (rich in 1, residues) produced clockwise spirals, whereas left-handed alpha-helical polypeptides (rich in D residues) produced the enantiomorphs, i.e., counterclockwise spirals. The disruption of the alpha-helical conformation by the introduction of chiral defects led to less regular spirals and in some cases their suppression. A hypothesis for the transmission of helicity and chirality from a molecular to a higher hierarchical level, involving fibril bundling of coiled alpha-helices, is proposed.}, language = {en} } @article{DiezTauerSchulz2004, author = {Diez, Isabel and Tauer, Klaus and Schulz, Burkhard}, title = {Polypyrrole tubes via casting of pyrrole-beta-naphthalenesulfonic acid rods}, issn = {0303-402X}, year = {2004}, abstract = {A comprehensive study gives experimental evidence that a complex made from pyrrole and beta-naphthalenesulfonic acid in a molar composition of 3:1 acts as morphological precursor in the subsequent oxidative polymerization of pyrrole initiated with ammonium peroxodisulfate. The precursor complex itself is unable to polymerize but its outer parallelepipedal shape with a high aspect ratio is templated in the inner surface of the formed conducting polypyrrole tubes}, language = {en} } @article{HentrichTauerEspanoletal.2017, author = {Hentrich, Doreen and Tauer, Klaus and Espanol, Montserrat and Ginebra, Maria-Pau and Taubert, Andreas}, title = {EDTA and NTA effectively tune the mineralization of calcium phosphate from bulk aqueous solution}, series = {Biomimetics}, volume = {2}, journal = {Biomimetics}, number = {4}, publisher = {MDPI}, address = {Basel}, issn = {2313-7673}, doi = {10.3390/biomimetics2040024}, pages = {21}, year = {2017}, abstract = {This study describes the effects of nitrilotriacetic acid (NTA) and ethylenediaminotetraacetic acid (EDTA) on themineralization of calciumphosphate from bulk aqueous solution. Mineralization was performed between pH 6 and 9 and with NTA or EDTA concentrations of 0, 5, 10, and 15 mM. X-ray diffraction and infrared spectroscopy show that at low pH, mainly brushite precipitates and at higher pH, mostly hydroxyapatite forms. Both additives alter the morphology of the precipitates. Without additive, brushite precipitates as large plates. With NTA, the morphology changes to an unusual rod-like shape. With EDTA, the edges of the particles are rounded and disk-like particles form. Conductivity and pH measurements suggest that the final products form through several intermediate steps.}, language = {en} } @misc{HentrichTauerEspanoletal.2017, author = {Hentrich, Doreen and Tauer, Klaus and Espanol, Montserrat and Ginebra, Maria-Pau and Taubert, Andreas}, title = {EDTA and NTA effectively tune the mineralization of calcium phosphate from bulk aqueous solution}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1095}, issn = {1866-8372}, doi = {10.25932/publishup-46918}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-469186}, pages = {23}, year = {2017}, abstract = {This study describes the effects of nitrilotriacetic acid (NTA) and ethylenediaminotetraacetic acid (EDTA) on themineralization of calciumphosphate from bulk aqueous solution. Mineralization was performed between pH 6 and 9 and with NTA or EDTA concentrations of 0, 5, 10, and 15 mM. X-ray diffraction and infrared spectroscopy show that at low pH, mainly brushite precipitates and at higher pH, mostly hydroxyapatite forms. Both additives alter the morphology of the precipitates. Without additive, brushite precipitates as large plates. With NTA, the morphology changes to an unusual rod-like shape. With EDTA, the edges of the particles are rounded and disk-like particles form. Conductivity and pH measurements suggest that the final products form through several intermediate steps.}, language = {en} } @article{PehLiedelTaubertetal.2017, author = {Peh, Eddie and Liedel, Clemens and Taubert, Andreas and Tauer, Klaus}, title = {Composition inversion to form calcium carbonate mixtures}, series = {CrystEngComm}, volume = {19}, journal = {CrystEngComm}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1466-8033}, doi = {10.1039/c7ce00433h}, pages = {3573 -- 3583}, year = {2017}, abstract = {Composition inversion takes place in equimolar solid mixtures of sodium or ammonium carbonate and calcium chloride with respect to the combination of anions and cations leading to the corresponding chloride and calcite in complete conversion. The transformation takes place spontaneously under a variety of different situations, even in a powdery mixture resting under ambient conditions. Powder X-ray diffraction data and scanning electron microscopy micrographs are presented to describe the course of the reaction and to characterize the reaction products. The incomplete reaction in the interspace between two compressed tablets of pure starting materials leads to an electric potential due to the presence of uncompensated charges.}, language = {en} } @article{WeberTierschUnterlassetal.2011, author = {Weber, Nancy and Tiersch, Brigitte and Unterlass, Miriam M. and Heilig, Anneliese and Tauer, Klaus}, title = {"Schizomorphic" Emulsion Copolymerization Particles}, series = {Macromolecular rapid communications}, volume = {32}, journal = {Macromolecular rapid communications}, number = {23}, publisher = {Wiley-Blackwell}, address = {Malden}, issn = {1022-1336}, doi = {10.1002/marc.201100491}, pages = {1925 -- 1929}, year = {2011}, abstract = {Cryo-electron microscopy, atomic force microscopy, and light microscopy investigations provide experimental evidence that amphiphilic emulsion copolymerization particles change their morphology in dependence on concentration. The shape of the particles is spherical at solids content above 1\%, but it changes to rod-like, ring-like, and web-like structures at lower concentrations. In addition, the shape and morphology of these particles at low concentrations are not fixed but very flexible and vary with time between spheres, flexible pearlnecklace structures, and stretched rods.}, language = {en} }