Search

Your search keyword '"Lieberwirth I"' showing total 6 results
Start Over Author "Lieberwirth I" Publisher wiley-vch verlag
6 results on '"Lieberwirth I"'

1. Extraordinary Performance of Carbon-Coated Anatase TiO2 as Sodium-Ion Anode

Author

Tahir, M.N., Oschmann, B., Buchholz, D., Dou, X., Lieberwirth, I., Panthöfer, M., Tremel, W., Zentel, R., and Passerini, S.

Subjects
anatase TiO2, Technology, RAFT polymerization, carbon coating, sodium-ion batteries, nanoparticles, ddc:600
Abstract

The synthesis of in situ polymer-functionalized anatase TiO2 particles using an anchoring block copolymer with hydroxamate as coordinating species is reported, which yields nanoparticles (≈11 nm) in multigram scale. Thermal annealing converts the polymer brushes into a uniform and homogeneous carbon coating as proven by high resolution transmission electron microscopy and Raman spectroscopy. The strong impact of particle size as well as carbon coating on the electrochemical performance of anatase TiO2 is demonstrated. Downsizing the particles leads to higher reversible uptake/release of sodium cations per formula unit TiO2 (e.g., 0.72 eq. Na+ (11 nm) vs only 0.56 eq. Na+ (40 nm)) while the carbon coating improves rate performance. The combination of small particle size and homogeneous carbon coating allows for the excellent electrochemical performance of anatase TiO2 at high (134 mAh g−1 at 10 C (3.35 A g−1)) and low (≈227 mAh g−1 at 0.1 C) current rates, high cycling stability (full capacity retention between 2nd and 300th cycle at 1 C) and improved coulombic efficiency (≈99.8%).

Published
2016

2. Hierarchical self-assembly of PDMA-b-PS chains into granular nanoparticles: Genesis and fate

Author

Bianchi, A, Mauri, M, Bonetti, S, Koynov, K, Kappl, M, Lieberwirth, I, Butt, H, Simonutti, R, BIANCHI, ALBERTO, MAURI, MICHELE, BONETTI, SIMONE, SIMONUTTI, ROBERTO, Bianchi, A, Mauri, M, Bonetti, S, Koynov, K, Kappl, M, Lieberwirth, I, Butt, H, Simonutti, R, BIANCHI, ALBERTO, MAURI, MICHELE, BONETTI, SIMONE, and SIMONUTTI, ROBERTO

Abstract

The hierarchical self-assembly of an amphiphilic block copolymer, poly( N,N-dimethylacrylamide)-block-polystyrene with a very short hydrophilic block (PDMA10-b-PS62), in large granular nanoparticles is reported. While these nanoparticles are stable in water, their disaggregation can be induced either mechanically (i.e., by applying a force via the tip of the cantilever of an atomic force microscope (AFM)) or by partial hydrolysis of the acrylamide groups. AFM force spectroscopy images show the rupture of the particle as a combination of collapse and flow, while scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images of partly hydrolyzed nanoparticles provide a clear picture of the granular structure. (Chemical Equation Presented).

Published
2014

3. Hierarchical self-assembly of PDMA-b-PS chains into granular nanoparticles: Genesis and fate

Author

Roberto Simonutti, Kaloian Koynov, Simone Bonetti, Alberto Bianchi, Michael Kappl, Hans-Jürgen Butt, Ingo Lieberwirth, Michele Mauri, Bianchi, A, Mauri, M, Bonetti, S, Koynov, K, Kappl, M, Lieberwirth, I, Butt, H, and Simonutti, R

Subjects
Materials Chemistry2506 Metals and Alloy, Acrylamides, Materials science, Polymers and Plastics, Scanning electron microscope, Polymers, Block-copolymer, Organic Chemistry, Force spectroscopy, Nanoparticle, Self-assembly, Micelle, Chemical engineering, Transmission electron microscopy, Polymer chemistry, Materials Chemistry, Copolymer, Particle, Nanoparticles, Polystyrenes, Hierarchical structure
Abstract

The hierarchical self-assembly of an amphiphilic block copolymer, poly( N,N-dimethylacrylamide)-block-polystyrene with a very short hydrophilic block (PDMA10-b-PS62), in large granular nanoparticles is reported. While these nanoparticles are stable in water, their disaggregation can be induced either mechanically (i.e., by applying a force via the tip of the cantilever of an atomic force microscope (AFM)) or by partial hydrolysis of the acrylamide groups. AFM force spectroscopy images show the rupture of the particle as a combination of collapse and flow, while scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images of partly hydrolyzed nanoparticles provide a clear picture of the granular structure. (Chemical Equation Presented).

Published
2014

4. Sponge biosilica formation involves syneresis following polycondensation in vivo.

Author

Wang X, Schröder HC, Brandt D, Wiens M, Lieberwirth I, Glasser G, Schlossmacher U, Wang S, and Müller WE

Subjects
Animals, Aquaporins genetics, Cathepsins genetics, Gene Expression Regulation, Manganese Compounds metabolism, Silicon Dioxide chemistry, Spectroscopy, Fourier Transform Infrared, Suberites chemistry, Suberites genetics, Sulfates metabolism, Thermogravimetry, Water chemistry, Silicon Dioxide metabolism, Suberites metabolism, Suberites ultrastructure
Abstract

Syneresis is a process observed during the maturation/aging of silica gels obtained by sol-gel synthesis that results in shrinkage and expulsion of water due to a rearrangement and increase in the number of bridging siloxane bonds. Here we describe how the process of biosilica deposition during spicule ("biosilica" skeleton of the siliceous sponges) formation involves a phase of syneresis that occurs after the enzyme-mediated polycondensation reaction. Primmorphs from the demosponge Suberites domuncula were used to study syneresis and the inhibition of this mechanism. We showed by scanning electron microscopy that spicules added to primmorphs that have been incubated with manganese sulfate fuse together through the deposition of silica spheres and bridges. Energy-dispersive X-ray mapping of the newly formed deposits showed high silicon and oxygen content. These biosilica deposits contain a comparably higher percentage of water than mature/aged spicules. Quantitative real-time polymerase chain reaction analyses revealed that the addition of silicate to primmorph cultures resulted in a marked upregulation of the expression of the aquaporin gene and of the genes encoding the silica anabolic enzyme silicatein-α and the silica catabolic enzyme silicase. On the other hand, addition of manganese sulfate, either alone or together with silicate, caused a strong reduction in the level of aquaporin transcripts, although this metal ion did not essentially affect the silicate-induced increase in silicatein-α and silicase gene expression. We conclude that the secondary silica deposits formed on spicules under physiological conditions in the presence of silicate fuse together and subsequently undergo syneresis, which is facilitated by the removal of water through aquaporin channels. In growing spicules, these processes of biosilica formation and syneresis in the lamellar monolithic structures precede the final step of "biosintering" during which the massive biosilica rods of the spicules are formed., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Published
2011
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results