TY  - GEN
A1  - Hentrich, Doreen
A1  - Junginger, Mathias
A1  - Bruns, Michael
A1  - Börner, Hans Gerhard
A1  - Brandt, Jessica
A1  - Brezesinski, Gerald
A1  - Taubert, Andreas
T1  - Interface-controlled calcium phosphate mineralization
BT  - effect of oligo(aspartic acid)-rich interfaces
N2  - The phase behavior of an amphiphilic block copolymer based on a poly(aspartic acid) hydrophilic block and a poly(n-butyl acrylate) hydrophobic block was investigated at the air–water and air–buffer interface. The polymer forms stable monomolecular films on both subphases. At low pH, the isotherms exhibit a plateau. Compression–expansion experiments and infrared reflection absorption spectroscopy suggest that the plateau is likely due to the formation of polymer bi- or multilayers. At high pH the films remain intact upon compression and no multilayer formation is observed. Furthermore, the mineralization of calcium phosphate beneath the monolayer was studied at different pH. The pH of the subphase and thus the polymer charge strongly affects the phase behavior of the film and the mineral formation. After 4 h of mineralization at low pH, atomic force microscopy shows smooth mineral films with a low roughness. With increasing pH the mineral films become inhomogeneous and the roughness increases. Transmission electron microscopy confirms this: at low pH a few small but uniform particles form whereas particles grown at higher pH are larger and highly agglomerated. Energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy confirm the formation of calcium phosphate. The levels of mineralization are higher in samples grown at high pH.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 213 
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-89540
SP  - 6901
EP  - 6913
ER  - 
TY  - GEN
A1  - Junginger, Mathias
A1  - Kübel, Christian
A1  - Schacher, Felix H.
A1  - Müller, Axel H. E.
A1  - Taubert, Andreas
T1  - Crystal structure and chemical composition of biomimetic calcium phosphate nanofibers
N2  - 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.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 244 
KW  - air-water-interface
KW  - polycationic monolayer
KW  - mineralization beneath
KW  - block-copolymers
KW  - aqueous-solution
KW  - morphology
KW  - orthophosphates
KW  - biomaterials
KW  - nucleation
KW  - clusters
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-95176
SP  - 11301
EP  - 11308
ER  -