TY  - JOUR
A1  - Diehl, Christina
A1  - Cernoch, Peter
A1  - Zenke, Ingrid
A1  - Runge, Heike
A1  - Pitschke, Rona
A1  - Hartmann, Juergen
A1  - Tiersch, Brigitte
A1  - Schlaad, Helmut
T1  - Mechanistic study of the phase separation/crystallization process of poly(2-isopropyl-2-oxazoline) in hot water
N2  - The kinetics of the crystallization of thermoresponsive poly(2-isopropyl-2-oxazoline) in water and the time- dependent evolution of the morphology were examined using wide-angle X-ray scattering and conventional and cryogenic scanning electron microscopy. Results indicate that a temperature-induced phase separation produces a bicontinuous polymer network-like structure, which with the onset of crystallization collapses into individual particles (1-2 mu m in diameter) composed of a porous fiber mesh. Nanofibers then preferentially form at the particle surface, thus wrapping the microspheres like a ball of wool. The particle morphology is severely affected by changes in temperature and less by the initial polymer concentration.
Y1  - 2010
UR  - http://www.rsc.org/Publishing/Journals/sm/index.asp
U6  - https://doi.org/10.1039/C0sm00114g
SN  - 1744-683X
ER  - 
TY  - JOUR
A1  - Sun, Jing
A1  - Cernoch, Peter
A1  - Völkel, Antje
A1  - Wei, Yuhan
A1  - Ruokolainen, Janne
A1  - Schlaad, Helmut
T1  - Aqueous Self-Assembly of a Protein-Mimetic Ampholytic Block Copolypeptide
JF  - Macromolecules : a publication of the American Chemical Society
N2  - This report describes the aggregation behavior of an ABC-type ampholytic block copolypeptide, poly(ethylene oxide)-block-poly(L-lysine)-block-poly(L-glutamate), in aqueous media in dependence of pH. Polypeptide secondary structures and self-assemblies are investigated by circular dichroism (CD), Fourier transform infrared (FT-IR) and NMR spectroscopy, zeta potential measurements, analytical ultracentrifugation (AUC), dynamic/static light scattering (DLS/SLS), and cryogenic transmission electron microscopy (cryoTEM). The polymer chains tend to form vesicles when the hydrophobic polypeptide helix is located at the chain end (acidic pH) and are existing as single chains when it is located in the center and flanked by the two hydrophilic segments (basic pH). Precipitation occurs in the intermediate pH range due to polyion complexation of the charged polypeptide segments.
Y1  - 2016
U6  - https://doi.org/10.1021/acs.macromol.6b00817
SN  - 0024-9297
SN  - 1520-5835
VL  - 49
SP  - 5494
EP  - 5501
PB  - American Chemical Society
CY  - Washington
ER  -