TY  - JOUR
A1  - Yan, Wan
A1  - Fang, Liang
A1  - Nöchel, Ulrich
A1  - Gould, Oliver E. C.
A1  - Behl, Marc
A1  - Kratz, Karl
A1  - Lendlein, Andreas
T1  - Investigating the roles of crystallizable and glassy switching segments within multiblock copolymer shape-memory materials
JF  - MRS Advances
N2  - The variation of the molecular architecture of multiblock copolymers has enabled the introduction of functional behaviour and the control of key mechanical properties. In the current study, we explore the synergistic relationship of two structural components in a shape-memory material formed of a multiblock copolymer with crystallizable poly(epsilon-caprolactone) and crystallizable polyfoligo(3S-iso-butylmorpholine-2,5-dione) segments (PCL-PIBMD). The thermal and structural properties of PCL-PIBMD films were compared with PCI.-PU and PMMD-PU investigated by means of DSC, SAXS and WARS measurements. The shape-memory properties were quantified by cyclic, thermomechanical tensile tests, where deformation strains up to 900% were applied for programming PCL-PIBMD films at 50 degrees C. Toluene vapor treatment experiments demonstrated that the temporary shape was fixed mainly by glassy PIBMD domains at strains lower than 600% with the PCL contribution to fixation increasing to 42 +/- 2% at programming strains of 900% This study into the shape-memory mechanism of PCL-PIBMD provides insight into the structure function relation in multiblock copolymers with both crystallizable and glassy switching segments.
Y1  - 2018
U6  - https://doi.org/10.1557/adv.2018.590
SN  - 2059-8521
VL  - 3
IS  - 63
SP  - 3741
EP  - 3749
PB  - Cambridge Univ. Press
CY  - New York
ER  - 
TY  - CHAP
A1  - Behl, Marc
A1  - Kratz, Karl
A1  - Nöchel, Ulrich
A1  - Sauter, Tilman
A1  - Lendlein, Andreas
T1  - Polymer networks capable of reversible shape-memory-effects
T2  - Abstracts of papers : joint conference / The Chemical Institute of Cananda, CIC, American Chemical Society, ACS
Y1  - 2014
SN  - 0065-7727
VL  - 248
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Zaupa, Alessandro
A1  - Neffe, Axel T.
A1  - Pierce, Benjamin F.
A1  - Nöchel, Ulrich
A1  - Lendlein, Andreas
T1  - Influence of tyrosine-derived moieties and drying conditions on the formation of helices in gelatin
JF  - Biomacromolecules : an interdisciplinary journal focused at the interface of polymer science and the biological sciences
N2  - The single and triple helical organization of protein chains strongly influences the mechanical properties of gelatin-based materials. A chemical method for obtaining different degrees of helical organization in gelatin is covalent functionalization, while a physical method for achieving the same goal is the variation of the drying conditions of gelatin solutions. Here we explored how the introduction of desaminotyrosine (DAT) and desaminotyrosyl tyrosine (DATT) linked to lysine residues of gelatin influenced the kinetics and thermodynamic equilibrium of the helicalization process of single and triple helices following different drying conditions. Drying at a temperature above. the helix-to-coil transition temperature of gelatin (T > T-c, called nu(short)) generally resulted in gelatins with relatively lower triple helical content (X-c,X-t = 1-2%) than lower temperature drying (T < T-c, called nu(long)) (X-c,X-t = 8-10%), where the DAT(T) functional groups generally disrupted helix formation. While different helical contents affected the thermal transition temperatures only slightly, the mechanical properties were strongly affected for swollen hydrogels (E = 4-13 kPa for samples treated by nu(long) and E = 120-700 kPa for samples treated by nu(short)). This study shows that side group functionalization and different drying conditions are viable options to control the helicalization and macroscopic properties of gelatin-based materials.
Y1  - 2011
U6  - https://doi.org/10.1021/bm101029k
SN  - 1525-7797
VL  - 12
IS  - 1
SP  - 75
EP  - 81
PB  - American Chemical Society
CY  - Washington
ER  -