TY  - JOUR
A1  - Julich-Gruner, Konstanze K.
A1  - Löwenberg, Candy
A1  - Neffe, Axel T.
A1  - Behl, Marc
A1  - Lendlein, Andreas
T1  - Recent trends in the chemistry of shape-memory polymers
JF  - Macromolecular chemistry and physics
N2  - Shape-memory polymers (SMPs) are stimuli-sensitive materials capable of performing complex movements on demand, which makes them interesting candidates for various applications, for example, in biomedicine or aerospace. This trend article highlights current approaches in the chemistry of SMPs, such as tailored segment chemistry to integrate additional functions and novel synthetic routes toward permanent and temporary netpoints. Multiphase polymer networks and multimaterial systems illustrate that SMPs can be constructed as a modular system of different building blocks and netpoints. Future developments are aiming at multifunctional and multistimuli-sensitive SMPs.
KW  - multifunctional polymers
KW  - networks
KW  - shape-memory polymers
KW  - stimuli-sensitive polymers
KW  - triple-shape effect
Y1  - 2013
U6  - https://doi.org/10.1002/macp.201200607
SN  - 1022-1352
VL  - 214
IS  - 5
SP  - 527
EP  - 536
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - INPR
A1  - Julich-Gruner, Konstanze K.
A1  - Pandit, Abhay
A1  - Lendlein, Andreas
T1  - Advanced Functional Polymers Addressing the Needs of Modern Medicine
T2  - Macromolecular rapid communications
Y1  - 2015
U6  - https://doi.org/10.1002/marc.201500575
SN  - 1022-1336
SN  - 1521-3927
VL  - 36
IS  - 21
SP  - 1859
EP  - 1861
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Löwenberg, Candy
A1  - Tripodo, Giuseppe
A1  - Julich-Gruner, Konstanze K.
A1  - Neffe, Axel T.
A1  - Lendlein, Andreas
T1  - Supramolecular gelatin networks based on inclusion complexes
JF  - Macromolecular bioscience
N2  - Hydrogel forming physical networks based on gelatin are an attractive approach toward multifunctional biomaterials with the option of reshaping, self-healing, and stimuli-sensitivity. However, it is challenging to design such gelatin-based hydrogels to be stable at body temperature. Here, gelatin functionalized with desaminotyrosine (DAT) or desaminotyrosyl tyrosine (DATT) side chains is crosslinked with cyclodextrin (CD) dimers under formation of inclusions complexes. The supramolecular networks displayed at room temperature decreased water uptake (200-600 wt% for DAT-based systems, 200 wt% for DATT based systems), and increased storage moduli up to 25.6 kPa determined by rheology compared to DAT(T) gelatin. The gel-sol transition temperature increased from 33 up to 42 degrees C. The presented system that is completely based on natural building blocks may form the basis for materials that may potentially respond by dissolution or changes of properties to changes in environmental conditions or to the presence of CD guest molecules.
KW  - cyclodextrin
KW  - gelatin
KW  - inclusion complex
KW  - supramolecular polymer network
Y1  - 2020
U6  - https://doi.org/10.1002/mabi.202000221
SN  - 1616-5187
SN  - 1616-5195
VL  - 20
IS  - 10
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Neffe, Axel T.
A1  - Löwenberg, Candy
A1  - Julich-Gruner, Konstanze K.
A1  - Behl, Marc
A1  - Lendlein, Andreas
T1  - Thermally-induced shape-memory behavior of degradable gelatin-based networks
JF  - International journal of molecular sciences
N2  - Shape-memory hydrogels (SMH) are multifunctional, actively-moving polymers of interest in biomedicine. In loosely crosslinked polymer networks, gelatin chains may form triple helices, which can act as temporary net points in SMH, depending on the presence of salts. Here, we show programming and initiation of the shape-memory effect of such networks based on a thermomechanical process compatible with the physiological environment. The SMH were synthesized by reaction of glycidylmethacrylated gelatin with oligo(ethylene glycol) (OEG) alpha,omega-dithiols of varying crosslinker length and amount. Triple helicalization of gelatin chains is shown directly by wide-angle X-ray scattering and indirectly via the mechanical behavior at different temperatures. The ability to form triple helices increased with the molar mass of the crosslinker. Hydrogels had storage moduli of 0.27-23 kPa and Young's moduli of 215-360 kPa at 4 degrees C. The hydrogels were hydrolytically degradable, with full degradation to water-soluble products within one week at 37 degrees C and pH = 7.4. A thermally-induced shape-memory effect is demonstrated in bending as well as in compression tests, in which shape recovery with excellent shape-recovery rates R-r close to 100% were observed. In the future, the material presented here could be applied, e.g., as self-anchoring devices mechanically resembling the extracellular matrix.
KW  - shape-memory hydrogel
KW  - active polymer
KW  - biopolymer
KW  - mechanical
KW  - properties
KW  - degradation
Y1  - 2021
U6  - https://doi.org/10.3390/ijms22115892
SN  - 1422-0067
SN  - 1661-6596
VL  - 22
IS  - 11
PB  - Molecular Diversity Preservation International
CY  - Basel
ER  -