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 - Behl, Marc A1 - Razzaq, Muhammad Yasar A1 - Mazurek-Budzynska, Magdalena A1 - Lendlein, Andreas T1 - Polyetheresterurethane based porous scaffolds with tailorable architectures by supercritical CO2 foaming JF - MRS advances N2 - Porous three-dimensional (3D) scaffolds are promising treatment options in regenerative medicine. Supercritical and dense-phase fluid technologies provide an attractive alternative to solvent-based scaffold fabrication methods. In this work, we report on the fabrication of poly-etheresterurethane (PPDO-PCL) based porous scaffolds with tailorable pore size, porosity, and pore interconnectivity by using supercritical CO2(scCO(2)) fluid-foaming. The influence of the processing parameters such as soaking time, soaking temperature and depressurization on porosity, pore size, and interconnectivity of the foams were investigated. The average pore diameter could be varied between 100-800 mu m along with a porosity in the range from (19 +/- 3 to 61 +/- 6)% and interconnectivity of up to 82%. To demonstrate their applicability as scaffold materials, selected foams were sterilized via ethylene oxide sterilization. They showed negligible cytotoxicity in tests according to DIN EN ISO 10993-5 and 10993-12 using L929 cells. The study demonstrated that the pore size, porosity and the interconnectivity of this multi-phase semicrystalline polymer could be tailored by careful control of the processing parameters during the scCO(2)foaming process. In this way, PPDO-PCL scaffolds with high porosity and interconnectivity are potential candidate materials for regenerative treatment options. Y1 - 2020 U6 - https://doi.org/10.1557/adv.2020.345 SN - 2059-8521 VL - 5 IS - 45 SP - 2317 EP - 2330 PB - Cambridge University Press CY - New York, NY ER - 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 - JOUR A1 - Tartivel, Lucile A1 - Behl, Marc A1 - Schröter, Michael A1 - Lendlein, Andreas T1 - Hydrogel networks based on ABA triblock copolymers JF - Journal of applied biomaterials & functional materials N2 - Background: Triblock copolymers from hydrophilic oligo(ethylene glycol) segment A and oligo(propylene glycol) segment B, providing an ABA structure (OEG-OPG-OEG triblock), are known to be biocompatible and are used as self-solidifying gels in drug depots. A complete removal of these depots would be helpful in cases of undesired side effects of a drug, but this remains a challenge as they liquefy below their transition temperature. Therefore we describe the synthesis of covalently cross-linked hydrogel networks. Method: Triblock copolymer-based hydrogels were created by irradiating aqueous solutions of the corresponding macro-dimethacrylates with UV light. The degree of swelling, swelling kinetics, mechanical properties and morphology of the networks were investigated. Results: Depending on precursor concentration, equilibrium degree of swelling of the films ranged between 500% and 880% and was reached in 1 hour. In addition, values for storage and loss moduli of the hydrogel networks were in the 100 Pa to 10 kPa range. Conclusion: Although OEG-OPG-OEG triblocks are known for their micellization, which could hamper polymer network formation, reactive OEG-OPG-OEG triblock oligomers could be successfully polymerized into hydrogel networks. The degree of swelling of these hydrogels depends on their molecular weight and on the oligomer concentration used for hydrogel preparation. In combination with the temperature sensitivity of the ABA triblock copolymers, it is assumed that such hydrogels might be beneficial for future medical applications -e.g., removable drug release systems. KW - Hydrogel KW - Rheological characterization KW - Oligo(ethylene glycol) derivatization KW - OEG-OPG-OEG triblock copolymer KW - UV crosslinking Y1 - 2012 U6 - https://doi.org/10.5301/JABFM.2012.10295 SN - 2280-8000 VL - 10 IS - 3 SP - 243 EP - 248 PB - Wichtig CY - Milano ER -