@misc{NoechelReddyWangetal.2015,
  author    = {N{\"o}chel, Ulrich and Reddy, Chaganti Srinivasa and Wang, Ke and Cui, Jing and Zizak, Ivo and Behl, Marc and Kratz, Karl and Lendlein, Andreas},
  title     = {Nanostructural changes in crystallizable controlling units determine the temperature-memory of polymers},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-81124},
  pages     = {8284 -- 8293},
  year      = {2015},
  abstract  = {Temperature-memory polymers remember the temperature, where they were deformed recently, enabled by broad thermal transitions. In this study, we explored a series of crosslinked poly[ethylene-co-(vinyl acetate)] networks (cPEVAs) comprising crystallizable polyethylene (PE) controlling units exhibiting a pronounced temperature-memory effect (TME) between 16 and 99 °C related to a broad melting transition (∼100 °C). The nanostructural changes in such cPEVAs during programming and activation of the TME were analyzed via in situ X-ray scattering and specific annealing experiments. Different contributions to the mechanism of memorizing high or low deformation temperatures (Tdeform) were observed in cPEVA, which can be associated to the average PE crystal sizes. At high deformation temperatures (>50 °C), newly formed PE crystals, which are established during cooling when fixing the temporary shape, dominated the TME mechanism. In contrast, at low Tdeform (<50 °C), corresponding to a cold drawing scenario, the deformation led preferably to a disruption of existing large crystals into smaller ones, which then fix the temporary shape upon cooling. The observed mechanism of memorizing a deformation temperature might enable the prediction of the TME behavior and the knowledge based design of other TMPs with crystallizable controlling units.},
  language  = {en}
}
@article{NoechelReddyWangetal.2015,
  author    = {N{\"o}chel, Ulrich and Reddy, Chaganti Srinivasa and Wang, Ke and Cui, Jing and Zizak, Ivo and Behl, Marc and Kratz, Karl and Lendlein, Andreas},
  title     = {Nanostructural changes in crystallizable controlling units determine the temperature-memory of polymers},
  series = {Journal of Materials Chemistry A, Materials for energy and sustainability},
  volume    = {16},
  journal   = {Journal of Materials Chemistry A, Materials for energy and sustainability},
  number    = {3},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {2050-7488},
  doi       = {10.1039/c4ta06586g},
  pages     = {8284 -- 8293},
  year      = {2015},
  abstract  = {Temperature-memory polymers remember the temperature, where they were deformed recently, enabled by broad thermal transitions. In this study, we explored a series of crosslinked poly[ethylene-co-(vinyl acetate)] networks (cPEVAs) comprising crystallizable polyethylene (PE) controlling units exhibiting a pronounced temperature-memory effect (TME) between 16 and 99 °C related to a broad melting transition (∼100 °C). The nanostructural changes in such cPEVAs during programming and activation of the TME were analyzed via in situ X-ray scattering and specific annealing experiments. Different contributions to the mechanism of memorizing high or low deformation temperatures (Tdeform) were observed in cPEVA, which can be associated to the average PE crystal sizes. At high deformation temperatures (>50 °C), newly formed PE crystals, which are established during cooling when fixing the temporary shape, dominated the TME mechanism. In contrast, at low Tdeform (<50 °C), corresponding to a cold drawing scenario, the deformation led preferably to a disruption of existing large crystals into smaller ones, which then fix the temporary shape upon cooling. The observed mechanism of memorizing a deformation temperature might enable the prediction of the TME behavior and the knowledge based design of other TMPs with crystallizable controlling units.},
  language  = {en}
}
@article{WangKratzBehletal.2015,
  author    = {Wang, Weiwei and Kratz, Karl and Behl, Marc and Yan, Wan and Liu, Yue and Xu, Xun and Baudis, Stefan and Li, Zhengdong and Kurtz, Andreas and Lendlein, Andreas and Ma, Nan},
  title     = {The interaction of adipose-derived human mesenchymal stem cells and polyether ether ketone},
  series = {Clinical hemorheology and microcirculation : blood flow and vessels},
  volume    = {61},
  journal   = {Clinical hemorheology and microcirculation : blood flow and vessels},
  number    = {2},
  publisher = {IOS Press},
  address   = {Amsterdam},
  issn      = {1386-0291},
  doi       = {10.3233/CH-152001},
  pages     = {301 -- 321},
  year      = {2015},
  abstract  = {Polyether ether ketone (PEEK) as a high-performance, thermoplastic implant material entered the field of medical applications due to its structural function and commercial availability. In bone tissue engineering, the combination of mesenchymal stem cells (MSCs) with PEEK implants may accelerate the bone formation and promote the osseointegration between the implant and the adjacent bone tissue. In this concept the question how PEEK influences the behaviour and functions of MSCs is of great interest. Here the cellular response of human adipose-derived MSCs to PEEK was evaluated and compared to tissue culture plate (TCP) as the reference material. Viability and morphology of cells were not altered when cultured on the PEEK film. The cells on PEEK presented a high proliferation activity in spite of a relatively lower initial cell adhesion rate. There was no significant difference on cell apoptosis and senescence between the cells on PEEK and TCP. The inflammatory cytokines and VEGF secreted by the cells on these two surfaces were at similar levels. The cells on PEEK showed up-regulated BMP2 and down-regulated BMP4 and BMP6 gene expression, whereas no conspicuous differences were observed in the committed osteoblast markers (BGLAP, COL1A1 and Runx2). With osteoinduction the cells on PEEK and TCP exhibited a similar osteogenic differentiation potential. Our results demonstrate the biofunctionality of PEEK for human MSC cultivation and differentiation. Its clinical benefits in bone tissue engineering may be achieved by combining MSCs with PEEK implants. These data may also provide useful information for further modification of PEEK with chemical or physical methods to regulate the cellular processes of MSCs and to consequently improve the efficacy of MSC-PEEK based therapies.},
  language  = {en}
}
@article{NoechelReddyWangetal.2015,
  author    = {N{\"o}chel, Ulrich and Reddy, Chaganti Srinivasa and Wang, Ke and Cui, Jing and Zizak, Ivo and Behl, Marc and Kratz, Karl and Lendlein, Andreas},
  title     = {Nanostructural changes in crystallizable controlling units determine the temperature-memory of polymers},
  series = {Journal of materials chemistry : A, Materials for energy and sustainability},
  volume    = {3},
  journal   = {Journal of materials chemistry : A, Materials for energy and sustainability},
  number    = {16},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {2050-7488},
  doi       = {10.1039/c4ta06586g},
  pages     = {8284 -- 8293},
  year      = {2015},
  abstract  = {Temperature-memory polymers remember the temperature, where they were deformed recently, enabled by broad thermal transitions. In this study, we explored a series of crosslinked poly[ethylene-co-(vinyl acetate)] networks (cPEVAs) comprising crystallizable polyethylene (PE) controlling units exhibiting a pronounced temperature-memory effect (TME) between 16 and 99 degrees C related to a broad melting transition (similar to 100 degrees C). The nanostructural changes in such cPEVAs during programming and activation of the TME were analyzed via in situ X-ray scattering and specific annealing experiments. Different contributions to the mechanism of memorizing high or low deformation temperatures (T-deform) were observed in cPEVA, which can be associated to the average PE crystal sizes. At high deformation temperatures (>50 degrees C), newly formed PE crystals, which are established during cooling when fixing the temporary shape, dominated the TME mechanism. In contrast, at low T-deform (<50 degrees C), corresponding to a cold drawing scenario, the deformation led preferably to a disruption of existing large crystals into smaller ones, which then fix the temporary shape upon cooling. The observed mechanism of memorizing a deformation temperature might enable the prediction of the TME behavior and the knowledge based design of other TMPs with crystallizable controlling units.},
  language  = {en}
}
@article{SaatchiBehlNoecheletal.2015,
  author    = {Saatchi, Mersa and Behl, Marc and N{\"o}chel, Ulrich and Lendlein, Andreas},
  title     = {Copolymer Networks From Oligo(epsilon-caprolactone) and n-Butyl Acrylate Enable a Reversible Bidirectional Shape-Memory Effect at Human Body Temperature},
  series = {Macromolecular rapid communications},
  volume    = {36},
  journal   = {Macromolecular rapid communications},
  number    = {10},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1022-1336},
  doi       = {10.1002/marc.201400729},
  pages     = {880 -- 884},
  year      = {2015},
  abstract  = {Exploiting the tremendous potential of the recently discovered reversible bidirectional shape-memory effect (rbSME) for biomedical applications requires switching temperatures in the physiological range. The recent strategy is based on the reduction of the melting temperature range (T-m) of the actuating oligo(epsilon-caprolactone) (OCL) domains in copolymer networks from OCL and n-butyl acrylate (BA), where the reversible effect can be adjusted to the human body temperature. In addition, it is investigated whether an rbSME in the temperature range close or even above T-m,T-offset (end of the melting transition) can be obtained. Two series of networks having mixtures of OCLs reveal broad T(m)s from 2 degrees C to 50 degrees C and from -10 degrees C to 37 degrees C, respectively. In cyclic, thermomechanical experiments the rbSME can be tailored to display pronounced actuation in a temperature interval between 20 degrees C and 37 degrees C. In this way, the application spectrum of the rbSME can be extended to biomedical applications.},
  language  = {en}
}