@article{SauterLuetzowSchossigetal.2012,
  author    = {Sauter, Tilman and L{\"u}tzow, Karola and Schossig, Michael and Kosmella, Hans and Weigel, Thomas and Kratz, Karl and Lendlein, Andreas},
  title     = {Shape-memory properties of polyetherurethane foams prepared by thermally induced phase separation},
  series = {Advanced engineering materials},
  volume    = {14},
  journal   = {Advanced engineering materials},
  number    = {9},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1438-1656},
  doi       = {10.1002/adem.201200127},
  pages     = {818 -- 824},
  year      = {2012},
  abstract  = {In this study, we report the preparation of two structurally different shape-memory polymer foams by thermally induced phase separation (TIPS) from amorphous polyetherurethanes. Foams with either a homogeneous, monomodal, or with a hierarchically structured, bimodal, pore size distribution are obtained by adoption of the cooling protocol. The shape-memory properties have been investigated for both foam structures by cyclic, thermomechanical experiments, while the morphological changes on the micro scale (pore level) have been compared to the macro scale by an in situ micro compression device experiment. The results show that the hierarchically structured foam achieves higher shape-recovery rates and a higher total recovery as compared to the homogeneous foam, which is due to an increased energy storage capability by micro scale bending of the hierarchically structured foam compared to pure compression of the homogeneous foam.},
  language  = {en}
}
@article{LuetzowWeigelLendlein2020,
  author    = {L{\"u}tzow, Karola and Weigel, Thomas and Lendlein, Andreas},
  title     = {Solvent-based fabrication method for magnetic, shape-memory nanocomposite foams},
  series = {MRS advances},
  volume    = {5},
  journal   = {MRS advances},
  number    = {14-15},
  publisher = {Cambridge Univ. Press},
  address   = {Cambridge},
  issn      = {2059-8521},
  doi       = {10.1557/adv.2019.422},
  pages     = {785 -- 795},
  year      = {2020},
  abstract  = {This paper presents shape-memory foams that can be temporarily fixed in their compressed state and be expanded on demand. Highly porous, nanocomposite foams were prepared from a solution of polyetherurethane with suspended nanoparticles (mean aggregate size 90 nm) which have an iron(III) oxide core with a silica shell. The polymer solution with suspended nanoparticles was cooled down to -20 degrees C in a two-stage process, which was followed by freeze-drying. The average pore size increases with decreasing concentration of nanoparticles from 158 mu m to 230 mu m while the foam porosity remained constant. After fixation of a temporary form of the nanocomposite foams, shape recovery can be triggered either by heat or by exposure to an alternating magnetic field. Compressed foams showed a recovery rate of up to 76 +/- 4\% in a thermochamber at 80 degrees C, and a slightly lower recovery rate of up to 65 +/- 4\% in a magnetic field.},
  language  = {en}
}