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Author: Mayr, Stefan G. × DDC: 670 ×

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    Tailoring morphology in titania nanotube arrays by implantation: experiments and modelling on designed pore size—and beyond
    (London [u.a.] : Taylor & Francis, 2021) Kupferer, Astrid; Mändl, Stephan; Mayr, Stefan G.
    Titania nanotube arrays are an exceptionally adaptable material for various applications ranging from energy conversion to biomedicine. Besides electronic properties, structural morphology on nanometre scale is essential. It is demonstrated that ion implantation constitutes a versatile method for the synthesis of tailored nanotube morphologies. Experimental-phenomenological observations reveal a successive closing behaviour of nanotubes upon ion implantation. Employing molecular dynamics calculations in combination with analytical continuum models, the physical origins of this scenario are unravelled by identifying ion bombardment induced viscous flow driven by capillarity as its underlying mechanism besides minor contributions from sputtering and redeposition. These findings enable the tailoring of nanotube arrays suitable for manifold applications.
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    Collagen-iron oxide nanoparticle based ferrogel: Large reversible magnetostrains with potential for bioactuation
    (Bristol : IOP Publishing, 2020) Jauch, Philine; Weidner, Andreas; Riedel, Stefanie; Wilharm, Nils; Dutz, Silvio; Mayr, Stefan G.
    Smart materials such as stimuli responsive polymeric hydrogels offer unique possibilities for tissue engineering and regenerative medicine. As, however, most synthetic polymer systems and their degradation products lack complete biocompatibility and biodegradability, this study aims to synthesize a highly magnetic responsive hydrogel, based on the abundant natural biopolymer collagen. As the main component of vertebratal extracellular matrix, it reveals excellent biocompatibility. In combination with incorporated magnetic iron oxide nanoparticles, a novel smart nano-bio-ferrogel can be designed. While retaining its basic biophysical properties and interaction with living cells, this collagen-nanoparticle hydrogel can be compressed to 38% of its original size and recovers to 95% in suitable magnetic fields. Besides the phenomenology of this scenario, the underlying physical scenarios are also discussed within the framework of network models. The observed reversible peak strains as large as 150% open up possibilities for the fields of biomedical actuation, soft robotics and beyond. © 2020 The Author(s). Published by IOP Publishing Ltd