03 Fakultät Chemie

Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/4

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    Piezoelectric templates - new views on biomineralization and biomimetics
    (2016) Stitz, Nina; Eiben, Sabine; Atanasova, Petia; Domingo, Neus; Leineweber, Andreas; Burghard, Zaklina; Bill, Joachim
    Biomineralization in general is based on electrostatic interactions and molecular recognition of organic and inorganic phases. These principles of biomineralization have also been utilized and transferred to bio-inspired synthesis of functional materials during the past decades. Proteins involved in both, biomineralization and bio-inspired processes, are often piezoelectric due to their dipolar character hinting to the impact of a template’s piezoelectricity on mineralization processes. However, the piezoelectric contribution on the mineralization process and especially the interaction of organic and inorganic phases is hardly considered so far. We herein report the successful use of the intrinsic piezoelectric properties of tobacco mosaic virus (TMV) to synthesize piezoelectric ZnO. Such films show a two-fold increase of the piezoelectric coefficient up to 7.2 pm V−1 compared to films synthesized on non-piezoelectric templates. By utilizing the intrinsic piezoelectricity of a biotemplate, we thus established a novel synthesis pathway towards functional materials, which sheds light on the whole field of biomimetics. The obtained results are of even broader and general interest since they are providing a new, more comprehensive insight into the mechanisms involved into biomineralization in living nature.
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    A complementary experimental and theoretical approach for probing the surface functionalization of ZnO with molecular catalyst linkers
    (2023) Kousik, Shravan R.; Solodenko, Helena; YazdanYar, Azade; Kirchhof, Manuel; Schützendübe, Peter; Richter, Gunther; Laschat, Sabine; Fyta, Maria; Schmitz, Guido; Bill, Joachim; Atanasova, Petia
    The application of ZnO materials as solid-state supports for molecular heterogeneous catalysis is contingent on the functionalization of the ZnO surface with stable self-assembled monolayers (SAMs) of catalyst linker molecules. Herein, experimental and theoretical methods are used to study SAMs of azide-terminated molecular catalyst linkers with two different anchor groups (silane and thiol) on poly and monocrystalline (0001, ) ZnO surfaces. Angle-resolved and temperature-dependent X-ray photoelectron spectroscopy (XPS) is used to study SAM binding modes, thermal stabilities, and coverages. The binding strengths and atomistic ordering of the SAMs are determined via atom-probe tomography (APT). Density functional theory (DFT) and ab initio molecular dynamics (AIMD) calculations provide insights on the influence of the ZnO surface polarity on the interaction affinity and conformational behavior of the SAMs. The investigations show that SAMs based on 3-azidopropyltriethoxysilane possess a higher binding strength and thermal stability than the corresponding thiol. SAM surface coverage is strongly influenced by the surface polarity of ZnO, and the highest coverage is observed on the polycrystalline surface. To demonstrate the applicability of linker-modified polycrystalline ZnO as a catalyst support, a chiral Rh diene complex is immobilized on the azide-terminal of the SAM and its coverage is evaluated via XPS.