TY - JOUR A1 - Droste, Bernhard A1 - Maitra, A. N. A1 - Hecht, A. A1 - Feiler, H. G. T1 - Das anodische Verhalten von Nickel bei Zusatz von Thioharnstoff und Dicyandiamid PY - 1979 SN - 0026-0797 SN - 0043-2792 VL - 33 IS - 3 SP - 112 EP - 120 PB - IGT, Informationsges. Technik CY - München AN - OPUS4-9049 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kathan, M. A1 - Kovaricek, P. A1 - Jurissek, Ch. A1 - Senf, A. A1 - Dallmann, A. A1 - Thünemann, Andreas A1 - Hecht, S. T1 - Control of Imine Exchange Kinetics with Photoswitches to Modulate Self-Healing in Polysiloxane Networks by Light Illumination N2 - Various aldehyde-containing photoswitches have been developed whose reactivity toward amines can be controlled externally. A thermally stable bifunctional diarylethene, which in its ring-closed form exhibits imine formation accelerated by one order of magnitude, was used as a photoswitchable crosslinker and mixed with a commercially available amino-functionalized polysiloxane to yield a rubbery material with viscoelastic and self-healing properties that can be reversibly tuned by irradiation. KW - Polymer KW - Self-healing KW - Rheology KW - Nanotechnology PY - 2016 DO - https://doi.org/10.1002/anie.201605311 SN - 1433-7851 (print) SN - 1521-3773 (online) VL - 55 IS - 44 SP - 13882 EP - 13886 PB - Wiley-VCH Verlag GmbH CY - Weinheim AN - OPUS4-37904 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Eisenreich, F. A1 - Kathan, M. A1 - Dallmann, A. A1 - Ihrig, S. P. A1 - Schwaar, Timm A1 - Schmidt, B. M. A1 - Hecht, S. T1 - A photoswitchable catalyst system for remote-controlled (co)polymerization in situ N2 - The fundamental properties of a polymeric material are ultimately governed by its structure, which mainly relies on monomercomposition and connection, topology, chain length, and polydispersity. Thus far, these structural characteristics are typicallyset ex situ by the specific polymerization procedure, eventually limiting the future design space for the creation of moresophisticated polymers. Herein, we report on a single photoswitchable catalyst system, which enables in situ remote controlover the ring-opening polymerization of l-lactide and further allows regulation of the incorporation of trimethylene carbonateand δ -valerolactone monomers in copolymerizations. By implementing a phenol moiety into a diarylethene-type structure,we exploit light-induced keto–enol tautomerism to switch the hydrogen-bonding-mediated monomer activation reversiblyON and OFF. This general and versatile principle allows for exquisite external modulation of ground-state catalysis of a livingpolymerization process in a closed system by ultraviolet and visible light and should thereby facilitate the generation of newpolymer structures. KW - Polymers PY - 2018 DO - https://doi.org/10.1038/s41929-018-0091-8 SN - 2520-1158 VL - 1 IS - 7 SP - 516 EP - 522 PB - Nature CY - London AN - OPUS4-45407 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hecht, A. A1 - Thiel, R. A1 - Funck, B. A1 - Neumann, Eberhard A1 - Mundry, Eberhard T1 - Konzeption, Aufbau und Arbeitsweise eines rechnergesteuerten Ultraschallmeßplatzes, dargestellt am Beispiel der Gefügeuntersuchung an austenitischen Rohren T2 - 2. Europäische Tagung für Zerstörungsfreie Prüfung CY - Wien DA - 1981-09-14 PY - 1981 SP - 280 EP - 281 CY - Wien AN - OPUS4-33310 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hecht, A. A1 - Mundry, Eberhard A1 - Nabel, Eberhard A1 - Neumann, Eberhard T1 - Korngrößenbestimmung in austenitischen Feinblechen mit Ultraschall T2 - Europäische Tagung für Zerstörungsfreie Materialprüfung CY - Mainz, Deutschland DA - 1978-04-24 PY - 1978 VL - 2 SP - 395 EP - 402 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung CY - Berlin AN - OPUS4-8983 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hecht, A. A1 - Thiel, R. A1 - Nabel, Eberhard A1 - Neumann, Eberhard A1 - Mundry, Eberhard T1 - Zerstörungsfreie Korngrößenbestimmung an austenitischen Feinblechen mit Hilfe der Ultraschallrückstreuung PY - 1979 SN - 0340-7551 VL - 9 IS - 3 SP - 110 EP - 111 PB - Bundesanstalt für Materialprüfung CY - Berlin AN - OPUS4-9178 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hecht, A. A1 - Thiel, R. A1 - Neumann, Eberhard A1 - Nabel, Eberhard A1 - Mundry, Eberhard T1 - Einsatz und Erprobung eines Meßverfahrens zur Korngrößenbestimmung an austenitischen Feinblechen mit Hilfe der Ultraschallrückstreuung PY - 1979 SN - 0025-5300 VL - 21 IS - 8 SP - 275 EP - 276 PB - Carl Hanser Verlag CY - München AN - OPUS4-9179 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Neumann, Eberhard A1 - Hecht, A. A1 - Thiel, R. A1 - Nabel, Eberhard A1 - Mundry, Eberhard T1 - Determination of the grain size of austenitic sheet by ultrasonic backscattering during the rolling process T2 - 9th World Conference on Nondestructive Testing CY - Melbourne, Australia DA - 1979-11-19 PY - 1979 SP - 1 EP - 7(?) CY - Cannes AN - OPUS4-9185 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hecht, A. A1 - Neumann, Eberhard A1 - Mundry, Eberhard A1 - Thiel, R. T1 - Probleme der Korngrößenbestimmung an austenitischen Bändern mit Hilfe der Ultraschallrückstreuung T2 - Internationales Symposium ; International symposium CY - Saarbrücken, Deutschland DA - 1979-09-17 PY - 1980 SP - 221 EP - 228 CY - Berlin AN - OPUS4-9413 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thiel, R. A1 - Nabel, Eberhard A1 - Hecht, A. A1 - Neumann, Eberhard A1 - Mundry, Eberhard T1 - Zerstörungsfreie Korngrößenbestimmung an austenitischen Feinblechen mit Hilfe der Ultraschallrückstreuung T2 - 1. Najnovejsi dosezki na podrocju preiskav materiala brez porusitve CY - Krsko, Jugoslawien DA - 1979-09-05 PY - 1979 SP - 1(?) EP - 9(?) CY - Krsko AN - OPUS4-16178 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mutruc, D. A1 - Goulet-Hanssens, A. A1 - Fairmann, S. A1 - Wahl, S. A1 - Zimathies, Annett A1 - Knie, C. A1 - Hecht, S. T1 - Modulating Guest Uptake in Core-Shell MOFs with Visible Light N2 - A two-component core-shell UiO-68 type metal-organic framework (MOF) with a nonfunctionalized interior for efficient guest uptake and storage and a thin light-responsive outer shell was prepared by initial solvothermal MOF synthesis followed by solvent-assisted linker exchange. The bulky shell linker features two tetra-ortho-fluorinated azobenzene moieties to exploit their advantageous photoisomerization properties. The obtained perfect octahedral MOF single crystals can be switched repeatedly and with an unprecedented efficiency between E- and Z-rich states using visible light only. Due to the high photoswitch density per pore of the shell layer, its steric demand and thus molecular uptake (and release) can be conveniently modulated upon green and blue light irradiation. Therefore, the "smart" shell acts as a light-controlled kinetic barrier or "gate" for the diffusion of cargo molecules in and out of the MOF crystals. KW - Visible light KW - Azobenzene KW - Guest uptake/release KW - Metal– organic frameworks KW - Photochromism PY - 2019 DO - https://doi.org/10.1002/anie.201906606 VL - 58 SP - 12862 EP - 12867 PB - WILEY-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-48941 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fuhrmann, A. A1 - Göstl, R. A1 - Wendt, R. A1 - Kötteritzsch, J. A1 - Hager, M. D. A1 - Schubert, U. S. A1 - Brademann-Jock, Kerstin A1 - Thünemann, Andreas A1 - Nöchel, U. A1 - Behl, M. A1 - Hecht, S. T1 - Conditional repair by locally switching the thermal healing capability of dynamic covalent polymers with light N2 - Healable materials could play an important role in reducing the environmental footprint of our modern technological society through extending the life cycles of consumer products and constructions. However, as most healing processes are carried out by heat alone, the ability to heal damage generally kills the parent material’s thermal and mechanical properties. Here we present a dynamic covalent polymer network whose thermal healing ability can be switched ‘on’ and ‘off’ on demand by light, thereby providing local control over repair while retaining the advantageous macroscopic properties of static polymer networks. We employ a photoswitchable furan-based crosslinker, which reacts with short and mobile maleimidesubstituted poly(lauryl methacrylate) chains forming strong covalent bonds while simultaneously allowing the reversible, spatiotemporally resolved control over thermally induced de- and re-crosslinking. We reason that our system can be adapted to more complex materials and has the potential to impact applications in responsive coatings, photolithography and microfabrication. KW - Small-angle X-ray scattering KW - SAXS KW - Polymer PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-386689 DO - https://doi.org/10.1038/ncomms13623 SN - 2041-1723 VL - 7 SP - Article 13623, 1 EP - 7 PB - NATURE PUBLISHING GROUP CY - MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND AN - OPUS4-38668 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gille, M. A1 - Viertel, A. A1 - Weidner, Steffen A1 - Hecht, S. T1 - Modular synthesis of monomers for on-surface polymerization to graphene architectures N2 - We developed a modular synthesis of halogenated polycyclic aromatic monomers for on-surface polymerization to generate graphene wires, ribbons, and networks. KW - Graphene monomers KW - Graphene nanoribbons KW - Functionalized graphene nanoribbons KW - Graphene wires KW - Hexabenzocoronene KW - On-surface polymerization PY - 2013 DO - https://doi.org/10.1055/s-0032-1317959 SN - 0936-5214 SN - 1437-2096 VL - 24 IS - 2 SP - 0259 EP - 0263 PB - Thieme CY - Stuttgart AN - OPUS4-27621 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - El Malah, T. A1 - Ciesielski, A. A1 - Piot, L. A1 - Troyanov, S.I. A1 - Mueller, U. A1 - Weidner, Steffen A1 - Samorì, P. A1 - Hecht, S. T1 - Conformationally pre-organized and pH-responsive flat dendrons: Synthesis and self-assembly at the liquid-solid interface N2 - Efficient Cu-catalyzed 1,3-dipolar cycloaddition reactions have been used to prepare two series of three regioisomers of G-1 and G-2 poly(triazole-pyridine) dendrons. The G-1 and G-2 dendrons consist of branched yet conformationally pre-organized 2,6-bis(phenyl/pyridyl-1,2,3-triazol-4-yl)pyridine (BPTP) monomeric and trimeric cores, respectively, carrying one focal and either two or four peripheral alkyl side chains. In the solid state, the conformation and supramolecular organization were studied by means of a single crystal X-ray structure analysis of one derivative. At the liquid-solid interface, the self-assembly behavior was investigated by scanning tunneling microscopy (STM) on graphite surfaces. Based on the observed supramolecular organization, it appears that the subtle balance between conformational preferences inherent in the dendritic backbone on the one side and the adsorption and packing of the alkyl side chains on the graphite substrate on the other side dictate the overall structure formation in 2D. KW - Dendrons KW - Scanning tunneling microscopy (STM) KW - Single crystal X-ray structure analysis PY - 2012 DO - https://doi.org/10.1039/c1nr11434d SN - 2040-3364 SN - 2040-3372 VL - 4 SP - 467 EP - 472 PB - RSC Publ. CY - Cambridge AN - OPUS4-25378 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -