TY - JOUR A1 - Solomun, Tihomir A1 - Mix, Renate A1 - Sturm, Heinz T1 - Immobilization of silanized DNA on glass: influence of the silane tether on the DNA hybridization N2 - Two trifunctional (trimethoxy and triethoxy) and one difunctional (methyldimethoxy) 3-mercaptopropyl-alkoxysilanes were covalently tethered to thiolated DNA oligonucleotides in solution. After deposition as microarrays onto glass, the immobilized DNA probes were tested for hybridization ability by a florescence-based method. The results demonstrate a large enhancement in the fluorescence signal when the functionality of the silane tether is reduced from three to two. An XPS analyses revealed that this is not due to a higher DNA surface density. FTIR spectra of the spin-coated silanes showed that the trifunctional silanes form branched and cyclic siloxane moieties, whereas the difunctional silane generates predominantly short straight siloxane chains. Therefore, the propensity of trifunctional silanes to form more complex networks leads to conformations of the bound DNA which are less favorable for the specific interaction with the complementary strand. The data implicate that further significant improvements in the DNA hybridization ability are possible by adroit choice of the silane system. KW - Silanized DNA KW - DNA immobilization KW - DNA hybridization KW - Fluorescence imaging KW - FTIRS KW - XPS PY - 2010 DO - https://doi.org/10.1021/am100263t SN - 1944-8244 SN - 0013-936X SN - 1944-8252 VL - 2 IS - 8 SP - 2171 EP - 2174 PB - ACS Publ. CY - Washington, DC, USA AN - OPUS4-22614 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Trappe, Volker A1 - Hickmann, Stefan A1 - Sturm, Heinz T1 - Bestimmung des Zwischenfaserbruchversagens in textilverstärktem Glasfaserkunststoff mittels der Röntgenrefrationstopografie N2 - Moderne Leichtbaustrukturen (Luftfahrt, Eisenbahn, Automotive) aus Faserverbundwerkstoffen (FVW) sind hohen mechanischen und klimatischen Beanspruchungen ausgesetzt. Aussagen über die Lebensdauer und Funktionssicherheit der FVW-Bauteile können eher aus Untersuchungen der mikromechanischen Eigenschaften gewonnen werden als aus der globalen Festigkeit. Die Röntgenrefraktionstopografie ist ein Verfahren zur zerstörungsfreien Bestimmung von inneren Oberflächen in Werkstoffen. Angewendet auf FVW lassen sich Aussagen über die Faserorientierungen, die Fertigungsqualität sowie über Faser-Matrix-Ablösungen und Matrixrisse infolge mechanischer Beanspruchung gewinnen. Nachfolgend wird ein neues Verfahren zur Bestimmung des Zwischenfaserbruchversagens am komplexen Laminat vorgestellt. Hierbei wird das Röntgenrefraktionsverfahren "online“ bei Zug-Belastung der Probe angewendet. KW - Zerstörungsfreie Prüfung KW - Röntgenstreuung KW - Faserverbundwerkstoffe KW - Mikrorissbildung KW - Glasfaserverstärkter Kunststoff PY - 2008 SN - 0025-5300 VL - 50 IS - 10 SP - 615 EP - 622 PB - Hanser CY - München AN - OPUS4-18282 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Heinz T1 - Messungen lokaler elektrischer Eigenschaften an keramischen Dielektrika T2 - 29. Kolloquium des Arbeitskreises für Elektronenmikroskopische Direktabbildung und Analyse von Oberflächen (EDO) der Deutschen Gesellschaft für Elektronenmikroskopie e.V. CY - Münster, Germany DA - 1996-10-10 PY - 1996 AN - OPUS4-6393 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Heinz T1 - Reducing bleaching in organic nanofibers by bi-layer polymer/oxide coating T2 - 10. International Conference on "Nanostructured Material" (NANO 2010) CY - Rome, Italy DA - 2010-09-13 PY - 2010 AN - OPUS4-21952 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Heinz T1 - Messungen der lokalen Leitfähigkeit und Oberflächenaufladung im Rasterkraftmikroskop T2 - Frühjahrstagung des Fachausschusses Polymerphysik der Deutschen Physikalischen Gesellschaft (DPG) CY - Marburg, Germany DA - 1996-03-18 PY - 1996 AN - OPUS4-6395 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Heinz T1 - Rasterkraftmikroskopie in der Faserverbundwerkstoffforschung T2 - Berliner Polymerentage CY - Berlin, Germany DA - 1993-05-06 PY - 1993 AN - OPUS4-6382 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Munz, Martin A1 - Sturm, Heinz A1 - Schulz, Eckhard T1 - Interphase Characterization via the Stiffness Contrast of a Scanning Force Microscope in Displacement Modulation Mode N2 - The physical properties as well as the thickness of the interphase between polymer and reinforcing phase are generally expected to show a strong influence on the macroscopic mechanical properties of composite materials. In this study the scanning force microscope (SFM) has been applied for detecting stiffness gradients near the interface between copper and epoxide. In displacement modulation mode the load exerted by the tip is modulated sinusoidally by vibrating the normal position of the cantilever or the sample. The corresponding amplitude of dynamic cantilever bending is related to local surface stiffness. Thus, using the SFM, the local mechanical properties of the surface under investigation can be probed. When scanning the tip across the reinforcement/polymer interface, the polymeric interphasial zone can be identified with the observed stiffness gradient. For a commercial epoxide based on diglycidyl ether of bisphenol A (DGEBA) cured with an amine-containing hardener, a stiffness gradient was detected that could be fitted by a Gaussian profile typical for diffusional processes. The width of the stiffness gradient was 280 nm. The observation is discussed in terms of interface-induced segregation processes between resin and hardener, as well as heat conduction mechanisms that can occur during the exothermic curing reaction. Both mechanisms are diffusional in nature and, via the local network structure, are expected to show some influence on the local stiffness of the cured epoxy. Copyright © 2000 John Wiley & Sons, Ltd. T2 - ECASIA 99 CY - Sevilla, Spain DA - 1999-10-04 KW - Scanning Force Microscopy KW - Surface properties KW - Nanomechanics KW - Interface/Interphase KW - Polymer-matrix composites (PMCs) KW - Adherends PY - 2000 DO - https://doi.org/10.1002/1096-9918(200008)30:1<410::AID-SIA846>3.0.CO;2-G SN - 0142-2421 SN - 1096-9918 VL - 30 IS - 1 SP - 410 EP - 414 PB - Wiley CY - Chichester AN - OPUS4-873 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Braun, Ulrike A1 - Sturm, Heinz A1 - Schartel, Bernhard T1 - Flame retardancy mechanisms of aluminium phosphinate in glass-fibre reinforced polyester T2 - Flame Retardants 2008 Conference CY - London, UK DA - 2008-02-12 PY - 2008 SN - 978-0-9556548-1-7 SP - 133 EP - 140 PB - Interscience Communications CY - London, UK AN - OPUS4-17785 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Heinz T1 - Modulated Lateral Force Microscopy (M-LFM): principles, experiments and unsolved problems T2 - Institut für Physik der Universität Basel CY - Basel, Switzerland DA - 2003-02-20 PY - 2003 AN - OPUS4-4097 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Heinz T1 - Kraft-Modulationstechniken am AFM zum Schreiben und Analysieren kleiner Strukturen T2 - BAM-Kolloquium CY - Berlin, Germany DA - 2000-11-09 PY - 2000 AN - OPUS4-6506 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Barthel, Anne-Kathrin A1 - Wachtendorf, Volker A1 - Sturm, Heinz A1 - Meyer-Plath, A. ED - Ziegahn, K.-F. T1 - Wirkung simulierter Sonnenstrahlung auf Kohlenstoffnanoröhren gefüllte Polymerkomposite N2 - Durch das Füllen von Polymeren mit Nanopartikeln oder Nanoröhren werden verbesserte Materialeigenschaften z.B. bezüglich mechanischer Stabilität, Witterungsbeständigkeit, elektrischer Leitfähigkeit und Flammschutz angestrebt. Mit dem vermehrten Einsatz derartiger Nanokomposite gewinnen aber auch Fragen des Umwelt- und Gesundheitsschutzes an Bedeutung. Es gilt zu klären, ob durch Herstellung, Benutzung und Witterungsbeanspruchung möglichweise nanoskalige Partikel freigesetzt werden können. Zu diesem Zweck wurden mit Kohlenstoffnanoröhren, Carbon Nanotubes (CNT), gefüllte Polymerkomposite spektral breitbandig wie auch quasimonochromatisch unter variierter klimatischer Beanspruchung bestrahlt. Die sich vor allem an der Oberfläche mit der Alterung abzeichnenden Veränderungen wurden mikroskopisch und spektroskopisch charakterisiert. T2 - 43. Jahrestagung der GUS 2014 CY - Stutensee-Blankenloch, Germany DA - 26.03.2014 KW - Nanokomposit KW - Nanopartikel KW - CNT KW - Bewitterung KW - Bestrahlung KW - Simulierte Sonnenstrahlung KW - Alterung PY - 2014 SN - 978-3-9816286-0-9 SP - 65 EP - 74 AN - OPUS4-31160 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bovtun, V. A1 - Sturm, Heinz A1 - Pashkov, V.M. ED - Baptista, J. T1 - Investigation of local electrical properties and topography of homo- and heterogeneous TiO2-containing ceramics by scanning force microscopy (SFM) T2 - 5th International Conference on Electronic Ceramics & Applications CY - Aveiro, Portugal DA - 1996-09-02 KW - Ceramics KW - Scanning force microscopy KW - SFM KW - Electrical properties KW - Heterogeneity PY - 1996 SN - 972-828317-2 VL - 2 SP - 117 EP - 120 PB - Fundação João Jacinto de Magalhães CY - Aveiro AN - OPUS4-6850 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Heinz T1 - Methoden der Rasterelektronen- und Rasterkraftmikroskopie zur Analyse von Faserverbundwerkstoffen T2 - 15. Nationales Symposium SAMPE Deutschland e.V. CY - Berlin, Germany DA - 2009-02-18 PY - 2009 AN - OPUS4-20750 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Heinz T1 - Nanotechnologie auf Kunststoff-Oberflächen T2 - Hannover-Messe CY - Hanover, Germany DA - 1999-04-19 PY - 1999 AN - OPUS4-6499 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Heinz T1 - Characterisierung des Faser/Polymer-Interface mittels messungen lokaler mikromechanischer Eigenschaften in der Rasterkraftmikroskopie T2 - Frühjahrstagung der DPG, FA: Polymerphysik CY - Münster, Germany DA - 1997-03-17 PY - 1997 AN - OPUS4-6414 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Heinz T1 - Messung elektrischer Eigenschaften in der Rasterkraftmikroskopie: Leitfähigkeitskontrast und Ladungskontrast T2 - 1. Jenaer Anwendersymposium Rastersondenmikroskopie CY - Jena, Germany DA - 1995-11-22 PY - 1995 AN - OPUS4-6390 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Munz, Martin A1 - Schulz, Eckhard A1 - Sturm, Heinz T1 - Use of scanning force microscopy studies with combined friction, stiffness and thermal diffusivity contrasts for microscopic characterization of automotive brake pads KW - Antimony sulphide KW - Polybutadiene KW - Phenolic resin KW - SFM/AFM KW - Friction KW - Thermal diffusivity PY - 2002 DO - https://doi.org/10.1002/sia.1171 SN - 0142-2421 SN - 1096-9918 VL - 33 IS - 2 SP - 100 EP - 107 PB - Wiley CY - Chichester AN - OPUS4-1293 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schönhals, Andreas A1 - Frunza, S. A1 - Frunza, L. A1 - Goering, Harald A1 - Sturm, Heinz T1 - On the dynamics of surface layer in octylcyanobiphenyl-aerosil systems N2 - A broadband dielectric study of the dispersions of silica spheres (Aerosil 380) in octylcyanobiphenyl (8CB) with densities between 0.083 and 10 g of silica per 1 cm3 of liquid crystal (LC) is reported. High values of silica densities were achieved for the first time to observe the behaviour of the LC monolayer on the surface of the silica particles. The relaxation characteristic of the bulk LC is noticed especially for the samples with low silica densities. Additionally, a slow relaxation was detected, even at temperatures for which the bulk LC is in the crystalline state. It was assigned to the surface layer of LC molecules. Remarkably, the temperature dependence of the relaxation rates for this slow process shows a behaviour typical for glass-forming liquids. PY - 2001 DO - https://doi.org/10.1209/epl/i2001-00591-8 SN - 0302-072X SN - 0295-5075 SN - 1286-4854 VL - 56 IS - 6 SP - 801 EP - 807 PB - EDP Science CY - Les-Ulis Cedexa, France AN - OPUS4-1572 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Heinz T1 - Von makroskopischen Fragestellungen und mikroskopischen Untersuchungsmethoden in der Tribologie T2 - Kolloquium "Synergie von Werkstoff- und Prozesstechnik" CY - Berlin, Germany DA - 2010-06-04 PY - 2010 AN - OPUS4-21617 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chung, Jae Un A1 - Munz, Martin A1 - Sturm, Heinz T1 - Stiffness variation in the interphase of amine-cured epoxy adjacent to copper microstructures N2 - In an effort to expand the understanding of the mechanical properties of the polymeric interphase on a metal surface, a composite consisting of epoxy and copper was prepared and analyzed. Scanning force microscopy-based force modulation microscopy (SFM-FMM) was employed along with dynamic mechanical analysis (DMA) and energy dispersive X-ray analysis (EDX). Diglycidyl ether of bisphenol A (DGEBA)-based epoxy resins were applied with amine curing agents. The samples were made taking advantage of electron beam lithography (EBL) in order to produce sharp edges of copper structures and a flat surface suitable for the SFM-FMM analysis, which was able to depict the stiffness within the interphase. It is considered significant information because the mechanical characteristic within the narrow interphase was revealed. Comparing with DMA and EDX, the stiffness information of SFM-FMM demonstrated a matching correlation and agreement in terms of preferential adsorption of the curing agent in the vicinity of the interface. The stiffness profiles of the two epoxy systems turned out to be different, and it shows the material dependence of the interphase characteristics. KW - Polymer-metal KW - Interphase KW - Stiffness KW - SFM/AFM KW - DMA KW - EDX KW - Epoxy KW - Copper PY - 2007 SN - 0142-2421 SN - 1096-9918 VL - 39 IS - 7 SP - 624 EP - 633 PB - Wiley CY - Chichester AN - OPUS4-14973 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Munz, Martin A1 - Sturm, Heinz T1 - The Normal Force Modulation as a method for Studying the Interphase of Fibre Reinforced Polymer T2 - 24th Intern. TopoMetrix-Workshop: Aktuelle Entwicklungen in der Nanotechnologie und Rastersondenmikroskopie, Humboldt-Universität CY - Berlin, Germany DA - 1998-03-12 PY - 1998 AN - OPUS4-6457 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Heinz T1 - Untersuchungen zur Materialzusammensetzung der Oberfläche eines Polymerblends: Eine vergleichende Studie zur Aussagefähigkeit mechanischer und elektrischer Zusatzkontraste im SFM T2 - Diskussionstagung: Raster-Sonden-Mikroskopien und Organische Materialien V CY - Münster, Germany DA - 1996-10-09 PY - 1996 AN - OPUS4-6391 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Heinz T1 - Modulated lateral force microscopy: an AFM tool for analysis and modification of polymer surfaces T2 - Viennano 2007, Tagung des österreichischen Tribologenverbands CY - Vienna, Austria DA - 2007-03-14 PY - 2007 AN - OPUS4-18130 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Heinz T1 - Dynamic Plowing Lithography T2 - International Workshop on Scanning Probe Microscopy in Nanotechnology CY - Wroclaw, Poland DA - 2001-07-09 PY - 2001 AN - OPUS4-6514 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Heinz T1 - SFM inside ESEM: A study of the electric properties of Polyaniline T2 - Polydays 2002 CY - Berlin, Germany DA - 2002-09-30 PY - 2002 AN - OPUS4-6538 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tavares, L. A1 - Kjelstrup-Hansen, J. A1 - Rubahn, H.-G. A1 - Sturm, Heinz T1 - Reduced bleaching in organic nanofibers by bilayer polymer/oxide coating N2 - Para-hexaphenylene (p-6P) molecules exhibit a characteristic photoinduced reaction (bleaching) resulting in a decrease in luminescence intensity upon UV light exposure, which could render the technological use of the nanofibers problematic. In order to investigate the photoinduced reaction in nanofibers, optical bleaching experiments have been performed by irradiating both pristine and coated nanofibers with UV light. Oxide coating materials (SiOx and Al2O3) were applied onto p-6P nanofibers. These treatments caused a reduction in the bleaching reaction but in addition, the nanofiber luminescence spectrum was significantly altered. It was observed that some polymer coatings [a statistical copolymer of tetrafluoroethylene and 2,2-bis-trifluoromethyl-4,5-difluoro-1,3-dioxole, P(TFE-PDD), and poly(methyl methacrylate), PMMA] do not interfere with the luminescence spectrum from the p-6P but are not effective in stopping the bleaching. Bilayer coatings with first a polymer material, which should work as a protection layer to avoid modifications of the p-6P luminescence spectrum, and second an oxide layer used as oxygen blocker were tested and it was found that a particular bilayer polymer/oxide combination results in a significant reduction in bleaching without affecting significantly the emission spectrum from the nanofibers. KW - Nanofibers KW - Photobleaching KW - Polymer coating KW - Oxide coating PY - 2010 DO - https://doi.org/10.1063/1.3427561 SN - 0021-8979 SN - 1089-7550 VL - 107 SP - 103521-1 - 103521-6 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-21574 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cappella, Brunero A1 - Sturm, Heinz A1 - Schulz, Eckhard T1 - Stiffness and adhesion characterization of nanolithographed poly(methyl methacrylate) by means of force-displacement curves N2 - Poly(methyl methacrylate) (PMMA) surfaces have been modified by dynamic plowing lithography. The resulting modified structures, presenting regions of different densities and stiffnesses, have been studied by force–displacement curves. The elasto-plastic response, the stiffness, and the adhesion of the modified samples have been characterized. Force–displacement curves are able to distinguish between unmodified PMMA and two different structures resulting from the lithography, i.e. compressed PMMA and low density PMMA. In particular, the low density regions are made up of cluster-like globular particles, whose elasto-plastic response and adhesion are measured and whose contribution to the total elasto-plastic response and to the adhesion has been studied in detail. KW - AFM KW - Lithography KW - Force-displacement curves KW - Stiffness KW - Adhesion KW - Elasto-plastic response PY - 2002 DO - https://doi.org/10.1163/156856102760136472 SN - 0169-4243 SN - 1568-5616 VL - 16 IS - 7 SP - 921 EP - 933 PB - VNU Science Press CY - Utrecht AN - OPUS4-1609 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maibohm, C. A1 - Brewer, J.R. A1 - Sturm, Heinz A1 - Balzer, F. A1 - Rubahn, H.-G. T1 - Bleaching and coating of organic nanofibers N2 - Based on an analysis of the diffusive heat flow equation, we determine limits on the localization of heating of soft materials and biological tissues by electromagnetically excited nanoparticles. For heating by rf magnetic fields or heating by typical continuous wave lasers, the local temperature rise adjacent to magnetic or metallic nanoparticles is negligible. However, heat dissipation for a large number of nanoparticles dispersed in a macroscopic region of a material or tissue produces a global temperature rise that is orders of magnitude larger than the temperature rise adjacent to a single nanoparticle. One approach for producing a significant local temperature rise on nanometer length scales is heating by high-power pulsed or modulated lasers with low duty cycle. KW - Nanofibers KW - Degradation KW - Bleaching KW - Luminescence KW - Silicon monoxide KW - Diffusion barrier KW - Security labels PY - 2006 DO - https://doi.org/10.1063/1.2335783 SN - 0021-8979 SN - 1089-7550 VL - 100 SP - 054304-1 - 054304-6 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-12761 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Heinz T1 - Imaging and simulation of mode shapes and harmonics of AFM cantilevers using Scanning Electron Microscopy T2 - 4th Multifrequency AFM Conference CY - Madrid, Spain DA - 2012-10-15 PY - 2012 AN - OPUS4-27342 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -