The Experts below are selected from a list of 16704 Experts worldwide ranked by ideXlab platform
Christopher Barnerkowollik - One of the best experts on this subject based on the ideXlab platform.
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photo induced click chemistry for dna Surface structuring by direct laser writing
2017Co-Authors: Antonina Kerbs, Patrick Mueller, Michael Kaupp, Charlotte M. Niemeyer, Ishtiaq Ahmed, Alexander S Quick, Christopher Barnerkowollik, Martin Wegener, Ljiljana FrukAbstract:Oligonucleotides containing photo-caged dienes were prepared and shown to react quantitatively in a light-induced Diels-Alder cycloaddition with functional maleimides in aqueous solution within minutes. Due to its high yield and fast rate, the reaction was exploited for DNA Surface Patterning with sub-micrometer resolution employing direct laser writing (DLW). Functional DNA arrays were written by direct laser writing (DLW) in variable patterns, which were further encoded with fluorophores and proteins through DNA directed immobilization. This mild and efficient light-driven platform technology holds promise for the fabrication of complex bioarrays with sub-micron resolution.
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polymer Surface Patterning via diels alder trapping of photo generated thioaldehydes
2013Co-Authors: Mathias Glassner, Alexander Welle, Klaus Kim Oehlenschlaeger, Michael Bruns, Christopher BarnerkowollikAbstract:An efficient method for polymer Surface Patterning via Diels–Alder trapping of photo-generated thioaldehydes is presented. It is demonstrated that thioaldehyde end-groups generated by photolysis of phenacyl sulfides can be quantitatively trapped with various dienes. Poly(ethylene glycol) is immobilized on a Surface in a spatially controlled fashion via irradiation through a shadow mask.
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bio molecular Surface Patterning by phototriggered oxime ligation
2012Co-Authors: Thomas Pauloehrl, Michael Bruns, Guillaume Delaittre, Maria Meisler, Hans G Borner, Martin Bastmeyer, Christopher BarnerkowollikAbstract:Making light work of ligation: A novel method utilizes light for oxime ligation chemistry. A quantitative, low-energy photodeprotection generates aldehyde, which subsequently reacts with aminooxy moieties. The spatial control allows Patterning on Surfaces with a fluoro marker and GRGSGR peptide, and can be imaged by time-of-flight secondary-ion mass spectrometry.
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bio molecular Surface Patterning by phototriggered oxime ligation
2012Co-Authors: Thomas Pauloehrl, Michael Bruns, Guillaume Delaittre, Maria Meisler, Hans G Borner, Martin Bastmeyer, Christopher BarnerkowollikAbstract:Making light work of ligation: A novel method utilizes light for oxime ligation chemistry. A quantitative, low-energy photodeprotection generates aldehyde, which subsequently reacts with aminooxy moieties. The spatial control allows Patterning on Surfaces (see scheme) with a fluoro marker and GRGSGR peptide, and can be imaged by time-of-flight secondary-ion mass spectrometry. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Frank Mucklich - One of the best experts on this subject based on the ideXlab platform.
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multi scale Surface Patterning to tune friction under mixed lubricated conditions
2019Co-Authors: Andreas Rosenkranz, Philipp G Grutzmacher, Kevin Murzyn, Cedric Mathieu, Frank MucklichAbstract:It is well accepted that the tribological performance of Surfaces can be directly correlated with their energy efficiency and lifetime. Consequently, Surface Patterning has gained great attention to manipulate friction and wear under dry and lubricated conditions in the last 2 decades. Inspired by multi-scale Surfaces found in nature, direct laser interference Patterning (finer cross-pattern) and hot micro-coining (coarser hemispherical patterns) were used to create multi-scale patterns on stainless steel substrates. Using a ball-on-disk set-up, the running-in behavior and the maximum oil film lifetime were characterized for all single- and multi-scale patterns under mixed lubrication. Compared to the polished reference, all patterned Surfaces helped to prolong the oil film lifetime. Synergetic effects induced by multi-scale patterns were observed leading to the best performance of the sample combining deep micro-coined patterns (intermediate area density) with the additional laser pattern. As a result of the additional hydrodynamic pressure generated by the finer laser pattern and the oil reservoir effect as well as the entrapment of wear particles induced by the coarser micro-coined pattern, the oil film lifetime was extended by a factor of 200 (200 times).
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A parametric study of laser interference Surface Patterning of dental zirconia: Effects of laser parameters on topography and Surface quality
2017Co-Authors: Erica Roitero, Federico Lasserre, Marc Anglada, Frank Mucklich, Emilio Jiménez-piquéAbstract:Objective The aim of this work is to generate micrometric linear patterns with different topography on dental grade zirconia by means of UV laser interference and to assess the quality of the produced Surface, both in term of the geometry produced and of the Surface damage induced in the material. Methods The third harmonic of a Q-switched Nd:YAG laser (355 nm, pulse duration of 10 ns and repetition rate of 1 Hz) was employed to pattern the Surface of 3Y-TZP with micrometric-spaced lines. The resulting topography was characterized with White Light Interferometry and Scanning electron microscopy: pattern depth (H), amplitude roughness parameters (Sa, filtered-Sa), Fourier spatial analysis and collateral damages were related to laser fluence and number of pulses employed. Results With our experimental setup, line-Patterning of zirconia Surfaces can be achieved with periodicities comprised within 5 and 15 μm. Tuning laser parameters allows varying independently pattern depth, overall roughness and Surface finish. Increasing both fluence and number of pulses allows producing deeper patterns (maximum achievable depth of 1 μm). However, increasing the number of pulses has a detrimental effect on the quality of the produced lines. Surface damage (intergranular cracking, open porosity and nano-droplets formation) can be generated, depending on laser parameters. Significance This work provides a parametric analysis of Surface Patterning by laser interference on 3Y-TZP. Best conditions in terms of quality of the produced pattern and minimum material damage are obtained for low number of pulses with high laser fluence. With the employed method we can produce zirconia materials with controlled topography that are expected to enhance biological response and mechanical performance of dental components.
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increasing lubricant film lifetime by grooving periodical patterns using laser interference metallurgy
2008Co-Authors: M Duarte, Andres Fabian Lasagni, Romain Giovanelli, J Narciso, E Louis, Frank MucklichAbstract:A new laser Surface Patterning technique called Laser Interference Metallurgy is used to structure metallic samples, attempting to increase the lubricant film lifetime. Lifetime tests were carried out for several pattern geometries and two laser intensities. In some cases, lifetime improvements were remarkable, up to around 1500 %.
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laser interference metallurgy periodic Surface Patterning and formation of intermetallics
2005Co-Authors: Frank Mucklich, A Lasagni, Claus DanielAbstract:Abstract A new kind of Surface modification, called ‘laser interference metallurgy’ is reported. It allows the creation of periodic pattern of features with a well defined long-range order on metallic Surfaces in the scale of typical microstructures (i.e. from the sub micrometer level up to micrometers). By means of interfering laser beams with sufficient high pulse power a direct structuring in the micro scale with well known metallurgical effects such as melting, recrystallization, quenching, recovery, defect or phase formation can be exploited. Thus, long range ordered arrays of such pattern of phases, defects, grain sizes, textures or stresses could be created. This should open up a remarkable potential to tailor mechanical and other properties by microstructural Surface functionalization. The topographic structuring of metallic multilayers as well as the lateral formation of patterns of B2 intermetallic compounds (NiAl and RuAl) and L1 2 intermetallic compound (Ni 3 Al) are reported as examples.
Juergen Reif - One of the best experts on this subject based on the ideXlab platform.
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self organized regular Surface Patterning by pulsed laser ablation
2009Co-Authors: Juergen Reif, Florenta Costache, Olga Varlamova, Guobin Jia, Markus RatzkeAbstract:The impact of intense ultra short laser pulses on solid Surface - as in laser ablation - results in a transient perturbation of the material to a state far from equilibrium. Due to ultrafast relaxation of the transient disorder in a few picoseconds, self-organized Surface patterns occur, with a typical feature size at the order of 100 nm or less, similar as observed in ion sputtering and explained by non-linear dynamics models. The feature size of these structures is determined by the deposited energy dose, their shape and orientation crucially depends on the state of polarization of the incident light. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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Surface Patterning on insulators upon femtosecond laser ablation
2003Co-Authors: Florenta Costache, M Henyk, Juergen ReifAbstract:Abstract The crater morphology upon femtosecond laser ablation from BaF2 and CaF2, exhibits several periodic structures of characteristics that cannot be explained by interference phenomena. More likely, the ripple pattern presents features of self-organization from a chaotic state. The ablation under the applied conditions is due to Coulomb explosion of the Surface, which indicates that local thermal effects should play a minor role in the ripple formation. In this paper, we present morphological structures that point toward instabilities and self-organization.
Ya Cheng - One of the best experts on this subject based on the ideXlab platform.
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metal Surface structuring with spatiotemporally focused femtosecond laser pulses
2018Co-Authors: Zhiwei Fang, Yang Liao, Ya ChengAbstract:Femtosecond laser micromachining provides high precision and less thermal diffusion in Surface structuring as a result of the ultrashort duration and ultrahigh peak intensity of the femtosecond laser pulses. To increase the throughput of Surface Patterning, the focal spot size can be expanded with loose focusing, which, however, could lead to nonlinear self-focusing of the pulses when the pulses propagate in air. We solve the problem by use of spatiotemporally focused femtosecond laser pulses for ablation of metal Surfaces, which gives rise to improved Surface quality as compared with that obtained with the conventional focusing scheme.
Michael Bruns - One of the best experts on this subject based on the ideXlab platform.
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polymer Surface Patterning via diels alder trapping of photo generated thioaldehydes
2013Co-Authors: Mathias Glassner, Alexander Welle, Klaus Kim Oehlenschlaeger, Michael Bruns, Christopher BarnerkowollikAbstract:An efficient method for polymer Surface Patterning via Diels–Alder trapping of photo-generated thioaldehydes is presented. It is demonstrated that thioaldehyde end-groups generated by photolysis of phenacyl sulfides can be quantitatively trapped with various dienes. Poly(ethylene glycol) is immobilized on a Surface in a spatially controlled fashion via irradiation through a shadow mask.
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Polymer Surface Patterning via Diels-Alder trapping of photo-generated thioaldehydes
2013Co-Authors: Mathias Glassner, Alexander Welle, Klaus Kim Oehlenschlaeger, Michael Bruns, Christopher Barner-kowollikAbstract:An efficient method for polymer Surface Patterning via Diels-Alder trapping of photo-generated thioaldehydes is presented. It is demonstrated that thioaldehyde end-groups generated by photolysis of phenacyl sulfides can be quantitatively trapped with various dienes. Poly(ethylene glycol) is immobilized on a Surface in a spatially controlled fashion via irradiation through a shadow mask. © 2013 The Royal Society of Chemistry.
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bio molecular Surface Patterning by phototriggered oxime ligation
2012Co-Authors: Thomas Pauloehrl, Michael Bruns, Guillaume Delaittre, Maria Meisler, Hans G Borner, Martin Bastmeyer, Christopher BarnerkowollikAbstract:Making light work of ligation: A novel method utilizes light for oxime ligation chemistry. A quantitative, low-energy photodeprotection generates aldehyde, which subsequently reacts with aminooxy moieties. The spatial control allows Patterning on Surfaces with a fluoro marker and GRGSGR peptide, and can be imaged by time-of-flight secondary-ion mass spectrometry.
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bio molecular Surface Patterning by phototriggered oxime ligation
2012Co-Authors: Thomas Pauloehrl, Michael Bruns, Guillaume Delaittre, Maria Meisler, Hans G Borner, Martin Bastmeyer, Christopher BarnerkowollikAbstract:Making light work of ligation: A novel method utilizes light for oxime ligation chemistry. A quantitative, low-energy photodeprotection generates aldehyde, which subsequently reacts with aminooxy moieties. The spatial control allows Patterning on Surfaces (see scheme) with a fluoro marker and GRGSGR peptide, and can be imaged by time-of-flight secondary-ion mass spectrometry. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
