The Experts below are selected from a list of 66168 Experts worldwide ranked by ideXlab platform
A. M. Baró - One of the best experts on this subject based on the ideXlab platform.
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Scanning Force Microscopy jumping and tapping modes in liquids
Applied Physics Letters, 2002Co-Authors: Fernando Moreno-herrero, P. J. De Pablo, R. Fernández-sánchez, Jaime Colchero, Julio Gómez-herrero, A. M. BaróAbstract:In this work theoretical considerations of the performance of Scanning Force Microscopy jumping mode and tapping mode in liquids are discussed. A priori, jumping mode should improve in a liquid environment compared to in air while the situation for tapping mode should become worse. In order to confirm this we present jumping and tapping mode images of DNA molecules absorbed on a mica substrate immersed in water. The experiments demonstrate that jumping mode is a suitable Scanning Force Microscopy method by which to image soft samples in liquid and that it has similar or even better performance than those exhibited by tapping, but without the complex experimental requirements of this mode.
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Macroscopic water deposits on polycrystalline gold measured by Scanning Force Microscopy.
Ultramicroscopy, 2001Co-Authors: A Gil, Jaime Colchero, Julio Gómez-herrero, A. M. BaróAbstract:Data of water adsorption on polycrystalline gold show the formation of a multilayer film of several nanometers with the increase of relative humidity. We have measured this adsorption process by Scanning Force Microscopy in both dynamic and jumping modes. We find interesting differences in the adsorption of water on the terraces and at grain boundaries. Measurements of adhesion Force are also reported.
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Tip-sample interaction in tapping-mode Scanning Force Microscopy
Physical Review B, 2000Co-Authors: P. J. De Pablo, Jaime Colchero, Julio Gómez-herrero, M. Luna, A. M. BaróAbstract:Tip-sample interaction in intermittent contact Scanning Force Microscopy, also called tapping mode, is experimentally studied to determine under which conditions tip-sample contact is established. Force vs distance curves are made while the cantilever is oscillating at its resonance frequency. Cantilevers with different Force constants driven at different oscillation amplitudes have been used. In addition, samples with different hardness, such as silicon oxide, glass, and highly orientated pyrolytic graphite were taken as sample surface. From the analysis of the data we conclude that by choosing appropriate operating conditions, tip-sample contact can be avoided. This operating regime is of general interest in Scanning Force Microscopy, since it allows imaging of even the softest samples.
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adsorption of water on solid surfaces studied by Scanning Force Microscopy
Langmuir, 2000Co-Authors: A Gil, M. Luna, J Colchero, And J Gomezherrero, A. M. BaróAbstract:Tip−sample interaction of an oscillating tip near a surface is determined. The experimental results show that the presence of the surface can be detected without mechanically touching the surface. By adjusting the appropriate operating conditions of a Scanning Force microscope setup, tip−sample contact can be avoided during imaging at atmospheric pressure. This allows study of even the softest samples. In the present work, we demonstrate that molecularly thin water films can be imaged with nanometer resolution on different substrates such as mica, gold, and highly oriented pyrolitic graphite. Correspondingly, Scanning Force Microscopy can be used to investigate wetting properties of liquids with very high spatial resolution.
Martin Möller - One of the best experts on this subject based on the ideXlab platform.
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Real‐Time Scanning Force Microscopy of Macromolecular Conformational Transitions
Macromolecular Rapid Communications, 2004Co-Authors: Marat O. Gallyamov, Sergei S. Sheiko, Bernd Tartsch, Alexei R. Khokhlov, Hans G. Börner, Krzysztof Matyjaszewski, Martin MöllerAbstract:Comb-like macromolecules were adsorbed on mica and imaged by Scanning Force Microscopy in real time as they underwent a transition from an extended worm-like conformation to globuli and vice versa. The conformational transition was effected by coadsorption of ethanol and water molecules. Coadsorption of the small molecules allowed manipulation of the adherence and spreading of the macromolecules, thus effecting the reptation like stretching and collapse of the single molecules.
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Shape and Quality Control of Modified Scanning Force Microscopy Tips
Ultramicroscopy, 1998Co-Authors: Joachim P. Spatz, Sergei S. Sheiko, Martin MöllerAbstract:Abstract A stepped (305) surface of a SrTiO 3 crystal was used to characterize the shape of gold-modified Scanning Force Microscopy tips. The tip radius increased from 8 nm to more than 30 nm with increasing the degree of the Au coverage from 0 to 40 nm. Contamination and subsequent cleaning is demonstrated.
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Tapping Scanning Force Microscopy in air - theory and experiment
Langmuir, 1997Co-Authors: Joachim P. Spatz, Sergei S. Sheiko, Martin Möller, Roland G. Winkler, Peter Reineker, Othmar MartiAbstract:Ultrathin layers of micelles of a diblock copolymer with a polystyrene corona and a poly(2-vinylpyridine) core have been studied by tapping Scanning Force Microscopy in air, probing the surface with varying Forces depending on the setpoint of the probe and the tapping frequency. The compliance of the core of the micelles was varied by neutralization of the pyridine groups with HAuCl 4 and incorporation of small particles. The apparent deformation of the globular micelles was compared with a simple model describing the probe as a Forced oscillator which changes its effective spring constant depending on the direct contact with the surface. Consistent with the experiment, the model shows that the deformation and the shift in phase are minimized by tapping on the low-frequency side of the noncontact cantilever resonance.
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Calibration and evaluation of Scanning-Force-Microscopy probes
Physical review. B Condensed matter, 1993Co-Authors: Sergei S. Sheiko, Martin Möller, E.m.c.m. Reuvekamp, H.w. ZandbergenAbstract:It is demonstrated that a stepped (305) surface of a SrTiO3 crystal can be used routinely to evaluate the probing profile of Scanning-Force-Microscopy probes. This provides a means to select optimal surface probes, and to evaluate possible image distortions within the range of the atomic and nanometer scale. The scope and limitations of the resolution of structural defects are discussed as a criterion for a true atomic resolution.
Sergei S. Sheiko - One of the best experts on this subject based on the ideXlab platform.
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Real‐Time Scanning Force Microscopy of Macromolecular Conformational Transitions
Macromolecular Rapid Communications, 2004Co-Authors: Marat O. Gallyamov, Sergei S. Sheiko, Bernd Tartsch, Alexei R. Khokhlov, Hans G. Börner, Krzysztof Matyjaszewski, Martin MöllerAbstract:Comb-like macromolecules were adsorbed on mica and imaged by Scanning Force Microscopy in real time as they underwent a transition from an extended worm-like conformation to globuli and vice versa. The conformational transition was effected by coadsorption of ethanol and water molecules. Coadsorption of the small molecules allowed manipulation of the adherence and spreading of the macromolecules, thus effecting the reptation like stretching and collapse of the single molecules.
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Shape and Quality Control of Modified Scanning Force Microscopy Tips
Ultramicroscopy, 1998Co-Authors: Joachim P. Spatz, Sergei S. Sheiko, Martin MöllerAbstract:Abstract A stepped (305) surface of a SrTiO 3 crystal was used to characterize the shape of gold-modified Scanning Force Microscopy tips. The tip radius increased from 8 nm to more than 30 nm with increasing the degree of the Au coverage from 0 to 40 nm. Contamination and subsequent cleaning is demonstrated.
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Tapping Scanning Force Microscopy in air - theory and experiment
Langmuir, 1997Co-Authors: Joachim P. Spatz, Sergei S. Sheiko, Martin Möller, Roland G. Winkler, Peter Reineker, Othmar MartiAbstract:Ultrathin layers of micelles of a diblock copolymer with a polystyrene corona and a poly(2-vinylpyridine) core have been studied by tapping Scanning Force Microscopy in air, probing the surface with varying Forces depending on the setpoint of the probe and the tapping frequency. The compliance of the core of the micelles was varied by neutralization of the pyridine groups with HAuCl 4 and incorporation of small particles. The apparent deformation of the globular micelles was compared with a simple model describing the probe as a Forced oscillator which changes its effective spring constant depending on the direct contact with the surface. Consistent with the experiment, the model shows that the deformation and the shift in phase are minimized by tapping on the low-frequency side of the noncontact cantilever resonance.
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Calibration and evaluation of Scanning-Force-Microscopy probes
Physical review. B Condensed matter, 1993Co-Authors: Sergei S. Sheiko, Martin Möller, E.m.c.m. Reuvekamp, H.w. ZandbergenAbstract:It is demonstrated that a stepped (305) surface of a SrTiO3 crystal can be used routinely to evaluate the probing profile of Scanning-Force-Microscopy probes. This provides a means to select optimal surface probes, and to evaluate possible image distortions within the range of the atomic and nanometer scale. The scope and limitations of the resolution of structural defects are discussed as a criterion for a true atomic resolution.
A Gil - One of the best experts on this subject based on the ideXlab platform.
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Macroscopic water deposits on polycrystalline gold measured by Scanning Force Microscopy.
Ultramicroscopy, 2001Co-Authors: A Gil, Jaime Colchero, Julio Gómez-herrero, A. M. BaróAbstract:Data of water adsorption on polycrystalline gold show the formation of a multilayer film of several nanometers with the increase of relative humidity. We have measured this adsorption process by Scanning Force Microscopy in both dynamic and jumping modes. We find interesting differences in the adsorption of water on the terraces and at grain boundaries. Measurements of adhesion Force are also reported.
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adsorption of water on solid surfaces studied by Scanning Force Microscopy
Langmuir, 2000Co-Authors: A Gil, M. Luna, J Colchero, And J Gomezherrero, A. M. BaróAbstract:Tip−sample interaction of an oscillating tip near a surface is determined. The experimental results show that the presence of the surface can be detected without mechanically touching the surface. By adjusting the appropriate operating conditions of a Scanning Force microscope setup, tip−sample contact can be avoided during imaging at atmospheric pressure. This allows study of even the softest samples. In the present work, we demonstrate that molecularly thin water films can be imaged with nanometer resolution on different substrates such as mica, gold, and highly oriented pyrolitic graphite. Correspondingly, Scanning Force Microscopy can be used to investigate wetting properties of liquids with very high spatial resolution.
Othmar Marti - One of the best experts on this subject based on the ideXlab platform.
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Tapping Scanning Force Microscopy in air - theory and experiment
Langmuir, 1997Co-Authors: Joachim P. Spatz, Sergei S. Sheiko, Martin Möller, Roland G. Winkler, Peter Reineker, Othmar MartiAbstract:Ultrathin layers of micelles of a diblock copolymer with a polystyrene corona and a poly(2-vinylpyridine) core have been studied by tapping Scanning Force Microscopy in air, probing the surface with varying Forces depending on the setpoint of the probe and the tapping frequency. The compliance of the core of the micelles was varied by neutralization of the pyridine groups with HAuCl 4 and incorporation of small particles. The apparent deformation of the globular micelles was compared with a simple model describing the probe as a Forced oscillator which changes its effective spring constant depending on the direct contact with the surface. Consistent with the experiment, the model shows that the deformation and the shift in phase are minimized by tapping on the low-frequency side of the noncontact cantilever resonance.
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Scanning Force Microscopy of diatom shells
Ultramicroscopy, 1992Co-Authors: Achim Linder, Jaime Colchero, Hans-jürgen Apell, Othmar Marti, J. MlynekAbstract:We have imaged surfaces of several diatom species by Scanning Force Microscopy with image areas of some squared micrometers. The algae cells were collected from a mud sample out of a small pond, rinsed briefly with ethanol to clean and immobilize them and deposited on a glass slide. The ease of obtaining images with a resolution of several ten nanometers makes the Scanning Force microscope competitive with Scanning electron Microscopy at medium magnification.
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Na,K-ATPase in crystalline form investigated by Scanning Force Microscopy
Ultramicroscopy, 1992Co-Authors: Hans-jiirgen Apell, Jaime Colchero, Achim Linder, Othmar Marti, Jiirgen MlynekAbstract:Na,K-ATPase has been isolated in purified membrane fragments from kidney tissue and crystallized by phospholipase treatment to obtain two-dimensional, membrane-bound protein crystals. Scanning Force Microscopy has been used to identify and analyze the topography of the membrane fragments. Specific patterns in accordance with electron microscopic images have been found. In biological material under physiological conditions the Scanning Force is a crucial parameter for the resulting image at high resolution.
