Study of Long-Range Tilt Orientation in Fatty Acid Monolayers by Dynamic Scanning Force Microscopy

F., L.; Gleiche, Michael; Fuchs, Harald

doi:10.1021/la9705569

Cited by 17 publications

(16 citation statements)

References 23 publications

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“…Those observations allow us to understand the contact stiffness during force modulation from a more microscopic level. During contact mode AFM imaging, deformation (δ) of the surface occurs under the tip, which propagates into the bulk. − In the case of tip−mica contact, such deformation may be due to the creation of defects, e.g. deformation of the lattice at high pressure or even breaking of some Si−O or Al−O bonds under extremely high loads. − The degree of local deformation varies during force modulation.…”

Section: Resultsmentioning

confidence: 99%

“…During contact mode AFM imaging, deformation (δ) of the surface occurs under the tip, which propagates into the bulk. − In the case of tip−mica contact, such deformation may be due to the creation of defects, e.g. deformation of the lattice at high pressure or even breaking of some Si−O or Al−O bonds under extremely high loads. − The degree of local deformation varies during force modulation. These motions may be excited at certain driving frequencies superpositioned with their resonances.…”

Section: Resultsmentioning

confidence: 99%

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Imaging Nanoscopic Elasticity of Thin Film Materials by Atomic Force Microscopy: Effects of Force Modulation Frequency and Amplitude

et al. 1999

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Octadecyltriethoxysilane (OTE) monolayers on mica are imaged using force modulation microscopy (FMM) and dynamic force modulation (DFM). Nanoscopic areas of mica are produced within OTE layers and serve as an internal standard for contact stiffness measurements. The contact stiffness is systematically studied as a function of imaging medium and force modulation amplitude and frequency. Measurements taken in liquid media are found to reflect more accurately the viscoelastic properties of the sample, while imaging in air is perturbed by the capillary neck at contact. Increasing modulation amplitude increases the overall signal in FMM. However, extremely large amplitudes diminish the contrast difference between OTE and mica because the sensing depth is much higher than the monolayer. The measured contact stiffness is found to depend sensitively upon the modulation frequency because of the presence of several resonances within 10−50 kHz, which cause the image contrast to vary or to flip. Collective motion of the molecules under contact is most likely responsible for these resonances. The observed amplitude and frequency dependence also allows active control of FMM image contrast.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Imaging Nanoscopic Elasticity of Thin Film Materials by Atomic Force Microscopy: Effects of Force Modulation Frequency and Amplitude

et al. 1999

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“…Further experimental and theoretical efforts are required to find out the optimum conditions for ''tailor-made'' tips of other materials adapted to the particular problem to be solved. 26 …”

Section: Discussionmentioning

confidence: 99%

Nanostructuring of tips for scanning probe microscopy by ion sputtering: Control of the apex ratio and the tip radius

Hoffrogge

Kopf

Reichelt

2001

Journal of Applied Physics

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Single crystal diamond tips for scanning probe microscopy Rev. Sci. Instrum. 81, 013703 (2010); 10.1063/1.3280182 Scanning probe microscopy investigation of nanostructured surfaces induced by swift heavy ionsIon etching under well-defined conditions represents a very powerful tool to fabricate tips in a controlled and reproducible manner for Scanning Probe Microscopy which possess clean, relatively smooth, and oxide-free surfaces. The possibilities and limitations of ion etching are demonstrated thoroughly for tungsten, which is of particular interest for scanning tunneling microscopy. Iterative computer simulations and experimental studies are provided. The simulation of the etching process at the atomic level is based on the Monte Carlo program ͑Transport of Ions in Matter͒, which provides reliable values for the key input parameters such as the sputtering yield Y (,E ion ) and the mean ion range in the material for ion energies between 1 and 6 keV. The simulation program starts with a large tip radius as a crude form and asymptotically approaches a ''final form'' of a very sharp tip in the course of ion etching. Our experimental results with argon ions in the energy range up to 6 keV and crude electrochemically etched polycrystalline tungsten wire agreed very reasonably with the simulated results. For example, the minimum tip radius obtained experimentally amounts to approximately 5 nm. This value corresponds closely to the ion range, which obviously sets a limit to the smallest achievable tip radius by the effect of transmission sputtering. By variation of the angle between the ion beam and the macroscopic tip, the tip angle can be controlled in the range between 12°and 35°.

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“…The images obtained from tapping and non-contact mode are basically identical, indicating that destruction of the sample can be neglected. In order to support our findings on material properties contrast produced by protein insertion, we used FMM as supplied by Digital Instruments using the same LB film (Chi et al, 1998) (Fig. 9).…”

Section: Materials Properties Contrastmentioning

confidence: 94%

Formation of Three-Dimensional Protein-Lipid Aggregates in Monolayer Films Induced by Surfactant Protein B

Krol

Ross

Sieber

et al. 2000

Biophysical Journal

124

114

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This study focuses on the structural organization of surfactant protein B (SP-B) containing lipid monolayers. The artificial system is composed of the saturated phospholipids dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylglycerol (DPPG) in a molar ratio of 4:1 with 0.2 mol% SP-B. The different "squeeze-out" structures of SP-B were visualized by scanning probe microscopy and compared with structures formed by SP-C. Particularly, the morphology and material properties of mixed monolayers containing 0.2 mol% SP-B in a wide pressure range of 10 to 54 mN/m were investigated revealing that filamentous domain boundaries occur at intermediate surface pressure (15-30 mN/m), while disc-like protrusions prevail at elevated pressure (50-54 mN/m). In contrast, SP-C containing lipid monolayers exhibit large flat protrusions composed of stacked bilayers in the plateau region (app. 52 mN/m) of the pressure-area isotherm. By using different scanning probe techniques (lateral force microscopy, force modulation, phase imaging) it was shown that SP-B is dissolved in the liquid expanded rather than in the liquid condensed phase of the monolayer. Although artificial, the investigation of this system contributes to further understanding of the function of lung surfactant in the alveolus.

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Study of Long-Range Tilt Orientation in Fatty Acid Monolayers by Dynamic Scanning Force Microscopy

Cited by 17 publications

References 23 publications

Imaging Nanoscopic Elasticity of Thin Film Materials by Atomic Force Microscopy: Effects of Force Modulation Frequency and Amplitude

Imaging Nanoscopic Elasticity of Thin Film Materials by Atomic Force Microscopy: Effects of Force Modulation Frequency and Amplitude

Nanostructuring of tips for scanning probe microscopy by ion sputtering: Control of the apex ratio and the tip radius

Formation of Three-Dimensional Protein-Lipid Aggregates in Monolayer Films Induced by Surfactant Protein B

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