Scanning probe microscopic methods

There is a plethora of analytical techniques available to assess the acid-base properties of materials. They range from wettability and chromatographic measurements to spectroscopic approaches and more sophisticated scanning probe microscopic methods [12,13,15-19,59-61]. For the purpose of this contribution, the focus will be on contact angle measurements, inverse gas chromatography, x-ray photoelectron spectroscopy, and atomic force microscopy. 

In adhesion science and technology, the manifestations of acid-base interactions have been observed at both macroscopic and microscopic scales (wetting, adhesion, metallization, etc.). The development of scanning probe microscopic methods (scaiming tunneling microscopy (STM) and atomic force microscopy (AFM)) over the past decade has led to the possibility of measuring adhesion forces on the molecular scale in addition to imaging surfaces in atomic resolution. 

Scanning probe microscopic methods use a probe to obtain information on the surface... 

It is also common for pol3rmeric compoimds to form surface regions with compositions different from the bulk material, by selective diffusion of components. This process is termed blooming when the surface component is solid, and bleeding if it is liquid. Sulfur and fatty acid blooms can inhibit adhesion in rubber laminates (3). Laser desorption mass spectroscopy has been employed to identify surface species on vulcanized rubber (4). X-ray scattering methods for the study of polymer surfaces and interfaces have been reviewed (5). Other surface analysis techniques commonly used with polymers include attenuated total reflectance (6-8), electron microprobe (9), Auger electron spectroscopy (10), x-ray photoelectron spectroscopy (11), and scanning probe microscopic methods (12). Overviews on polymer surface analysis have been published (13,14). 

In our days the SECM is recognized as the member of numerous scanning probe microscopic techniques. Similarly to the other scanning probe microscopic methods, it employs a microsized measuring probe, three-dimensional positioning devices, computerized data collection, and evaluation. Special feature is, however, that in SECM electrochemical microprobes are used. 

No direct method exists by which monolayer film structures on water can be studied. Therefore, the LB method has been used to study molecular structures in past decades. The most useful method for investigating the detailed LB-deposited film structure is the well-known electron diffraction technique (or the scanning probe microscope [Birdi, 2002a]). The molecular arrangements of deposited mono-and multilayer films of fatty acids and their salts, using this technique, have been reported. The analyses showed that the molecules were almost perpendicular to the solid surface in the first monolayer. It was also reported that Ba-stearate molecules have a more precise normal alignment compared to stearic-acid monolayers. In some investigations, the thermal stability of these films has been found to be remarkably stable up to 90°C. 

The promise of hottom-up nanotechnology has always depended on solving the problem of having a way to move individual atoms and molecules into desired positions. The best method yet developed to solve this problem is the family of scanning probe microscopes, which are now being used to produce a host of nanosize devices, some of which are discussed in the next section. DNA molecules may also become a powerful tool in the manipulation of atoms and molecules, although their potential has yet to be fully developed. 

Characterization of surfaces and thin films has been revolutionized by the invention of scanning probe microscopes, i,e, scanning force microscopy, scanning tunnelling microscopy, and scanning near field optical microscopy [262-264], These methods not only allow imaging of molecular and supramolecular details, but can also be employed to probe and to manipulate chemical properties on a nanoscopic or molecular scale, e,g., mechanical SFM [265], chemical SFM [266], electrochemical STM [267,268],... 

Raman scattering spectroscopy integrated in a scanning probe microscope is effective and nondestructive method for analysis of the structural state, size and depth distribution of the silicon nanoinclusions in dielectric matrices. Average diameter of the nc-Si and compressive stresses obtained from Raman measurements are in good agreement with the TEM data and theoretical stress estimation. 

Both the transmission electron microscope and the scanning probe microscope (particularly the atomic force microscope) are the highest-resolution-imaging devices available for biochemical research. While knowledge of the instruments is important, the selection of appropriate methods of specimen preparation and the correct execution of those methods are critical for accurate ultrastructural data. In fact, use of more than one method can be quite desirable, especially if alternative methods of data corroboration are not available. 

P. G. Ganesan, X. Wang, and O. Nalamasu, Method for sensing the self-assembly of polyelectrolyte monolayers using scanning probe microscope cantilever. Applied Physics Letters 89 p. 213107-213113 (2006). 

Abstract. Arrangement of DNA based structures on mica and modified Si surfaces is investigated by methods of scanning probe microscope (SPM) and spectroscopic ellipso-metry (SE). DNA strands are deposited from a colloidal solution on the surfaces at room temperature. The surfaces were additionally modified with Ag nanoparticles by special technology. The surface structures are visualized by SPM. The effect of the multicomponent structures on the optical response of complex hybrid structures is studied. The optical response of the hybrid samples is related to the contributions of DNA and Ag nanoparticles on the Si surfaces. Formation of combined structures based on Ag nanoparticles and DNA strands is discussed. 

Recently, the structure of the solid/liquid interface has been studied with a wide range of in-situ structural techniques. In particular, scanned probe microscopes [1-5] and synchrotron-based methods [6-9] have yielded a wealth of structural information. The ultimate goal of this work is an understanding of the structure and reactivity of the electrode surface at the atomic level. One of the most extensively studied processes is metal underpotential deposition (UPD) [10], which involves the formation of one or more metal monolayers at a potential positive of the reversible Nemst potential for bulk deposition. 

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