Atomic force microscopy chemical sensitivity

The materials analyzed were blends of polystyrene (PS) and poly(vinyl methyl ether) (PVME) in various ratios. The two components are miscible in all proportions at ambient temperature. The photooxidation mechanisms of the homo-polymers PS and PVME have been studied previously [4,7,8]. PVME has been shown to be much more sensitive to oxidation than PS and the rate of photooxidation of PVME was found to be approximately 10 times higher than that of PS. The photoproducts formed were identified by spectroscopy combined with chemical and physical treatments. The rate of oxidation of each component in the blend has been compared with the oxidation rate of the homopolymers studied separately. Because photooxidative aging induces modifications of the surface aspect of the material, the spectroscopic analysis of the photochemical behavior of the blend has been completed by an analysis of the surface of the samples by atomic force microscopy (AFM). A tentative correlation between the evolution of the roughness measured by AFM and the chemical changes occurring in the PVME-PS samples throughout irradiation is presented. 

Spectroscopy (IR), Raman Spectroscopy, X-ray Photoelectron Spectroscopy (XPS) or Electron Spectroscopy for Chemical Analysis (ESCA), and Secondary Ion Mass Spectrometry (SIMS). More recently. Atomic Force Microscopy (AFM) has also found important use in the characterization of the local surface distribution of paper. Below, we will briefly discuss the use of some different surface-sensitive techniques in paper applications and relate the results obtained to paper characteristics and end-use properties. For a more detailed description of these and other available techniques for characterizing the chemistry of paper surfaces, readers are referred to ref. (60). 

Elemental and molecular surface chemistry plays an important role in the acceptance of an implant material [2-12]. In the study of the elemental and chemical composition of polymeric surfaces, XPS, secondary ion mass spectrometry (SIMS), and surface energy evaluations have emerged as the dominant methods for surface analysis. This is due to the ability of XPS to provide qualitative and quantitative elemental and chemical information (10-100 A), which is complemented by the molecular information obtained from SIMS over the outermost 5-25 A. Surface wettability measurements provide a rapid and quantitative measurement of the inherent surface wettability of a solid sample. When these measurements are accompanied by a Zisman plot, the polarity and critical surface tension (7. ) of the solid surface may be determined. The critical surface tension is a measure of the surface free energy (yj of solid materials. The surface morphology of the lenses studied here was investigated through the use of atomic force microscopy (AFM). The sensitivity of the technique allows submicrometer (to Angstroms) sized features to be examined. 

From a methodological point of view, of particularly interest have been improvements in the chemical sensitivity of STM and AFM characterization. This is especially desirable for electrochemists, as electrochemical environments prevent the combined characterization by other surface techniques, as are frequently used for composition determinations in vacuum. Tunneling spectroscopy measurements to obtain 7 y and d//dV y relationships may provide a certain degree of information regarding the electronic structure of the substrate surface and adsorbed molecules [77], and the use of ionic liquids of large electrochemical windows is favorable in this respect. One major enhancement would be to complement SPM with other spatial, time- and energy-resolved surface in-situ techniques. For example, a combination of scanning electrochemical microscopy and atomic force microscopy... 

The Case of Chemically Sensitive Imaging of Surfaces by Atomic Force Microscopy... 

If we set out to unravel surface chemical functionalities with high spatial resolution down to atomic detail, we also encounter various practical (technical) problems. It is fair to say that the technique development for direct space analysis (again, we exclude Fourier space methods) is still lagging much behind. Chemical force microscopy can be considered as a first step in the direction of a true description of surface chemical functionalities with high spatial resolution in polymers, primarily based on the chemically sensitive analysis of AFM data via adhesion mapping. At this point the detailed theory for force spectroscopy is not developed beyond the description of London forces. The consideration of the effect of polar functional groups in force spectroscopy (similar to difficulties with solubihty parameter and surface tension approaches for polar forces, as well as specific interactions) is still in its infancy. Instead, one must still rely on continuiun contact mechanics to couple measured forces and surface free energies. 

BASIL CIS CV CVD DSSC ECALE EC-STM EDX, EDS, EDAX EIS EMF EQCM FAB MS FFG-NMR Biphasic Acid Scavenging Utilizing Ionic Liquids Copper-indium-selenide Cyclic Voltammetry Chemical Vapor Deposition Dye Sensitized Solar Cell Electrochemical Atomic Layer Epitaxy Electrochemical in situ scanning tunnelling microscopy Energy Dispersive X-ray analysis Electrochemical Impedance Spectroscopy Electromotive Force Electrochemical Quarz Crystal Microbalance Fast atom bombardment mass spectroscopy Fixed Field Gradient Nuclear Magnetic Resonance... 

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