Attenuated total reflectance chemical structures

Gaboury, S. R. Urban, M. W. Analysis of Gas-Plasma-Modified Poly(Dimethylsiloxane) Elastomer Surfaces. Attenuated-Total-Reflectance-Fourier Transform Infrared Spectroscopy. In Structure-Property Relations in Polymers Urban, M. W., Graver, C. D., Eds. Advances in Chemistry Series 236 American Chemical Society Washington, DC, 1993 pp 777-790. 

The primary techniques used in this study include X-ray photoelectron spectroscopy (XPS), reflection-absorption infrared spectroscopy (RAIR), and attenuated total reflectance infrared spectroscopy (ATR). XPS is the most surface-sensitive technique of the three. It provides quantitative information about the elemental composition of near-surface regions (< ca. 50 A sampling depth), but gives the least specific information about chemical structure. RAIR is restricted to the study of thin films on reflective substrates and is ideal for film thicknesses of the order of a few tens of angstroms. As a vibrational spectroscopy, it provides the type of structure-specific information that is difficult to obtain from XPS. The... 

More significantly, when calorimetry is combined with an integral kinetic analysis method, e.g. a spectroscopic technique, we have an expanded and extremely sophisticated method for the characterisation of chemical reactions. And when the calorimetric method is linked to FTIR spectroscopy (in particular, attenuated total reflectance IR spectroscopy, IR-ATR), structural as well as kinetic and thermodynamic information becomes available for the investigation of organic reactions. We devote much of Chapter 8 to this new development, and the discussion will focus on reaction calorimeters of a size able to mimic production-scale reactors of the corresponding industrial processes. 

Spectroscopic methods are mainly useful to identify the elements, functional groups, and chemical structures close to the biomaterial surface. Techniques like X-ray photoelectron spectroscopy, attenuated total reflection fourier transform infrared spectroscopy, and secondary ion mass spectrometry have been used widely in determining the elemental composition and charged species at biomaterial surface. Other important characteristics obtained from the biomaterial surface are surface energy and relative wettability using thermodynamic method such as contact angle experiments. 

Vibrational spectroscopy is a molecule-specific analytical method that probes the vibrations of molecules and solids. Fourier transform infrared (FTIR) and Raman spectroscopies are widely used in situ techniques in the analysis of chemical reactions. However, in the case of silicalite-1 synthesis, they have not yet been used [35]. Attenuated total reflectance infrared (ATR-IR) spectroscopy has however been used to study soluble silicates and shown to be able to characterize various structures [25, 35-37]. It is likely only a matter of time before we see ATR-IR used under in situ conditions. 

J. M. Fang, PA. Fowler, J. Tomkinson, and C.A.S. Hill, The prepcffation cuid characterisation of a series of chemically modified potato starches. Carbohydr. Polym. 47,245-252 (2002). J.J.G. Van Soest, H. Tournois, D. de Wit, and J.F.G. Vliegenthart, Short-rcUige structure in (partially) crystalline potato starch determined with attenuated total reflectance Fourier-transform IR spectroscopy. Carbohydr. Res. 279, 201-214 (1995). 

Attenuated total reflection (ATR) spectroscopy is one of the most widely used techniques for surface infrared analysis. Although the phenomenon of total internal reflection of light was described by Newton in the early 17th century, it was not until much later that Harrick and, independently, Fahrenfort were to exploit this phenomenon to obtain absorption spectra and develop the ATR technique. When applied to the study of in situ kinetics of adsorption and reaction of species at liquid/ solid interfaces, ATR spectroscopy can yield valuable surface-chemical data. Such studies have been carried out in a variety of research and technological areas, including biomembranes, biofilms, thin film structure and reactivity, and electrochemistry. ... 

The NR/PS blend sheet was dried in an oven at 50 °C for 24 h and kept in a desiccator before being further characterized. The chemical structure of the NR/PS blend sheet was analysed by an Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) Bruker EQUINOK 55 measuring in the range of 4000-500 cm ... 

The microstructure of zso-phthalate polyester films before and after exposure at room temperature to an alkaline solution was studied using tapping mode atomic force microscopy (AFM) [133]. The results of structural characterization as well as chemical analyses using attenuated total reflection FT-IR, total carbon analysis and liquid chromatography-mass spectroscopy showed that the base-catalyzed hydrolysis of polyester was a heterogeneous process. The formation of pits occurs as a result of hydrolysis and the number and size of pits increases with exposure time. 

Fourier transform infrared-attenuated total reflectance (FTIR, ATR-FTIR, Nicolet 8700, USA) spectroscopy was used to analyze the chemical structures of the specimens. All spectra were collected with 4 cm wavenumber resolution after 64 continuous scans at a wavelength range of 4000—600 cm ... 

IR absorption, emission, and reflection spectra for molecular species either in solid, liquid, or gas phases arise mostly from various changes in energy due to transitions of molecules from one vibrational or rotational energy state to another. The frequency or wavelength of this energy transition is characteristic of the specific chemical bond vibration and/or rotation in the molecule which are determined by the molecular structure, the masses of the atoms, and the associated vibrational energy coupling. Attenuated total reflectance (ATR) and reflection-mode of IR in conjunction with electrochemical methods allow samples to be examined directly in the solid or liquid state without further preparation and are widely used in the characterization of electrode-electrolyte interface properties. Most of ILs are IR-active molecules. Since ILs are stable and chemically inert, the IR characterization can be easily performed on the IL-based system directly. 

The chemical structure of the membrane can be analyzed with spectroscopic methods, of which the Fourier transform infrared spectroscopy attenuated total reflectance (FTIR-ATR) method is the most utilized. However, Raman spectroscopy and IR spectroscopy complement each other, and, thus, if both methods arc used, the information obtained on the membrane chemical structure is quite comprehensive. If only information from the membrane skin layer is needed, the most surface-sensitive methods—X-ray photoelectron spectroscopy (XPS) and lime-of-flight secondary ion mass spectroscopy (TOF-SIMS)— have to be used. 

The chemical interaction of organosihcon compounds and copolymers of etltylene with vinyl acetate and copolymers of ethylene with viityl acetate and maleic anhydride was studied by IR spectroscopy absorption and Attenuated Total Reflection (ATR). An emichment of the surface layers of polymers by siloxane phase was found, that may be useful in the design of the chemical structure of adhesive materials for different purposes. 

Attenuated total reflection (ATR) is a useful method to study the surface structural of PFSA membrane, and it can circumvent the film thickness problem. Liang found that v XCFj), Vs(CF2), and v/SO) of ATR spectra are red shifted by 20.4, 10.7, and 4.8 cm" compared with that of transmission IR, which indicates that chemical environment is different for membrane surface and bulk. ... 

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