Surfactants infrared spectroscopy

As for other surfactants [239], infrared spectroscopy can also be used as a quick method for the identification of ether carboxylates [238]. 

Gordon, L.M., Lee, K.Y.C., Lipp, M.M., Zasadzinski, J.A., Walther, F.J., Sherman, M. A., and Waring, A.J. Conformational mapping of the N-terminal segment of surfactant protein B in lipid using C-13-enhanced Fourier transform infrared spectroscopy. J. Peptide Res. 

Vandenbussche G, Clercx A, Clercx M, et al. Secondary structure and orientation of the surfactant protein SP-B in a lipid environment. A Fourier transform infrared spectroscopy study. Biochemistry 1992 31(38) 9169-9176. 

Islam MT, Rodriguez-Hornedo N, Ciotti S, Ackermann C. Fourier transform infrared spectroscopy for the analysis of neutralizer-carbomer and surfactant-carbomer interactions in aqueous, hydroalcoholic, and anhydrous gel formulations. AAPS J 2004 6(4) arti-... 

In THE PAST DECADE, IMPROVEMENTS IN infrared spectroscopic instrumentation have contributed to significant advances in the traditional analytical applications of the technique. Progress in the application of Fourier transform infrared spectroscopy to physiochemical studies of colloidal assemblies and interfaces has been more uneven, however. While much Fourier transform infrared spectroscopic work has been generated about the structure of lipid bilayers and vesicles, considerably less is available on the subjects of micelles, liquid crystals, or other structures adopted by synthetic surfactants in water. In the area of interfacial chemistry, much of the infrared spectroscopic work, both on the adsorption of polymers or proteins and on the adsorption of surfactants forming so called "self-assembled" mono- and multilayers, has transpired only in the last five years or so. 

Fourier-transformed infrared spectroscopy (FT1R), either in the transmission mode(70), the grazing incidence reflection (GI) mode(7,5) or the attenuated total reflection (ATR) mode(7,2), has been the most widely used experimental tool for the characterization and structure determination of SA monolayers. GI-IR is especially useful in determining the molecular orientation in the film structures because it senses only the vibrational component perpendicular to the substrate surface(7,5). Polarized ATR-IR can also be used to study molecular orientation(7,77). McKeigue and Gula-ri(72) have used ATR-IR to quantitatively study the adsorption of the surfactant Aerosol-OT. 

The surface forces technique measures the force between molecules (eg. surfactants, polymers) adsorbed on mica sheets. In the case of large molecules such as polymers, the measurement is most sensitive to the regions closest to the solution and provides little direct information about the region adjacent to the surface. As it is a measurement between macroscopic surfaces, it is unable to provide information on microscopic chemical differences at the interface. Infrared spectroscopy could provide additional information about the quantity of adsorbed material on the mica surface, the identity and orientation of the adsorbed species, and possibly the nature of the surface linkage. 

Cassidy and Niro [13] have applied high-speed liquid chromatography combined with infrared spectroscopy to the analysis of polyoxyethylene surfactants and their decomposition products in industrial process waters. Molecular sieve chromatography... 

C. Roll, J. Knief, S. Horsch, and L. Hanssler, Effect of Surfactant Administration on Cerebral Haemodynamics and Oxygenation in Premature Infants—a Near-Infrared Spectroscopy Study, Neuropediatrics, 31(1), 16-23 (2000). 

For colloids with a physically adsorbed surfactant or cca, the adsorption isotherm is important. The adsorbant concentration on the particle surface can be measured by infrared spectroscopy using diffuse reflectance and by ESCA. Absolute concentrations are difficult to determine with ESCA on "rough" surfaces, and a calibration point is required with other techniques. The change of the concentration of adsorbant in solution after adsorption on the colloid surfaces can be detected by elemental analysis of supernatant with plasma emission or atomic absorption if adsorbant contains specific element(s). When colloids are sterically stabilized, the effectiveness of the stabilization can be evaluated with solvent-nonsolvent techniques and with temperature studies ( 25,26). 

Evidence presented thus far for the putative role played by the photoliberated surfactants has been somewhat circumstantial. Conventional infrared and ultraviolet spectroscopy establish that the photolabile protecting group is photolyzed and the surfactant released under photolysis acid-base indicators, when added to the photosensitive coating, confirm the release of acid for the anionic surfactant derivatives. The surface sensitive spectroscopic techniques of ESCA (Electron Spectroscopy for Chemical Analysis) and RAIR (Reflection-Absorption Infrared) spectroscopy establish the involvement of the surfactant more unequivocally. 

Spectroscopic methods are also commonly used for the analysis of surfactants. Among these methods ultraviolet/visible spectrophotometry and infrared/near-infrared spectroscopy are used for the measurement of surfactant concentration, while such techniques as nuclear magnetic resonance (NMR) and mass-spectroscopy (MS) are extensively used for... 

Spectroscopic methods, such as fluorescence recovery and quenching, Fourier-transform infrared spectroscopy (FT-IR), and light reflection technique have been used for studies of adsorbed proteins (for example Burghardt Axelrod 1981, Thompson et al. 1981, van Wagenen et al. 1982), and surfactant adsorption layers (for example Ldsche et al. 1983, L6sche Mohwald 1989, Daillant et al. 1991, Henon Meunier 1992, Mohwald 1993). Considerable progress has been made in recent years with respect to the sensitivity of detectors and the efficiency of computers, so that the power of these methods has increased remarkably. 

Mesoporous alumina samples have been synthesized using poly(ethylene oxide)-based nonionic surfactants. The effect that the addition of n-alkylamines to the synthesis gel has on the texture and thermal stability of mesoporous aluminas is studied. Textural and structural characterization using nitrogen adsorption, powder X-ray diffraction, a1 nuclear magnetic resonance and Fourier Transform infrared spectroscopy, as well as catalytic n-hexane hydroisomerization tests are performed. 

Debe, M.K. "Organic/Metal Interface Studies with Reflection-Adsorption Infrared Spectroscopy Photomarked Surfactants and Organic Photoconductors on Aluminum", Appli. of Surf. Sci., 14,... 

Concerning water control, there should also be mentioned the question of estimation of the hydration level of initial surfactant preparations (which should be taken into account in order to calculate correctly the degree of hydration). For this purpose, we used infrared spectroscopy to control the water content at a frequency of 3420 cm (the method is described in detail in Ref. 22). 

Couzist, A., Gulari E. (1993). Adsorption of sodium laurate from its aqueous solution onto an alumina surface. A dynamic study of the surface-surfactant interaction using attenuated total reflection Fourier transform infrared spectroscopy, Langmuir Vol. 9, 3414-3421, 0743-7463. 

Chemical interactions The chemical contribution may result from interactions such as covalent or complex bond formation between the surfactants and the surface sites. Surfactants such as fatty acids, alkyl sulfates, alkyl sulfonates, amines and alkylhydroxa-mates have been proposed to adsorb by means of chemical interactions on a variety of particles. In addition, surfactants containing hydroxyl, phenolic, carboxylic and amine groups can hydrogen-bond with the surface sites. Infrared spectroscopy has been used to understand the chemisorption of surfactants at the surface, by examining the shift in the characteristic peaks of the surfactants upon adsorption. 

Infrared spectroscopy (both IR and Fl lR) has been used in some cases (e.g., anionic surfactants... 

Structure studies of diyne surfactants are complicated by the fact that single crystals — whenever obtained — are extremely thin and fragile and rapidly polymerize in the X-ray beam. Thus a full structure analysis of any of the compounds either as a monomer or polymer is still lacking up to the present All informations on structure and structure changes during polymerization are based on morphological studies by polarizing and electron microscopy as well as structure studies by electron diffraction infrared spectroscopy . ... 

Supercritical fluid chromatography (SEC) coupled with Fourier transform infrared spectroscopy has been used to determine polymeric surfactants in various polymers [56, 57]. 

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