Adsorption at liquid-solid interface

Figure C2.3.14. Isolated surfactant modes of adsorption at liquid-solid interfaces for a surfactant having a distinct headgroup and hydrophobic portion (dodecyltrimethylammonium cation) (a), (b) headgroup specific interaction ... 

The other way of removing plasticizers from water is their adsorption at liquid-solid interface (i.e., soil or sediments) [11]. This process depends on hydrophobicity of the substance, i.e. is proportional to organic carbon-water partition coefficient Kqq - plasticizers with Kqq value greater than 1000 dm /kg are regarded as having relatively significant affinity for sediments and son. It means that it is of greater importance in the case of 2-ethylhexyl (hydrophobic alkyl chain) than in the case of dimethyl phthalate (see Table 3). 

Taking account of all injected substance retention sources, i.e. (a) distribution between stationary and mobile phase (dissolution) (b) adsorption at the gas-liquid interface (c) adsorption at liquid-solid interface, and considering all retention mechanisms to be independent, Conder et al. [9] have established the number of moles of solute retained on length dL of a column of length L in equilibrium with a concentration c in the gas phase ... 

V. Chan, S.E. McKenzie, S. Surrey, P. Fortina, and DJ. Graves, Effect of hydrophobidty and electrostatics on adsorption of DNA oligonucleotides at liquid/solid interfaces. J. Coll. Interf. Sci. 203, 197-207 (1998). 

The determination of adsorption isotherms at liquid-solid interfaces involves a mass balance on the amount of polymer added to the dispersion, which requires the separation of the liquid phase from the particle phase. Centrifugation is often used for this separation, under the assumption that the adsorption-desorption equilibrium does not change during this process. Serum replacement (6) allows the separation of the liquid phase without assumptions as to the configuration of the adsorbed polymer molecules. This method has been used to determine the adsorption isotherms of anionic and nonionic emulsifiers on various types of latex particles (7,8). This paper describes the adsorption of fully and partially hydrolyzed PVA on different-size PS latex particles. PS latex was chosen over polyvinyl acetate (PVAc) latex because of its well-characterized surface PVAc latexes will be studied later. 

As a technique for selective surface illumination at liquid/solid interfaces, TIRF was first introduced by Hirschfeld(1) in 1965. Other important early applications were pioneered by Harrick and Loeb(2) in 1973 for detecting fluorescence from a surface coated with dansyl-labeled bovine serum allbumin, by Kronick and Little(3) in 1975 for measuring the equilibrium constant between soluble fluorescent-labeled antibodies and surface-immobilized antigens, and by Watkins and Robertson(4) in 1977 for measuring kinetics of protein adsorption following a concentration jump. Previous rcvicws(5 7) contain additional references to some important early work. Section 7.5 presents a literature review of recent work. 

There is good evidence that proteins adsorbed from solutions onto some solid surfaces form films in which the molecules remain predominantly in the compact configuration, are unoriented at the interface (6, 7), or may not unfold at liquid/solid interfaces (8). Protein adsorption onto synthetic polymer surfaces is important because of its possible... 

The restriction photoisomerization of stilbene at liquid-solid interface provides an interesting illustration of a situation where the influence of adsorption and the influence on reaction are coupled effects . ... 

L. E. Smith and R. S. Stromberg, Polymers at Liquid-Solid Interfaces, Loughborough, 1975. E. Killmann, J. Eisenlauer, and M. Korn, The adsorption of macromolecules on solid/liquid interfaces, Polym. Symp. 61, 413 (1978). 

The adsorption of proteins from aqueous solution to solid surfaces is the result of a combination of hydrophobic, steric, and electrostatic interactions between the protein, solid surface, and solution [ 1-3]. Numerous studies have been conducted to identify the driving forces governing protein adsorption and dynamics at liquid-solid interfaces and have been reviewed elsewhere [4—8], In the adsorbed state, protein stmcture is likely to be perturbed (Figure 15.1). The unfolded or partially unfolded protein can then adopt various flexible conformations depending on the natures of the solid surface the protein [1, 4, 9-13]. While this has been exploited for various applications [12], uncontrolled adsorption can cause protein degradation, compromised function, and even life-threatening immunogenic responses. The molecular mechanisms of protein adsorption have not been fully elucidated and remain a current area of research [ 10]. 

Chan V, Graves D, Fortina P, McKenzie SE (1997) Adsorption and surface diffusion of DNA oligonucleotides at liquid/solid interfaces. Langmuir 13 320-329... 

SEIRA and SERS are powerful techniques for stmctural characterization of ultra thin films and well-ordered monolayer on metal surfaces. Thin films at interfaces are prepared by different procedures and developed for various applications. The fabrication and characterization of ultra thin films is a permanent area of research where some of the most interesting subjects are (a) bilayers and monolayers at liquid-liquid interface, (b) adsorption monolayers and Langmuir (water-insoluble) monolayers at air-water interface, (c) adsorption films and self-assembled monolayers (SAMs) at liquid-solid interface and Langmuir-Blodgett Alms, cast (deposit) films and spin-coat films at air-solid interface. Studies about molecular organization of monolayers of porphyrins derivatives, of azamacrocy-cles and their metallic derivatives among the many SEIRA applications to films and interfaces, were published . 

In addition to the contributions above, i.e. adsorption at liquid-gas interface and modification of the polymer structure in the film deposited on support, the adsorption at a liquid-solid interface (polymer-support) can also lead to an apparently lower degree of crystallinity than the real one [123]. 

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. ... 

Langmuir adsorption coefficient overall mass transfer coefficient individual mass transfer coefficients at G-L interface ibid, at liquid-solid interface homogeneous reaction velocity... 

Understanding and predicting the assembling behaviors of multi-component mixtures on solid surfaces is very challenging because of the formation of complex assemblies such as superlattice structures and quasi-crystals on surfaces. In this section, we describe the formation of superlattice structures at liquid-solid interfaces by co-adsorption of two structurally similar molecules, i.e., DBA-OCn bearing alkoxy chains that differ by only one methylene unit, via synergetic interactions between mutual components. Since DBA-OCn at the monocomponent level exhibits an odd-even effect related to molecular chirality that is an origin of superlattice formation, we will start with a discussion on the odd-even effect on molecular self-assemblies on surfaces. 

There has been a general updating of the material in all the chapters the treatment of films at the liquid-air and liquid-solid interfaces has been expanded, particularly in the area of contemporary techniques and that of macromolecular films. The scanning microscopies (tunneling and atomic force) now contribute more prominently. The topic of heterogeneous catalysis has been expanded to include the well-studied case of oxidation of carbon monoxide on metals, and there is now more emphasis on the flexible surface, that is, the restructuring of surfaces when adsorption occurs. New calculational methods are discussed. 

Volume 10 Adsorption at the Gas-Solid and Liquid-Solid Interface. Proceedings of an International Symposium, Aix-en-Provence, September 21-23,1981 edited by J. Rouquerol and K.S.W. Sing... 

Section 8 deals with reactions which occur at gas—solid and solid—solid interfaces, other than the degradation of solid polymers which has already been reviewed in Volume 14A. Reaction at the liquid—solid interface (and corrosion), involving electrochemical processes outside the coverage of this series, are not considered. With respect to chemical processes at gas-solid interfaces, it has been necessary to discuss surface structure and adsorption as a lead-in to the consideration of the kinetics and mechanism of catalytic reactions. 

To evaluate the time-dependent function, X(t), a simple model of diffusion is proposed. Starting from Langmuir adsorption theory, we consider that liquid molecules having diffused into the elastomer are localized on discrete sites (which might be free volume domains). In these conditions, we can deduce the rate of occupation of these sites by TCP with time. Only the filhng of the first layer of the sites situated below the liquid/solid interface at a distance of the order of the length of intermolecular interaction, i.e., a few nanometers, needs to be considered to estimate X(t). 

Volume 10 Adsorption at the Gas-Sdid and Liquid-Solid Interface. Proceedings of an... 

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