Organic-surface interactions

Chapter 1 is a view of the potential of surface forces apparatus (SFA) measurements of two-dimensional organized ensembles at solid-liquid interfaces. At this level, information is acquired that is not available at the scale of single molecules. Chapter 2 describes the measurement of surface interactions that occur between and within nanosized surface structures—interfacial forces responsible for adhesion, friction, and recognition. 

The experimental data bearing on the question of the effect of different metals and different crystal orientations on the properties of the metal-electrolyte interface have been discussed by Hamelin et al.27 The results of capacitance measurements for seven sp metals (Ag, Au, Cu, Zn, Pb, Sn, and Bi) in aqueous electrolytes are reviewed. The potential of zero charge is derived from the maximum of the capacitance. Subtracting the diffuse-layer capacitance, one derives the inner-layer capacitance, which, when plotted against surface charge, shows a maximum close to qM = 0. This maximum, which is almost independent of crystal orientation, is explained in terms of the reorientation of water molecules adjacent to the metal surface. Interaction of different faces of metal with water, ions, and organic molecules inside the outer Helmholtz plane are discussed, as well as adsorption. 

Graber ER, Borisover M (2005) Exploring organic compound interactions with organic matter the thermodynamic cycle approach. Colloid Surface A 265 11-22... 

Gustafson RL, Paleos J (1971) Interactions responsible for the selective adsorption of organics on organic surfaces. In Faust SJ, Hunter JV (eds) Organic compounds in aquatic environments. Marcel Dekker, New York, pp 213-237... 

Inoue et al. (2003) found that silk proteins will form rodlike structures and that those structure will assemble into comblike or fabric-like superstructure. The scale differences between the rods (nanometers) and the superstructure (micrometers) would suggest that the rod formation is governed by amyloid fibril formation and that the supramolecular arrangement is governed by the properties of the rod (Oroudjev et al., 2002 Putthanarat et al., 2000), namely surface interaction and hydration. Three levels of association could be considered (i) within the proteins internal /1-strands will organize to form intra /1-sheet structures, (ii) /1-sheets from neighboring molecules will associate to form fibril subunits, and (iii) the fibril subunits will further associate to form larger fibrils or rods. 

Due to the usual diversity of components in the medium, there will be a need to consider that the species taken up interacts with other species while diffusing towards the organism surface (see Figure 19). In some cases (as in the aquatic prokaryotes that exudate Fe chelators called siderophores to improve the availability of Fe see Chapter 9 in this volume), the medium is modified on purpose by the organisms [11,47-49], A simple model for this interaction assumes the complexation of M with a ligand, with elementary interconversion kinetics between the free and complexed forms ... 

Adsorption chromatography is generally considered suitable for the separation of nonionic molecules that are soluble in organic solvents. Very polar compounds, those with high solubility in water and low solubility in organic solvents, interact very strongly with the adsorbent surface and result in peaks of poor symmetry and poor efficiency. 

Petit C, Bandosz TJ Enhanced adsorption of ammonia on Metal-Organic Framework / graphite oxide composites analysis of surface interactions, Adv. Fund. Mater. 2009,19,1-8. 

Types of metal adsorption to mineral and organic surfaces (a) outer sphere interactions, (b) adsorption by electron-donor groups, (c) adsorption by negatively charged surface sites, and (d) adsorption to surface groups capable of forming metal-covalent bonds. The only parts of the molecular structure of the particle shown are the atoms engaged in metal adsorption. 

Most solutions used in electrodeposition of metals and alloys contain one or more inorganic or organic additives that have specific functions in the deposition process. These additives affect deposition and crystal-building processes as adsorbates at the surface of the cathode. Thus, in this chapter we first describe adsorption and the factors that determine adsorbate-surface interaction. There are two sets of factors that determine adsorption substrate and adsorbate factors. Substrate factors include electron density, d-band location, and the shape of substrate electronic orbitals. Adsorbate factors include electronegativity and the shape of adsorbate orbitals. 

Approximately 40 to 50% of the total amount of phenolics sorbed was retained by the organic matter fraction (27). In surface soil layers, organic matter is frequently intimately associated with the mineral components present, providing a large surface area and reactive sites for surface interaction. Soil acidity has a major influence on phenolic adsorption by the organic carbon fraction, since the degree of dissociation of the phenolic acids is pH-dependent. Whitehead and coworkers (28) observed that the extractability of several phenolic acids was highly dependent upon the extractant pH between pH 6 and 14. The amount extractable continually increased with extractant pH thus the extracted acids could not be readily classified into distinct fractions. 

Walker AV, Tighe TB, Haynie BC, Uppili S, Winograd N, Allara DL (2005) Chemical pathways in the interactions of reactive metal atoms with organic surfaces vapor deposition of Ca and Ti on a methoxy-terminated alkanethiolate monolayer on Au. J Phys Chem 109 11263-11272... 

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