Ionic surfaces

Multiply charged ions such as adsorb on an ionic surface more strongly than singly charged ions such as Cl. The addition of a solution of... 

Poly(vinyl alcohol) will function as a non-ionic surface active agent and is used in suspension polymerisation as a protective colloid. In many applications it serves as a binder and thickener is addition to an emulsifying agent. The polymer is also employed in adhesives, binders, paper sizing, paper coatings, textile sizing, ceramics, cosmetics and as a steel quenchant. 

The curve shown in Fig. 6 for sodium dodecyl sulfate is characteristic of ionic surfactants, which present a discontinuous and sharp increase of solubility at a particular temperature [80]. This temperature is known as the Krafft temperature. The Krafft temperature is defined by ISO as the temperature [in practice, a narrow range of temperatures] at which the solubility of ionic surface active agents rises sharply. At this temperature the solubility becomes equal to the critical micelle concentration (cmc). The curve of solubility vs. temperature intersects with the curve of the CMC vs. temperature at the Krafft temperature. 

ISO 2270 1989, Non-ionic surface active agents. Polyethoxylated derivatives Iodometric determination of oxyethylene groups. 

Quaternary ammonium compounds (QACs Chapter 10) such as cetrimide, and also the bisbiguanide, chlorhexidine, are notoriously prone to promote clumping. A non-ionic surface-active agent of the type formed by condensing ethylene oxide with a long-chain fatty acid such as Cirrasol ALN-WF (ICI Ltd), formerly known as Lubrol W, together with lecithin, added to the diluting fluid has been used to overcome this effect. 

Thus, the HLB of an ionic surface-active substance is balanced at the standard ion-transfer potential. This is simply a reinterpretation of the definition of Aq P, but is a very important relation, which is valid no matter what the actual form of the adsorption... 

Wet anti-tack agents can be soap or detergent solutions or suspensions of the dry agents in water. For example, dissolved polymers with non-ionic surface active agents which form a thin layer of polymer on unvulcanised rubber sheets magnesium stearate in water zinc stearate dispersion and aqueous dispersions of fatty acid salts. 

High-performance liquid chromatography has, to date, only found limited applications in the analysis of sludges (aliphatic hydrocarbons, cationic and non-ionic surface active agents, carboxylic acids and cobalamin). 

The surfaces of colloidal particles are often charged and these changes can arise from a number of sources. Chemically bound ionogenic species may be found on the surface of particles such as rubber or paint latex particles. Charged species may be physically adsorbed if ionic surface active materials, for example, have been added. A charged surface may occur on a crystal lattice. An example is the isomorphous substitution of lower valency cations such as aluminium for silicon in the lattice structure of clays. A further example is the adsorption of lattice ions... 

Mulley, B.A. and Metcalf, A.D. Solubilization ofphenols by non-ionic surface active reagents, Sci. Pharm., 6 481-488,1966. 

The molecular geometry of phospholipid membranes is thus structurally analogous to inorganic phosphate minerals in that corrugated layers of metal ion-phosphate coordination complexes exist in membranes and minerals. In Fig. 5, the structure of a typical phosphate mineral is shown to reveal the type of molecular pattern that is exposed at the ionic surface of phospholipid membranes64,6S. For a recent review on membrane structure see66. ... 

Table 1. Attractive strength between cationic and ionic surfaces (N/cm2)... 

From the surface tension data obtained for different electrolyte concentrations, the relative ionic surface excesses can be determined. Thus, for the cell Hgl KC1 (aqueous)IHg2Cl2lHg, from Eq. (1.69), the cation excess is given by... 

We saw in Sec. V,5 that molecules with peripheral dipoles, such as OH, Nil, and, COOH groups are attracted strongly by the electrostatic field of the surface. These dipole forces form the most important contributions toward the adsorption energy when such molecules are adsorbed on ionic surfaces, nonpolar van der Waals forces and electrostatic polarization giving smaller contributions (133). 

The Heat of Adsorption as a Function of the Degree of Occupation in Physical Adsorption Phenomena on Ionic Surfaces... 

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