Macro-ion

More sophisticated approaches to describe double layer interactions have been developed more recently. Using cell models, the full Poisson-Boltzmann equation can be solved for ordered stmctures. The approach by Alexander et al shows how the effective colloidal particle charge saturates when the bare particle charge is increased [4o]. Using integral equation methods, the behaviour of the primitive model has been studied, in which all the interactions between the colloidal macro-ions and the small ions are addressed (see, for instance, [44, 45]). 

A mixture of polymers that can serve as a plugging solution when taken in an equimolar ratio consists of polydimethyl-di lyl ammonium chloride, which is a strongly basic cation-active polymer, and the sodium salt of carboxymethyl-cellulose, which is an anion-active polymer. The aqueous solution contains 0.5% to 4% of each polymer. Gelling occurs because the macro ions link together from different molecules. The proposed plugging composition has high efficiency within a wide pH range [497]. 

Bloomfield, V. A., Ma, C. and Arscott, P. C. in K. S. Schmitz (ed.), Macro-Ion Characterization from Dilute Solutions to Complex Fluids, American Chemical Society, Washington DC 1994, pp. 195-209. 

Only active species (e.g., macro radicals or macro ions) can add further monomer molecules in the propagation process. 

Dole, M. et al.. Molecular beams of macro ions.. Chem. Phys., 49,2240,1968. 

Rouzina, I. and Bloomfield, V. A. (1996) Macro ion attraction due to electrostatic correlation between screening counterions. I. Mobile surface-adsorbed ions and diffuse ion cloud. J. Phys. Chem., 100, 9977-9989. 

Dautzenberg H, Rother G, Hartmann J (1994) In Schmitz KS (ed) Macro-ion Characterization from Dilute Solutions to Complex Fluids. ACS Symposium Series 548 ACS, Washington DC p 219... 

Also, adsorption of macro-ions onto a (charged) surface may, in some cases, be described using the DLYO approach [33]. Then, depending on a system under consideration, the correlation effect, and, in particular, image forces, can play a significant role. 

Formation of electrostatic complexes means mutual neutralisation of the macro-molecular reactant. This mutual neutralization of opposite charges and formation of the concentrated complex coacervate phase, minimizes the electrostatic free energy and reduces both the hydrophilicity and the solubility of the resultant complex. The loss of entropy on complexing may be compensated by the enthalpy contribution from interactions between macro-ions and by liberation of counter-ions and water molecules. 

Normally, sufficiently concentrated solutions of biopolymers differing in chemical composition, conformation and affinity for a solvent are immiscible. Biopolymers are usually incompatible at a sufficiently high ionic strength and at pH values above the protein s lEP, where the biopolymers are charged macro-ions. These conditions are typical of most food systems. When the bulk concentration of the biopolymers is below the cosolubility threshold (or the phase separation threshold) the mixed solution of the biopolymers is stable. However, when the bulk biopolymer concentration is increased above this critical level, the mixed solution breaks down into two liquid phases. 

The quantitative studies of the termination by recombination of ions within a macro-ion pair and determination of the corresponding rate constants became possible by application of the end-capping method . ... 

Since this review was written a wealth of kinetic data on THF poly-menzations initiated by esters of trifluoromethyl sulphonic acid, fluoro-sulphonic acid and other super acids has appeared [164—168]. It has correctly been pointed out [167, 169] that secondary oxonium ions should not be observable separately under the experimental conditions of Pruckmayr and Wu [96] and that some of their NMR assignments are wrong. Instead, it has been verified that the observed spectrum corresponds to a very solvent sensitive equilibrium between a macro-ester and a macro-ion as proposed earlier by Smith and Hubin [98], viz. 

The theory of polyelectrolyte solutions was first developed for rigid macro-ions. The fundamental results obtained from this model are well discussed in the monograph published by Verwey and Overbeek in 1948 (29). Later, Levine, Booth, Kirkwood and a number of other investigators refined the fundamental work in various directions. ... 

The first applications of ESI in MS date from 1968. Dole et al. [5-6] investigated the possibility to transfer macromolecules from the liquid phase to the gas phase by electrospraying dilute solutions in a nitrogen bath gas. The hypothesis of Dole and cowoikers was that macro-ions can be produced by desolvating the charged droplets produced in electrospray. This ionization mechanism is called the charge residue model. 

Therefore, the present approach was initiated, together with the second virial coefficient, Bg, analyses. It was also shown for the first time (15) that in the case of ionic micelles, the Donnan term of Bg is proportional to the added salt concentration, mg1, as expected from theory. This relationship was valid only in those systems where the aggregation number, N, did not change appreciably with increased mg. It is thus obvious that ionic micelles must be treated as macro-ions (macromolecules). In the same context, we showed that B2 goes to zero as the temperature of non-ionic micellar solutions approaches this eloudpoint ("poor solvent") (15). 

Below, in Table Ill some typical data on dissociation of the macro- ion-pairs for both anionic and cationic ring--opening polymerization are given. 

The anionic polymerization of B-propiolactone in CH2CI2 led to the dependence of the ratio of reactivities of macro ions and macroion pairs on the solvating power of the medium (53). For higher proportions in the mixture of the more powerfully ion solvating component (B-propiolactone) the ratio of kp/ki decreased (at 350C kp/ki= =210 and 150 for the systems with 1bPL o=1 and 3 mol l respecively). Moreover, k in this system practically does not depend on the composition of the mixture and the decrease of the ratio is due to the decrease of kp (33)). We found also that the ratio of kp/k decreases also when the temperature is lowered, e.g. in a system with bPL o= =3 mol l" from 150 at 35°C to 5.6 at -20OC. ... 

Doty P, Steiner RF. Macro-Ions. I. Light scattering theory and experiments with bovine serum albumin. J Chem Phys 1952 20 85-94. 

Substances Nutrients (N and P) Suspended solids (transparency) Oxygen Temperature Chloride (salinity) Macro-ions (including bicarbonate) Significant discharges Specific pollutants (toxicity)... 

An understanding of the mechanisms of aluminum hydrolysis and the formation of crystalline species of aluminum hydroxide has been viewed as important in various fields of pure and applied chemistry, biochemistry, and geochemistry. In part, this interest results from the unique properties of certain hydrolysis species of aluminum that appear to be present as polymeric or polynuclear macro-ions. These ions have a strong positive charge and may interact with specific charge sites on surfaces they encounter. The polymeric species also may grow by accretion, and they may persist melastably for months or years under some conditions (1). 

In the models described in Sections 7.2. through 7.5., equilibrium between the adsorption layer and the adjacent subsurface is assumed. A generalisation, taking into account a Henry transfer mechanism as the relation between surface and subsurface concentration (cf Section 4.4), is given in Section 7.6. The special problems connected with the adsorption model of ionic surfactants as well as macro-ions is discussed in Sections 7.7. and 7.8. and an attempt to solve the boundary value problem numerically is demonstrated in Section 7.9. The few experimental results on ionic adsorption kinetics are reported in Section 7.10. 

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