Poly electrolyte adsorption

Muthukumar, M. Theory of counter-ion condensation on flexible poly electrolytes adsorption mechanism. J. Chem. Phys. 120, 9343 (2(X)4)... 

PR. Van Tassel, Poly electrolyte adsorption and layer-by-layer assembly Electrochemical control. Current Opinion in Colloid Interface Science, 17 (2012) 106-113. 

From the experiments it is clear that poly electrolyte is adsorbed on the surface of the black lipid film. This applies both to the experiments with gelatin and bovine serum albumin, which gave no decrease of film resistance, and to the experiments with bovine erythrocyte ghost protein and polyphosphate. The adsorption of protein on the phospholipid-water interface may be controlled independently by investigating the electrophoretic behavior of emulsion droplets, stabilized by phospholipid, in a protein solution, as a function of pH. In this way Haydon (3) established protein adsorption on the phospholipid-water interface. If the high resistance (107 ohms per sq. cm.) of black lipid films is to be ascribed to the continuous layer of hydrocarbon chains in the interior of the film, as is generally done, an increase in film conductivity is not expected from adsorption without penetration. 

Adsorption of Poly electrolytes with Hydrophobic Parts... 

The manipulation of the adsorption of surfactants at the air-solution interface by polymers and poly electrolytes has been extensively studied [17], and has... 

Polyelectrolytes The most striking feature of polyelectrolytes is that, due to the electrostatic repulsion between the segments, the formation of thick adsorbed layers is prevented. Poly electrolytes tend to adsorb in rather flat conformations. If adsorbent and polyelectrolyte bear opposite charges, this attraction can be of an electric (Coulombic) natufe if the charges have the same sign, adsorption takes place only if the nonelectrostatic attraction outweighs the electrostatic repulsion (Lyklema, 1985). 

Photoreaction 63 Photosynthesis 171 Plastic sulfur 43 Poly electrolytes 174 Polymer adsorption 174 -, preparation 87 -, rate of formation 90 -, structure 42 Polymerization theory 81 Polysulfanes 92-93 Polysulfide 176, 179, 183 -, oxidation 184... 

FIG. 12 Adsorption of a poly electrolyte (zp = — 1) on an uncharged surface as a function of time for various 1-1 electrolyte concentrations (indicated as volume fractions Balt). In (a) the adsorption is given for short times, in (b) for long times (on a logarithmic scale). Endpoints in (b) are for equilibrium adsorption and a polymer concentration of 300 mg L 4 (poiymer = 1CT4). (Calculated data from Ref. 14.)... 

With new data for polyelectrolytes obtained with the techniques described above it should become possible to determine carefully the effects of ionic strength and externally controlled surface potential on the rate of adsorption of poly electrolytes. We hope that the effects of molar mass and charge density of the poly electrolyte, as well as the nature of that charge (annealed or quenched) can be established. This should stimulate further theoretical research aimed at constructing an adequate equivalent of the Von Smolu-chowsky-Fuchs theory for the rate of flocculation. At present, it would seem that an analysis of the adsorption process taking all complications into account necessitates a simulation-oriented approach. 

In combination with adsorption measurements, electro-optics is proved to be a powerful technique for studying the structure of adsorbed polyelectrolyte layers. Our data show flat conformation of the adsorbed macromolecules, which slightly depends on the polyelectrolyte charge density in accordance with the theory for weak poly electrolytes. Counterion condensation is also suggested on the surface of weakly charged poly electrolytes, which has not been predicted from the theory. 

First, it is the experimental and theoretical (including computer modeling) investigation of adsorption layers formed on solid surfaces by natural and synthetic polymers, especially by poly electrolytes. Such studies, and in particular those involving the use of Atomic Force Microscopy (AFM, see Chapter VII), provide important information regarding the optimal conditions for the use of polymers for flocculation or stabilization of disperse systems (Chapter VII), and establish the theoretical basis for understanding the mechanism behind the action of structural-mechanical barrier. 

Ultrathin functional films can be prepared with finely adjusted film thickness and properties by a layer-by-layer (LbL) method. Such multilayers are fabricated by the alternated adsorption of anionic and cationic poly electrolytes. These poly electrolyte multilayers are self-compensated in terms of the charge however, the introduction of redox ions such as Fe(CN)g orOs(bpy) + is also possible [126]. 

A new class of PS core/magnetite shell particles was produced by the sequential adsorption of magnetite nanoparticles and polyelectrolyte, a process that allowed the shell thickness and composition to be controlled with nanometer precision. The poly electrolytes were poly(diallyldimethylammonium chloride) or poly(allylamine hydrochloride). The influence of an external magnetic field on ordering of the composite PS core/magnetic shell particles was examined. 22 refs. 

Because of their widespread use and well-recognized interfacial activity, we first consider the adsorption of ionic surfactants as a model for the adsorption of poly electrolytes (polycations) and examine the dominant forces and factors governing the phenomenon ... 

Decher, G., Hong, J. D., Schmitt, J. (1992). Buildup of ultrathin multilayer films by a self-assembly process 3. Alternating adsorption of anionic and cationic poly electrolytes on charged surfaces. Thin Solid Films, 210(1-2), 831-835. 

Neivandt, D. J. in Co-adsorption of poly electrolytes and surfactants at the silica-solution interface A spectroscopic study, PhD thesis. (The University of Melbourne, Melbourne), (1998). 

Kumar, R., Kundagrami, A., and Muthukumar, M., 2009. Counterion adsorption on flexible poly electrolytes Comparison of theories. Macromolecules, 42, 1370-1379. 

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