Oppositely charged polyelectrolytes, complex formation

Ulrich S, Seijo M, Stoll S (2006) The many facets of polyelectrolytes and oppositely charged macroions complex formation. Curr Opin Colloid Int Sci 11 268-272. doi 10.1016/j.cocis.2006.08.002... 

C. Monteux, C.E. WiUiams, J. Meunier, O. Anthony, and V. Bergeron Adsorption of Oppositely Charged Polyelectrolyte/Surfactant Complexes at the Air/Water Interface Formation of Interfacial Gels. Langmuir 20, 57 (2004). 

Miura N, Dubin PL, Mooiefield CN, Newkome GR. Complex formation by electrostatic interaction between carboxyl-terminated dendrimers and oppositely charged polyelectrolytes. Langmuir 1999 15 4245-4250. 

Polyelectrolyte complexes are formed by the ionic association of two oppositely charged polyelectrolytes [60,117-119]. Due to the long-chain structure of the polymers, once one pair of repeating units has formed an ionic bond, many other units may associate without a significant loss of translational degree of freedom. Therefore the complexation process is cooperative, enhancing the stability of the polymeric complex. The formation of polyelectrolyte complexes... 

Several other investigators have reported microencapsulation methods based upon polyelectrolyte complexes [289, 343]. For example, oppositely-charged polyelectrolytes (Amberlite IR120-P (cationic) and Amberlite IR-400 (anionic)) were recently used along with acacia and albumin to form complex coacervates for controlled release microcapsule formations [343]. Tsai and Levy [344,345] produced submicron microcapsules by interfacial crosslinking of aqueous polyethylene imine) and an organic solution of poly(2,6 dimethyl... 

Polyelectrolytes can be used to investigate intermolecular interactions because parameters such as ionic strength and concentration can be changed to monitor reactions between oppositely charged macromolecules. Upon formation of a polyelectrolyte complex, there is also the formation of a low molecular weight... 

Hayashi, Y., Ullner, M., Linse, P. (2003). Complex formation in solutions of oppositely charged polyelectrolytes at different polyion compositions and salt content. Journal of Physical Chemistry B, 107, 8198-8207. 

Coacervation. If an oil phase is emulsified in a polymer water solution, and the polymer is precipitated (for example) by changing the pH, the polymer precipitate (coacervate) has a tendency to accumulate at the interface. This is the coacervation process called simple if one polymer is involved and complex if two polymers are involved. If the coacervation is obtained by dropping one polymer solution into a polymer solution of opposite charge, this is termed interfacial coacervation, or polyelectrolyte complex formation . 

Nanostructures primarily result from polyelectrolyte or interpolyelectrolyte complexes (PEC). The PEC (also referred to as symplex [23]) is formed by the electrostatic interaction of oppositely charged polyelectrolytes (PE) in solution. The formation of PEC is governed by physical and chemical characteristics of the precursors, the environment where they react, and the technique used to introduce the reactants. Thus, the strength and location of ionic sites, polymer chain rigidity and precursor geometries, pH, temperature, solvent type, ionic strength, mixing intensity and other controllable factors will affect the PEC product. Three different types of PEC have been prepared in water [40] (1) soluble PEC (2) colloidal PEC systems, and (3) two-phase systems of supernatant liquid and phase-separated PEC. These three systems are respectively characterized as ... 

The exchange reactions between salts of polymer adds (bases) and weak polybases (polyadds) in aqueous solutions are accompanied by considerable pH changes and also by the appearance of turbidity, particularly if the components are mixed in equivalent quantities. The copredpitation of polymeric adds and polybases was described first by Fuoss and Sadek This behavior of the mixture of two oppositely charged polyelectrolytes can be explained by the formation of a polyelectrolyte complex, this reaction being accompanied by elimination of a low-molecular weight acid or base. Thus, the exchange reaction between poly(acrylic add) and pdly(4-vinyl-ethylpyridinium bromide) was shown by potentiometry and turbidimetry to result in the precipitation of an insoluble macromolecular product, i.e. the ionic comj ex, and... 

The degree of conversion describes whether the ionic sites of the component in deficiency are completely bound by the oppositely charged polyelectrolyte or low molecular counterions remain partly in the complex. Another characteristic quantity of a PEC is its end point stoichiometry, i.e., the molar ratio /E = [A ]E/[C+]E at the end of the complex formation reaction. However, this ratio may be different at other mixing ratios X, so that we have to introduce the stoichiometric factor/(A) = [A ]X/[C+]X to describe the overall composition of the PEC structures at any mixing ratio. 

The interaction between oppositely charged polyelectrolytes in aqueous environment leads to the formation of PECs. These PECs meet the profile of requirements of biocompatible polymer systems and can be adapted to meet the various requirements like carrier substances and components for active substances. The initial studies on macromolecular complexes were reported by Kossel. He described the formation of nucleoprotein complex due to interaction of proteins with nucleic acid and form heavy precipitates when mixed even at very high dilutions. In 1949, Fuoss and Sadek °... 

Both complex coacervation and interfacial polymerization can be used to create a polymer coating. Complex coacervation involves a phase separation that results from the formation of a complex between oppositely charged polyelectrolytes. At a pH below its isoelectric point gelatin, a positively charged collagen hydrolysis product has been widely used in complex coacervation with anionic species like gum Arabic, pectin and alginate. This approach has been used to prepare scratch... 

Storkle D, Duschner S, Heimann N et al (2007) Complex formation of DNA with oppositely charged polyelectrolytes of different chain topology cylindrical brushes and dendrimers. Macromolecules 40 7998-8006. doi 10.1021/ma0711689... 

As shown in Figure 5.12, these authors prepared a model for capsule formation. When SDS is added to the oil/water emulsion, complexation occurs between SDS and the oppositely charged polyelectrolyte (gelatin). This complex deposits at the oil droplet/water interface in the form of a primary layer (Fig. 5.12, B). Addition of the second polyelectrolyte (gum arabic) to the system induces further complexation between the two polyelectrolytes and covering of the primary layer surface. It is observed that the addition of surfactant (SDS) increases the encapsulation yield (Fig. 5.13). 

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