Oppositely charged polyelectrolytes, complex

Any pair of oppositely charged polyelectrolytes capable of forming a Hquid complex coacervate can be used to form microcapsules by complex... 

Polymer complexes associated with two or more complementary polymers are widely used in potential applications in the form of particles, hydrogels, films, and membranes. In particular, a polyion complex (PIC) can be easily formed when oppositely charged polyelectrolytes are mixed in aqueous solution and interact via... 

The following guidelines can be utilized for the preparation of stable microcap-sular membranes from the complex coacervation of oppositely charged polyelectrolytes. 

Polyelectrolyte complexes formed by polyion pairing are of special interest, including protein-polyelectrolyte interactions such as protein-DNA complexes. A special case of polyelectrolyte complexes are polyelectrolyte multilayers (PEM) on surfaces formed by ion pairing, van der Waals interactions and counterion release of oppositely charged polyelectrolytes [2, 3]. 

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... 

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. 

A variational theory which includes all these different contributions was recently proposed and applied for completely stretched polyelectrolyte stars (so-called porcupines ) [203, 204]. As a result, the effective interaction V(r) was very soft, mainly dominated by the entropy of the counterions inside the coronae of the stars supporting on old idea of Pincus [205]. If this pair potential is used as an input in a calculation of a solution of many stars, a freezing transition was found with a variety of different stable crystal lattices including exotic open lattices [206]. The method of effective interactions has the advantage to be generalizable to more complicated complexes which are discussed in this contribution-such as oppositely charged polyelectrolytes and polyelectrolyte-surfactant complexes-but this has still to be worked out in detail. 

Oppositely charged polyelectrolytes interact with each other to form polyelectrolyte complexes in solution, the possible combinations including strong poly-acids-strong polybases, strong polyadds-weak polybases, weak polyadds-strong polybases, weak polyadds-weak polybases, or polyampholytes. Consid-... 

Studies on the interaction between oppositely charged polyelectrolytes date back to 1896 when Kossel389 precipitated egg albumin with protamine. Since that time extensive studies have been made on pairs of strong polyelectrolytes, pairs of strong and weak polyelectrolytes, pairs of weak polyelectrolytes, as well as on amphoteric complexes. However, the theoretical considerations of intermacromolecular interactions between polyelectrolytes were only based on extremely simplified model systems. However, even in the case of such systems, there are many unsolved problems such as the determination of the local dielectric constant in domains of macromolecular chains, the evaluation of other secondary binding forces, especially hydrophobic interactions, and so on. 

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 complexes of poly(methyl methacrylate) stereoisomers or polymeric adds with nonionic hydrophilic polymers, the complexes between oppositely charged polyelectrolytes or of biological macromolecules and synthetic high molecular weight substances are known. Reactions involving polyelectrolytes24,25) have been studied most extensively. However, only little is known about the complexes with coordinate bonds28,159). 

Interpolymer, polymer-surfactant, and coordination complexes of polybetaines are less developed. The cascade -type complexation observed for the polybetaine-polyelectrolyte system is similar to the layer-by-layer deposition found for oppositely charged polyelectrolytes. The behavior of the polybetaine-surfactant system differs from that of polyelectrolyte-surfactant and polyampholyte-surfactant complexes, leading to inter- or intramolecular comicellization or converting the whole macromolecule to either a polycation or polyanion. 

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... 

Fig. 4 Principles of complex aqueous coaeervation (A) Oppositely charged polyelectrolytes (B) polyelectrolyte/ multivalent counterions.

Complexes formed by interaction of oppositely charged polyelectrolytes... 

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