Polyelectrolyte macroion complex

Boroudjeidi, H., Netz, R.R. Interactions between polyelectrolyte-macroion complexes. Europhys. Lett. 64, 413-419 (2003)... 

H. Wang, M. Roman, Formation and properties of chitosan—cellulose nanocrystal polyelectrolyte-macroion complexes for drug delivery applications. Biomacromolecules 12 (2011)1585-1593. 

Skerjanc J, Kogej K. Electrical transport in polyelectrolyte-surfactant complex solutions at various degrees of complexation. In Schmitz KS, ed. Macroion Characterization. From Dilute Solutions to Complex Fluids. Washington ACS, 1994 268-275. 

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... 

The Monte Carlo simulations were applied to study the complexation, phase separation, and redissolution of polyelectrolyte-macroion solutions [128]. It was shown that introduction of the oppositely charged polyelectrolytes into a stable macroion solution with repelling macroions resulted in a decrease in the solution stability. The system was unstable at macromolecular charge equivalence when a large and loose cluster of macroions and polyelectrolytes was forming. Finally, redissolution of macroions occurred in the excess of polyelectrolyte. 

Transfer of electrons can naturally lead to changes in the charge (valency) of the redox-active species. Therefore, it is an obvious consequence to study the interaction of switchable counterions with macroions [228] or other multiple-charged objects like polyelectrolytes [229]. The group of Anson was one of the first to investigate the complexation of electrochemically switchable counterions with strong polyelectrolytes [230-232]. In some cases, the cationic polysiloxanes became insoluble through oxidation of complexed ferrocyanide. The polyelectrolyte-counterion complex then deposited onto the electrode as a thin... 

In addition to theoretical works, some experimental papers have been published recently which are devoted to the study of polyelectrolyte complexes formed by macroions with oppositely charged networks [50-52]. Also, in recent publications by Osada interpolymer complexes (I PC) were described which are formed by the networks of PMAA with polyethylene glycol) (PEG) and some other polymers [53-55]. 

An important effect not taken into account by the various models discussed in Sect. 2 is the specific interactions of the counterions with the macroion. It is well-known that counterions may even be complexated by macroions and these effects have been discussed abundantly in the early literature in the field [24]. From the above discussion it now becomes clear that these effects must be traced back to specific effects which are not related to the electrostatic interaction of counterions and macroions. Hence, hydrophobic interactions related to subtle changes in the hydratation shell of the counterions could be responsible for this small but significant discrepancy of the electrostatic theory and experiment. Further studies using the PPP-polyelectrolytes will serve for a quantitative understanding of these effects which are outside of the scope of the present review. 

In general, depending on the nature of the polyelectrolytes, the response of a PEC to subsequent addition of salt may be quite different (see also [82-85]). The authors of [86] propose to use the different salt stability of the ionic binding to separate polyelectrolyte components from mixtures via complex formation with oppositely charged macroions. 

Dautzenberg H, Rother G, Hartmann J. Light scattering studies of polyelectrolyte complex formation effect of polymer concentration. In Schmitz KS, ed. Macroion Characterization From Dilute Solution to Complex Fluids. ACS Symposium Series 548. Washington, DC American Chemical Society, 1994 210-224. 

Abstract Aqueous solutions of star-like polyelectrolytes (PEs) exhibit distinctive features that originate from the topological complexity of branched macromolecules. In a salt-free solution of branched PEs, mobile counterions preferentially localize in the intramolecular volume of branched macroions. Counterion localization manifests itself in a dramatic reduction of the osmotic coefficient in solutions of branched polyions as compared with those of linear PEs. The intramolecular osmotic pressure, created by entrapped counterions, imposes stretched conformations of branches and this leads to dramatic intramolecular conformational transitions upon variations in environmental conditions. In this chapter, we overview the theory of conformations and stimuli-induced conformational transitions in star-like PEs in aqueous solutions and compare these to the data from experiments and Monte Carlo and molecular dynamics simulations. 

Anoflier interesting effects are flie changes of a polyelectrolyte in binary solvents. The complex inter and intramolecular interactions that take place due to the presence of hydrophilic and hydrophobic structural units in the macroion can modify the balance of the interactions and for this reason can change flie solubility. ... 

More complex systems such as solutions containing macroions and short flexible coimterions have recently been simulated using the primitive model of electrolytes [112]. Solutions of macroions with simple coimterions at different amounts of oppositely charged polyelectrolyte have also been investigated, and the sequence complexation phase separation redissolution was observed [113]. Similar simulations where the macroion represented lysozyme have also been performed [114]. Finally, by using a related soft-sphere model, the dynamics and, in particular, the self-diffusion of the macroions and the counterions have been investigated by employing Brownian dynamics simulation [115]. 

Activation volumes for base hydrolysis of the complexes a- and P-[Co(edda)(NH3)2] " and a-[Co(edda)(N02)2r, +16.6, +22.3, and +11.9cm mo respectively, are claimed all to be consistent with the operation of the 5n1CB mechanism for base hydrolysis. Activation volumes for base hydrolysis of the [Co(NH3)5Br] cation are smaller in aqueous polyelectrolytes than in water, but are still markedly positive. Activation volumes and entropies suggest that the effect of the macroions is to dehydrate the 2 + reactant. There is a correlation of activation volumes and activation entropies for a variety of substitutions of this type in polyelectrolytes compare the earlier correlation of activation volumes and entropies for a range of substitutions in aqueous solution. 

Polyelectrolytes (PEs) are polymers with charged monomer groups that can dissociate into a charged macroion and small counterions when the PE is dissolved in a polar solvent [1, 2]. These charged polymers are, in many cases, employed in nature, and not only DNA [3] but also proteins and cellulose can be classified as PEs. Technical applications of PEs include, for example, PE-DNA drug delivery complexes called polyplexes [4, 5]. The interaction and structure of PEs in a solvent (mostly water) are controlled to a large extent by electrostatic interactions. 

An independent justification has been given by Oosawa [8] who has shown that additivity is a consequence of the properties of the integrated coulomb potential of the macroion. The approximate nature of the Rule is recognized in Oosawa s treatment, and it would seem, by analogy with the development of the present understanding of low molecular weight electrolyte mixtures, that departures from additivity when carefully assessed would be more truly revealing of the complex interactions between a polyelectrolyte and added salt. 

---