Structure of polyelectrolyte complexes

Dautzenberg H, Hartmann J.Grunewald S, Brand F (1996) Stoichiometry and structure of polyelectrolyte complex particles in diluted solutions. Ber Bunsenges Phys Chem 100 1024-1032... 

This pronounced change in the UCST indicates a strong interaction between the two polymers. The addition of the polycation PDMAPAA-Q until R = 0.17 (where R signifies the molar ratio of polyelectrolyte/polyDMAPS) decreases the UCST first from 65 to 15 °C. The mixtures with the cationic ionenes show a similar evolution of the UCST, but also exhibit a minimum at K = 0.1-0.17. Thus, when polycations are added to 23b, the UCST decreases first, then passes through a minimum and increases again. This was attributed to the different geometrical structure of polyelectrolyte complexes (Scheme 19). 

Fig. 3. Schematic refH-esentation of the structure of polyelectrolyte complexes...

The PEC formation leads to quite different structures, depending on the characteristics of the component used and the external conditions of the reaction. As borderline cases for the resulting structures of polyelectrolyte complexes, two models (Figure 2) are discussed in the literature [23] ... 

Another type of functional nanocontainers can be fabricated by Layer-by-Layer assembly of oppositely charged species. Layer-by-Layer assembly of oppositely charged species was first proposed by Iler in 1966 [1] and later developed by Decher et al. [2]. The universal character of the method does not have any restriction on the type of the charged species employed for a shell construction. The precision of one adsorbed layer thickness is about 1 nm. The shell of the polyelectrolyte capsules is semipermeable and sensitive to a variety of physical and chemical conditions of the surrounding media, which might dramatically influence the structure of polyelectrolyte complexes and the permeability of the capsules. Introduction of nanosized metals (Ag, Au) or magnetic nanomaterials (Fe3O4) into the shell of polyelectrolyte capsules attains... 

Philipp B, Dautzenherg H, Linow K (1991) Formation and structure of polyelectrolyte complexes. Prog Polym Sci 14 91... 

Gardlund L, Wagberg L, Norgren M (2007) New insights into the structure of polyelectrolyte complexes. J Colloid Interface Sci 312 237-246... 

The properties and structure of polyelectrolyte multilayers are sensitive to a variety of physical and chemical conditions of the surrounding media which might dramatically influence on structure of polyelectrolyte complexes and result on permeability of the capsules. In particular. 

Many polymer-polymer complexes can be obtained by template polymerization. Applications of polyelectrolyte complexes are in membranes, battery separators, biomedical materials, etc. It can be predicted that the potential application of template polymerization products is in obtaining membranes with a better ordered structure than it is possible to obtain by mixing the components. The examples of such membranes from crosslinked polyCethylene glycol) and polyCacrylic acid) were described by Nishi and Kotaka. The membranes can be used as so-called chemical valves for medical applications. The membranes are permeable or impermeable for bioactive substances, depending on pH. 

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... 

Fig. 4a, b. Effect of the structure of the polycation component on the yield of polyelectrolyte complexes, (a) Pendant-type polycation (QPVP)-NaSS (b) Integral-type polycation (3 X)-NaSS ... 

The stability of PMAA-PVP complexes5 27 S7) has been investigated as a function of temperature, ionization of the polyelectrolyte component of the complex, and organic solvent. The complexes have been found to be very stable even at elevated temperature (Fig. 7, curve 4). The intrinsic viscosity is about 0.10 dl/g and does not depend on temperature up to 70 °C. The compact structure of the complex is retained up to some value of the degree of neutralization, the viscosity is low and does not change. As neutralization proceeds, the viscosity sharply increases and the PMAA-PVP system behaves as a usual polyelectrolyte (Fig. 8). It should be noted that the stabilization of the compact structure of the complex, due to complex formation, was also observed on the ionization of other systems52). 

Essafi W, Lafuma F, Williams CE. Structure of polyelectrolyte solutions at intermediate charge densities. In Schmitz KS, ed. Macro-ion Characterization. From Dilute Solutions to Complex Fluids. Washington DC ACS Symposium Series, 1994 278-286. 

Scattering methods provide detailed information about the structural parameters of colloidal particles. In the field of polyelectrolyte complexes, mainly light scattering techniques such as static, dynamic, and electrophoretic light scattering were employed. 

Li Y, Dubin PL, Dautzenberg H, Lueck U, Hartmann J, Tuzar Z. Dependence of structure of polyelectrolyte/micelle complexes upon polyelectrolyte chain-length and micelle size. Macromolecules 1995 28 6795—6798. 

Investigation of the Structure of Polyelectrolyte-Based Complex Coacervates and the Effects of Electrolyte Order of Addition... 

Tsuchida, E. Formation of polyelectrolyte complexes and their structures. J. Macromol. Sci. Pure Appl. Chem. 1994, 31 (1), 1-15. 

Mihai, M., Dragan, E.S., Schwarz, S., Janke, A. Dependency of particle sizes and colloidal stability of polyelectrolyte complex dispersions on polyanion structure and preparation mode investigated by dynamic light scattering and atomic force microscopy. J. Phys. Chem. B 2007, 111 (29), 8668-8675. 

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