Polyelectrolytes in solution

Our observation should be important in understanding these properties of polyelectrolytes in solutions and perhaps in gels. 

H. E. Eisenberg, Biological Macromolecules and Polyelectrolytes in Solution, Chap. 4, Oxford University Press, Oxford, 1976. 

If we take into consideration that the lowest experimentally possible polyelectrolyte concentration cp is approximately 10 6 monomol L 1, it follows from Table 8 that the diluted solution state, cp 2000, i.e. if Mn >320,000 g-mol The theoretical treatment and the experimental studies of the concentration dependent behavior of polyelectrolytes in solution is usually restricted to the case with or without an excess of a low molecular electrolyte. A relatively limited amount of data exist for similar concentrations of polyelectrolytes and low molecular mass salt [97]. 

Interactions of polyelectrolytes in solution and at interfaces are of predominantly Coulombic nature [27,150]. However, other interactions including dipol-di-pol, charge-transfer, and hydrophobic effects also have to be considered [27,151, 152]. Table 13 demonstrates general characteristics of interactions of polycations with oppositely charged species which can be applied to PDADMAC. 

The fact that Poisson-Boltzmann theory overestimates the osmotic coefficient is well-known in literature. Careful studies of typical flexible polyelectrolytes in solution ([2, 23] and further references given there) indicated that agreement of the Poisson-Boltzmann cell model and experimental data could only be achieved if the charge parameter was renormalized to a higher value. To justify this procedure it was assumed that the flexible polyelectrolytes adopt a locally helical or wiggly main chain in solution. Hence,... 

Holm C, Kremer K (1999) Polyelectrolytes in Solution—Recent Computer Simulations. In Noda I, Kokufuta E (eds) Proc Yamada Conf Polyelectrolytes 1998. Yamada Science Foundation, Osaka, Japan, p 27... 

An interesting analogous in vitro experiment was performed by Xu el al. [92] in which the presence of a polyelectrolyte in solution resulted in a layer of amorphous calcium carbonate forming under a structured monolayer. This subsequently transformed into a thin layer of polycrystalline calcite. The crystal growth in this in vitro system occurs by phase transition of amorphous calcium carbonate into calcite and not by dissolution of amorphous phase and reprecipitation of calcite crystals. 

---