Polyelectrolytes

Abstract

Polyelectrolytes are polymers that develop substantial charge when dissolved or swollen in a highly polar solvent medium such as water. The attendant electrostatic interactions — within a single polyelectrolyte, between polyelectrolytes, or with molecules/surfaces — produce physical properties much different than those for neutral polymers. Most polyelectrolyte solution and gel properties vary sharply with addition of simple electrolytes, which screen electrostatic interactions according to concentration. Scientists are just beginning to understand polyelectrolyte electrostatic interactions, which are known to play an important role in the natural world. Important concepts for polyelectrolytes are counterion condensation, electrostatic persistence length, electrostatic excluded volume, and Donnan equilibrium. Properties such as low angle scattered intensity, solution viscosity, osmotic pressure, polyelectrolyte and counterion diffusion coefficients, conductivity, adsorption, complexation, electric and magnetic birefringence, electrophoresis, titration, and gel swelling can only be understood by accounting properly for electrostatic interactions. These distinctive properties underlie applications in colloid stabilization, surface modification, rheology control, and controlled release.

PFG‐NMR diffusometry: A tool for investigating the structure and dynamics of noncommercial purified pig gastric mucin in a wide range of concentrations

“…In a way, this can be referred to as the ''normal'' polyelectrolyte effect and a strong charge repulsion tends to increase the viscosity. 28 On further increase of the pH, the opposite trend is seen and the rheological parameters again decrease. Although this result appears strange at first sight, a similar observation has been reported for a synthetic hydrophobically modified polyelectrolyte.…”

Phase Behavior of Ion-Containing Polymers in Polar Solvents: Predictions from a Liquid-State Theory with Local Short-Range Interactions

“…In the category of ionic polymers, there are anionic polymers, cationic polymers, and ampholytic polymers [ 5 ]. If a substantial portion of the constitutional units contains ionic or ionizable groups, or both, such ion-containing polymers are often called polyelectrolytes [ 6 , 7 ]. According to Hoagland [ 7 ], charged polymers possessing only a low density of charged units along their backbones, with the fraction of these units typically less than about on a mole basis, are often referred to as ionomers.…”

“…If a substantial portion of the constitutional units contains ionic or ionizable groups, or both, such ion-containing polymers are often called polyelectrolytes [ 6 , 7 ]. According to Hoagland [ 7 ], charged polymers possessing only a low density of charged units along their backbones, with the fraction of these units typically less than about on a mole basis, are often referred to as ionomers. The ionic groups that endow ionic polymers are no different than those found in small organic molecules bearing charges.…”

“…The list of cationic groups includes, e.g., protonated ammonium, quaternized ammonium, sulfonium, and phosphonium groups. For summaries of chemical structures of those ionizable or ionic groups, interested readers are directed to the reviews by Hoagland [ 7 ], Mecerreyes [ 8 ], and more recently Kocak et al [ 9 ] and Ofridam et al [ 10 ].…”

Viscosity of Polyelectrolyte Solutions: Experiment and a New Model

“…Consequently, polyelectrolyte solutions have special dual properties, showing the general characteristics of both neutral polymer and electrolyte solutions. Recently, polyelectrolytes have become increasingly important in chemical industries, biological processes, material sciences, and so forth. , Nevertheless, the understanding of their properties is far from complete, primarily because of the complex long-range electrostatic polyion−polyion and polyion−counterion interactions. For instance, as one of the important transport properties, the viscosity of polyelectrolyte solutions is not fully understood, although toward that end, there have been a large number of studies.…”