Polyelectrolyte

Polyelectrolyte properties are thus similar to both electrolytes (salts) and polymers (high molecular weight compounds) and are sometimes called polysalts.

polyelectrolyte: Polymer composed of macromolecules in which a substantial portion of the constitutional units contains ionic or ionizable groups, or both.

Since the polyelectrolyte dissociation releases counter-ions, this necessarily affects the solution's ionic strength, and therefore the Debye length.

These polymers usually only dissolve when sufficient added salt screens the interactions between oppositely charged segments.

In the case of amphoteric macroporous hydrogels, the action of concentrated salt solution does not lead to the dissolution of polyampholyte material due to the covalent cross-linking of macromolecules.

Synthetic 3-D macroporous hydrogels shows the excellent ability to adsorb heavy-metal ions in a wide range of pH from extremely diluted aqueous solutions, which can be later used as an adsorbent for purification of salty water[5][6] All proteins are polyampholytes, as some amino acids tend to be acidic, while others are basic.

Polyelectrolytes have many applications, mostly related to modifying flow and stability properties of aqueous solutions and gels.

There is currently much research on using biocompatible polyelectrolytes for implant coatings, controlled drug release, and other applications.

During each dip, a small amount of polyelectrolyte is adsorbed, and the surface charge is reversed, allowing the gradual and controlled build-up of electrostatically cross-linked films of polycation-polyanion layers.

LbL films can also be constructed by substituting charged species such as nanoparticles or clay platelets[8] in place of or in addition to one of the polyelectrolytes.

An LbL formation of PEM (PSS-PAH (poly(allylamine) hydrochloride)) on a gold substrate can be seen in the Figure.

The formation is measured using multi-parametric surface plasmon resonance to determine adsorption kinetics, layer thickness, and optical density.

Because of its connectivity, the behavior of the polyelectrolyte chain bears almost no resemblance to that of confined, unconnected ions.

In polymer terminology, a polyacid is a polyelectrolyte composed of macromolecules containing acid groups on a substantial fraction of the constitutional units.