Charge density of polyelectrolytes

Polyelectrolyte with oppositely charged surfactant is a new working area. Many researches are interested in the interaction between polyelectrolyte and ionic surfactant in bulk solution. A complex can be formed with the interaction of polyelectrolyte chain-surfactant. Association of polyelectrolyte and surfactant starts at a well-defined surfactant concentration whereas it finishes at the critical aggregation concentration (CAC). CAC system is affected by polyelectrolyte concentration, charge density of polyelectrolyte, flexibility. CAC is inversely proportional to charge density and flexibility [25]. 

The effect which polyelectrolyte adsorption has upon the surface charge (zeta potential) of fibres and fines is also important—particularly for retention—and both molecular weight and charge density of the adsorbed polyelectrolyte are known to affect the particle surface charge, although not always in an intuitively predictable way. 

Anionic polyelectrolytes with a high charge density of hydroxyl and carboxyl groups... 

In this paper, a two-dimensional model is proposed, in which the polyelectrolyte chains are treated as rigid cylinders normally grafted to each of the plates. On the surface of the cylinders, ionizable sites are uniformly distributed and the surface charge of the cylinder is generated through their dissociation. Using this two-dimensional model, the repulsive force between two plates is calculated as a function of electrolyte concentration, surface density of polyelectrolyte chains on the plate, thickness of the polyelectrolyte brushes, and bulk pH (denoted in what follows as pHo). 

While the covalent bonding of polymers on oxide surfaces requires certain reaction conditions adapted for the particular reaction system, for example highly purified non-aqueous solvents or thermally activated surface groups, surface modification with polyelectrolytes can be carried out in aqueous environment [31-46]. Numerous parameters can be adjusted to control the conformation of the polyelectrolyte molecules, e.g. their charge density and the charge density of the metal oxide surface. In other words, the adsorption process and the surface properties of the final product can be influenced in many different ways. This diversity is a challenge for academic research to develop novel hybrid materials for technical applications. 

A structurally well-defined and water-soluble PVAm is available by acid or base catalyzed hydrolysis of PVFA (Scheme 2) [58, 59] because form-amide groups are readily hydrolyzed to amino groups. The degree of hydrolysis of PVFA can be used to produce adaptable copolymers, poly(vinyl form-amide-co-vinyl amine) (PVFA-co-PVAm) with different formamide/amino group ratios. Hence, the degree of hydrolysis of the formamide groups is an excellent tool to control the desired charge density of the polyelectrolyte. 

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