POLYELECTROLYTE

CAS NUMBER: 42751-79-1

Polyelectrolytes are widely used as dispersants for high solids loaded colloids (>50 vol%). 
They combine principles of EDL and steric stabilization, or electrosteric stabilization, and they depend on pH and ionic strength. 

At low solids loading (~20 vol%), viscosity is relatively low, and it is affected very little by pH changes. 
As solids loading increases, however, pH affects viscosity significantly. 

The amount of added Polyelectrolyte also has a profound effect on colloidal rheology. 
Polyelectrolyte should be optimized to just saturate the surface. 

Additional Polyelectrolytes result in excess amounts of polymer in the system, and excess polymer can cause depletion flocculation in high solids loaded systems.
Conformation of adsorbed Polyelectrolyte also plays an important role in rheological behavior of electrosterically stabilized colloids, and, in turn, Polyelectrolyte conformation depends on the system’s pH. 

A detailed study of adsorption behavior on Al2O3 shows that Polyelectrolyte adsorption on particles increases as pH decreases. 
Typically, a 10-fold increase of adsorbed amount is observed from the uncharged to the charged state. 

When pH increases or decreases beyond zero charge, the fraction of the Polyelectrolyte dissociated moves toward 1. 
Hence, charges in the Polyelectrolyte rePolyelectrolyte each other and the molecule stretches. 

At this moment, two models exist: the charged Polyelectrolyte adsorbs flat on the surface or the Polyelectrolyte adsorbs in a tail-like brush structure.
Conformation shape of the adsorbed Polyelectrolyte highly influences dispersion quality. 

Which types of structures – flat, pancake-like, or brush-like – are achieved depends on adsorption conditions and the materials involved. 
For pancake-like adsorption, the polymer only contributes short-range repulsive force, and EDL forces of the charged Polyelectrolyte mainly contribute to stabilization via long-range interactions. 

For brush-style structures, the repulsion is much stronger, and true electrosteric contributions are present. 
Polyelectrolytes can also be used as dispersants when they are uncharged, i.e. at their PZC. 

However, they will favor coil-like conformations. 
Hence, much higher molecular weights will be needed to achieve thicker layers of adsorbed polymer coils, and steric forces predominantly contribute to stabilization.

Polyelectrolyte complex holds a great deal of promise for the formation of inhibitor containers sensitive to the pH. 
Since there are various possibilities to change the permeability of Polyelectrolyte multilayers, the use of Polyelectrolyte complexes can control the interior of containers. 

Owing to the presence of hydroxyl groups on the surface of most inorganic NPs, the majority of these particles are negatively charged at the surface; thus, oppositely charged layers of Polyelectrolyte can be alternatingly deposited on the material through electrostatic interaction to prevent undesirable leakage of inhibitor. 
The release of additives with corrosion-inhibiting function, similar to the layer-by-layer Polyelectrolyte corrosion-protective coatings, is controlled by varying the pH level, which changes the layer-by-layer Polyelectrolyte permeability. 

In noncross-linked linear Polyelectrolytes, the Polyelectrolyte complexes, due to displaying electrostatic nature, are highly sensitive to the ionic strength and pH. 
If two types of strong Polyelectrolytes constitute a Polyelectrolyte complex, the obtained complex displays stability in a wide range of pH values and is able to be opened by raising the ionic strength of the solution and release the confined material. 

Conversely, if weak Polyelectrolytes constitute the Polyelectrolyte complex, the obtained complex can be damaged and destroyed by shifting the local pH to acidic for weak polyanions and to alkine for weak polycations. 
The Polyelectrolyte complex consisting weak and strong Polyelectrolytes displays sensitivity to the shift in the pH in only one direction, meaning that weak polyacid together with strong polybase can be used only for the release of inhibitors in acidic media and weak polyacid together with strong polybase for the release of inhibitors only in alkine media, whereas the Polyelectrolyte complex composed of two weak Cationic polyelectrolytes constitutes a container shell, which displays sensitivity to the shift in the pH in both regions. 

Consequently, the Polyelectrolyte shell of corrosion inhibitor carriers is able to prevent leakage of the corrosion inhibitor at nearly neutral pH and achieve smart release properties when corrosion commences with an alkine and acidic shift in the pH. 
The fabrication of inhibitor nanoreservoirs with sensitivity to either anodic or cathodic process or to both processes is possible by varying the Polyelectrolyte shell material. 

Polyelectrolyte shell using layer-by-layer method on the mesoporous silica NPs surface loaded with [2-(benzothiazol-2-ylsulfanyl)-succinic acid]. These NPs were doped in the sol–gel coating. 
The permeability of the shell increased in response to the alkaline and acidic region at the corroded surface, leading to releasing inhibitors. 
In addition, the zirconia–silica-based hybrid coating containing these NPs exhibited improved long-term protection against corrosion elements. 

The submicrometer containers constructed by this method exhibited higher corrosion inhibitor loading efficiency. 
The pH-triggered release of corrosion inhibitor as well as barrier effects of the matrix increased the corrosion protection performance.

Polyelectrolyte membranes are synthesized on surface of the charged supports via sequential coating of anionic and cationic Polyelectrolytes. 
This assembly technique named as layer by layer (LbL) is attractive for the preparation of NF and RO membranes, and the obtained dense structure can limit passage of ions through the membranes. 

In this method, first, the initially charged membrane is soaked in the positive dilute solution of cationic Polyelectrolyte. 
After that the membrane is removed from the solution and rinsed with water for elimination of the unbound molecules. 

Then the obtained positively charged membrane is immersed in the negative dilute solution of anionic Polyelectrolyte followed by water rinsing. 
In each step, a small content of Polyelectrolytes adsorbs on the membrane surface and consequently the previous charge of the membrane reverses. 

Multiple positive and negative layers onto the membrane surface cause the preparation of Polyelectrolyte multilayer membranes. 
The number of formed Polyelectrolyte layers has an essential role in water flux and salt rejection of the Polyelectrolyte membranes. 

The higher number of the layers increases mass transfer resistance so water flux decreases. 
On the other hand, salt rejection increases with increment of the deposited dense Polyelectrolyte layers. 

Polyelectrolyte is worth noting that there are an optimum number of layers that determine the membrane performance. 
The separation performance, thickness, surface hydrophilicity, and charge of the LbL membranes are affected by type, concentration, pH, and the layer number of the Polyelectrolytes.

Polyelectrolytes are macromolecules that, when dissolved in a polar solvent like water, have a (large) number of charged groups covalently linked to them. 
In general, Polyelectrolytes may have various kinds of such groups. 

Homogeneous Polyelectrolytes have only one kind of charged group, e. g. only carboxylate groups. 
If both negative (anionic) and positive (cationic) groups occur, we call such a molecule a polyampholyte. 

These Polyelectrolytes will only be briefly discussed at the end of this chapter. 
Self-assembled structures, such as linear micelles or linear protein assemblies, also often have many charged groups; these structures may have properties very similar to those of Polyelectrolytes, but we shall not deal with them in this chapter.

Special properties of Polyelectrolytes, as compared with uncharged polymers, are their generally excellent water solubility, their propensity to swell and bind large amounts of water, and their ability to interact strongly with oppositely charged surfaces and macromolecules. 
Because of these features, they are widely used as rheology and surface modifiers. 

These typical Polyelectrolyte properties are intimately related to the strong electrostatic interactions in Polyelectrolyte solutions and, hence, are sensitive to the solution pH and the amount and type of electrolytes present in the solution.
Polyelectrolytes show many applications in fields, such as in water treatment as flocculation agents, in ceramic slurries as dispersant agents, and in concrete mixtures as super-plasticizers. 

Furthermore, many shampoos, soaps, and cosmetics contain Polyelectrolytes. 
Certain Polyelectrolytes are also added to food products, for example, as food coatings and release agents. 

Some examples of Polyelectrolytes are pectin (polygalacturonic acid), alginates (alginic acid), and carboxymethyl cellulose, of which the last one is of natural origin. 
Polyelectrolytes are water soluble, but when crosslinking is created in Polyelectrolytes they are not dissolved in water. 

Crosslinked Polyelectrolytes swell in water and work as water absorbers and are known as hydrogels or superabsorbent polymers when slightly crosslinked. 
Polyelectrolytes are ionizable polymers that change their polymeric conformations upon their environmental changes. 

They are of two types: strong and weak Polyelectrolytes. 
Strong Polyelectrolytes are charged over a wide pH range. 

Hence, Polyelectrolyte is a difficult task to manipulate the properties of the assembled film unless one takes specific measures to disturb the polymer-polymer interactions by controlling other stimuli such as ionic strength, temperature, and polarity. 
Unlike strong Polyelectrolytes, weak Polyelectrolytes are charged only in a smaller pH window; hence, their polymeric conformations can be easily modulated upon changing the pH of the external environment. 

The unique feature of PEM films assembled from weak Polyelectrolytes is that they can be destroyed at extreme pH conditions as the pH-induced charge imbalances in the film overcompensate the attractive polymer-polymer interactions.
Polyelectrolytes (PEL) are polymers that carry charges within their backbone or in side chains. 

Usually, discrimination is made between weak and strong Polyelectrolytes.
Weak Polyelectrolytes are polymers with weakly acidic or basic groups, which are protonated or deprotonated depending on the pH of the surrounding medium, resulting in a pH-dependent charge density. 

In contrast, the charge density in strong Polyelectrolytes is not influenced by the pH.
Polyelectrolyte brushes exhibit interesting characteristics with respect to both theoretical and practical aspects because their behavior is fundamentally different from that of uncharged polymer brushes. 

In the case of strong Polyelectrolyte brushes, in which the charge density is independent of the pH, the molecular structure and properties are dominated by electrostatic interactions. 
Mutual repulsion between charged polymer segments strongly influences the physical properties of the grafted layers. 

In weak Polyelectrolyte brushes—in which the charge density of the chains depends on their protonation level—the chain conformation depends on the pH of the solution. 
In particular, the swelling of weak Polyelectrolyte brushes in different solvents was extensively studied due to its importance for responsive polymer systems. 

Swelling depends on the nature of the solvent system, as well as its pH and the concentration and chemical nature of other ions in the solution. 
Furthermore, interactions with selected counterions can be used to tune the wettability of surfaces with anchored Polyelectrolyte brushes.

Polyelectrolytes are polymers possessing many ionizable groups. 
The combination of polymeric and electrolyte behaviour gives them a number of useful properties, as indicated in Table 1, but also poses problems of characterization. 

This chapter provides an introduction to the behaviour of Polyelectrolytes in solution, discusses the difficulties which this behaviour engenders in the determination of molecular weights and considers means of overcoming these difficulties.
Polyelectrolytes are polymers with ionizable repeating groups, such as polyanions and polycations. 

These groups can dissociate in polar solvents such as water, leaving charges on polymer chains and releasing counterions into the solution. 
Polyelectrolyte complexes (PECs) offer the possibility of combining physicochemical properties of at least two Polyelectrolytes. 

The PECs are formed by strong electrostatic interactions between oppositely charged Polyelectrolytes, leading to interpolymer ionic condensation and the simultaneous release of counterions. 
Other interactions between two ionic groups to form PEC structures include hydrogen bonding, hydrophobic interactions, van der Waals’ forces, or dipole–dipole charge transfer.

Water soluble, and can also dissolve completely in cold water.
Add a small amount of anionic polyelectrolyte products, you can receive a lot of flocculation effect.

while using the products and inorganic anion polyelectrolyte flocculant (polymerized ferric sulfate, polyaluminum chloride, iron salts, etc), you can display a greater effect.
Polyelectrolyte is added to the sludge line during the pumping of the excess activated sludge taken from the sedimentation pond to filter presses or belt-presses to dewater the sludge.

Polyelectrolyte is widely used in sludge dewatering units of wastewater treatment plants.
In processes where sludge dewatering is performed with a centrifuge decanter, belt press or filter press, the flocculant, which is mixed with the help of a static mixer, is dosed into the pressurized sludge line.

The working principle of the Polyelectrolyte product is generally based on ion exchange between the polymer chain in aqueous solution and the electrical charges of the suspended solid particles. 
The stable structure of solid particles deteriorates, which leads to coagulation or flocculation.

Polyelectrolytes are diluted from 0.05% to 0.1%. The preparation solution is usually prepared at 0.5% by adding the original product to water while mixing. 
Since the characteristics of the sludge to be dewatered are different, the dosages to be applied are determined as a result of jar test and operation trials in the laboratory.

If Polyelectrolyte chains are added to a system of charged macroions, an interesting phenomenon called the Polyelectrolyte bridging might occur. 
The term bridging interactions is usually applied to the situation where a single Polyelectrolyte chain can adsorb to two (or more) oppositely charged macroions (e.g. DNA molecule) thus establishing molecular bridges and, via its connectivity, mediate attractive interactions between them.

At small macroion separations, the chain is squeezed in between the macroions and electrostatic effects in the system are completely dominated by steric effects – the system is effectively discharged. 
As we increase the macroion separation, we simultaneously stretch the Polyelectrolyte chain adsorbed to them. 

The stretching of the chain gives rise to the above-mentioned attractive interactions due to chain's rubber elasticity.
Polyelectrolytes have been used in the formation of new types of materials known as Polyelectrolyte multilayers (PEMs). 

These thin films are constructed using a layer-by-layer (LbL) deposition technique. 
During LbL deposition, a suitable growth substrate (usually charged) is dipped back and forth between dilute baths of positively and negatively charged Polyelectrolyte solutions. 

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. 
Scientists have demonstrated thickness control of such films down to the single-nanometer scale. 

Polyelectrolytes can also be constructed by substituting charged species such as nanoparticles or clay platelets in place of or in addition to one of the Polyelectrolytes. 
Polyelectrolyte deposition has also been accomplished using hydrogen bonding instead of electrostatics. 

Polyelectrolytes have many applications, mostly related to modifying flow and stability properties of aqueous solutions and gels. 
For instance, they can be used to destabilize a colloidal suspension and to initiate flocculation (precipitation). 

They can also be used to impart a surface charge to neutral particles, enabling them to be dispersed in aqueous solution. 
They are thus often used as thickeners, emulsifiers, conditioners, clarifying agents, and even drag reducers. 

They are used in water treatment and for oil recovery. Many soaps, shampoos, and cosmetics incorporate Polyelectrolytes. 
Furthermore, they are added to many foods and to concrete mixtures (superplasticizer). 

Some of the Polyelectrolytes that appear on food labels are pectin, carrageenan, alginates, and carboxymethyl cellulose. 
All but the last are of natural origin. Finally, they are used in a variety of materials, including cement.

Polyelectrolytes that bear both cationic and anionic repeat groups are called polyampholytes. 
The competition between the acid-base equilibria of these groups leads to additional complications in their physical behavior. 

These polymers usually only dissolve when there is sufficient added salt, which screens the interactions between oppositely charged segments. 
In case of amphoteric macroporous hydrogels action of concentrated salt solution does not lead to dissolution of polyampholyte material due to 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. 
All proteins are polyampholytes, as some amino acids tend to be acidic, while others are basic.

Polyelectrolytes are polymers whose repeating units bear an electrolyte group. 
Polycations and polyanions are Polyelectrolytes. 

These groups dissociate in aqueous solutions (water), making the polymers charged. 
Polyelectrolyte properties are thus similar to both electrolytes (salts) and polymers (high molecular weight compounds) and are sometimes called polysalts. 

Like salts, their solutions are electrically conductive. 
Like polymers, their solutions are often viscous. 

Charged molecular chains, commonly present in soft matter systems, play a fundamental role in determining structure, stability and the interactions of various molecular assemblies. 
Theoretical approaches to describing their statistical properties differ profoundly from those of their electrically neutral counterparts, while technological and industrial fields exploit their unique properties. 

Many biological molecules are Polyelectrolytes. 
For instance, polypeptides, glycosaminoglycans, and DNA are Polyelectrolytes. 
Both natural and synthetic Polyelectrolytes are used in a variety of industries.

USAGES:

Polyelectrolytes used for flocculation in wastewater treatment systems are divided into two main groups as anionic and cationic polyelectrodes. 
Although they are nanionic polyelectrolytes they are not used much. 

In general, anionic polyelectrolytes enable the particles in waste water to be combined and precipitated in chemical treatment plants.
Polyelectrolytes are used to float flocs to be created in biological water treatment plants or to increase efficiency during dewatering of waste sludge from all treatment plants. 

Basically, there are various types of polyelectrolytes used in these principles. 
Polyelectrolyte is absolutely essential that the jar tests required for waste water systems are carried out by experts and the most appropriate use of the polyelectrolyte suitable for the system is selected. 

As a result, the treatment system can be operated healthily and efficiently.
Unlike its anionic form, Polyelectrolyte is generally used in excessively activated sludge of biological treatment plants. 

Polyelectrolyte is added to the sludge line during the pumping of the excess activated sludge taken from the sedimentation pond to filter presses or belt-presses to dewater the sludge.
Polyelectrolyte is a linear polymeric compound, because it has a variety of lively groups, affinity, adsorption and many substances forming hydrogen bonds. 
Mainly flocculation of negatively charged colloidal, turbidity, bleaching, adsorption, glue and other functions, for dyeing, paper, food, construction, metallurgy, mineral processing, coal, oil, and aquatic product processing and fermentation industries of organic colloids with higher levels of wastewater treatment, especially for urban sewage, sewage sludge, paper mill sludge and industrial sludge dewatering process.

BENEFITS:

-Improved settling rate in clarifier

-Improved efficiency of the clarifier

-Reduced retention time

-Works irrespective of ph

-Decreased Mud volumes

-Instant colour change

-Compressed filter cakes

-Effluent colour reduction

SYNONYM:

2,5-Furandione, polymer with 2-methyl-1-propene
Isobutylene/MA copolymer
26426-80-2
furan-2,5-dione;2-methylprop-1-ene
Polyelectrolyte 60
Maleic anhydride, isobutylene copolymer
maleic anhydride isobutene
Isobutylene maleic anhydride
SCHEMBL28247
DTXSID30911812
POLY(ISOBUTYLENE-ALT-MALEIC ANHYDRIDE)
Furan-2,5-dione--2-methylprop-1-ene (1/1)
2-Methyl-1-propene, polymer with 2,5-furandione
110650-69-6