Class Of Polyelectrolytes Research Articles

Interactions between an Associative Amphiphilic Block Polyelectrolyte and Surfactants in Water: Effect of Charge Type on Solution Properties and Aggregation.

The study of interactions between polyelectrolytes (PE) and surfactants is of great interest for both fundamental and applied research. These mixtures can represent, for example, models of self-assembly and molecular organization in biological systems, but they are also relevant in industrial applications. Amphiphilic block polyelectrolytes represent an interesting class of PE, but their interactions with surfactants have not been extensively explored so far, most studies being restricted to non-associating PE. In this work, interactions between an anionic amphiphilic triblock polyelectrolyte and different types of surfactants bearing respectively negative, positive and no charge, are investigated via surface tension and solution rheology measurements for the first time. It is evidenced that the surfactants have different effects on viscosity and surface tension, depending on their charge type. Micellization of the surfactant is affected by the presence of the polymer in all cases; shear viscosity of polymer solutions decreases in presence of the same charge or nonionic surfactants, while the opposite charge surfactant causes precipitation. This study highlights the importance of the charge type, and the role of the associating hydrophobic block in the PE structure, on the solution behavior of the mixtures. Moreover, a possible interaction model is proposed, based on the obtained data.

Clickable Poly(ionic liquids): A Materials Platform for Transfection

AbstractThe potential applications of cationic poly(ionic liquids) range from medicine to energy storage, and the development of efficient synthetic strategies to target innovative cationic building blocks is an important goal. A post‐polymerization click reaction is reported that provides facile access to trisaminocyclopropenium (TAC) ion‐functionalized macromolecules of various architectures, which are the first class of polyelectrolytes that bear a formal charge on carbon. Quantitative conversions of polymers comprising pendant or main‐chain secondary amines were observed for an array of TAC derivatives in three hours using near equimolar quantities of cyclopropenium chlorides. The resulting TAC polymers are biocompatible and efficient transfection agents. This robust, efficient, and orthogonal click reaction of an ionic liquid, which we term ClickabIL, allows straightforward screening of polymeric TAC derivatives. This platform provides a modular route to synthesize and study various properties of novel TAC‐based polymers.

Clickable Poly(ionic liquids): A Materials Platform for Transfection.

The potential applications of cationic poly(ionic liquids) range from medicine to energy storage, and the development of efficient synthetic strategies to target innovative cationic building blocks is an important goal. A post-polymerization click reaction is reported that provides facile access to trisaminocyclopropenium (TAC) ion-functionalized macromolecules of various architectures, which are the first class of polyelectrolytes that bear a formal charge on carbon. Quantitative conversions of polymers comprising pendant or main-chain secondary amines were observed for an array of TAC derivatives in three hours using near equimolar quantities of cyclopropenium chlorides. The resulting TAC polymers are biocompatible and efficient transfection agents. This robust, efficient, and orthogonal click reaction of an ionic liquid, which we term ClickabIL, allows straightforward screening of polymeric TAC derivatives. This platform provides a modular route to synthesize and study various properties of novel TAC-based polymers.

Single-Ion Block and Random Copoly(ionic liquid)s As Innovative Electrolytes for All-Solid State Li Batteries

In recent years, wide research efforts have been devoted to the development of solid polymer electrolytes (SPEs) with the goal to enhance the intrinsic safety and replace the traditional flammable liquid electrolytes employed in the lithium-ion battery technology (LIBs). Among SPEs, a new class of polyelectrolytes, namely poly(ionic liquid)s (PILs) has deserved considerable attention. Although significant progress has already been achieved with cationic PILs/Li salt composites, the power delivery of such electrolytes is hampered by the strong concentration gradients formed during battery operation. As an alternative the anionic polyelectrolytes or so called “polymeric single-ion conductors” have been recently suggested. In this work, we present two approaches for the preparation of the innovative families of single-ion polymer electrolytes. First approach consists in the synthesis of ionic block copolymers via RAFT polymerization technique. Such copolymers comprise poly(lithium 1-[3-(methacryloyloxy)propylsulfonyl]-1-(trifluoromethylsulfonyl)imide) and poly(ethylene glycol) methyl ether methacrylate blocks (Fig. 1A). This method allowed to vary the molecular weight of PILs and to gain the desired control over polymer’s T g and ionic conductivity. The “best” obtained polyelectrolyte with Mn = 2.5x104 g/mol shows the T g as low as -61 ºC, ionic conductivity as high as 2.3×10-6 and 1.2×10-5 S cm-1 at 25 and 60o C, respectively, wide electrochemical stability (4.5 V vs Li+/Li) and a lithium-ion transference number close to unity (0.83).Second utilized approach involves the free radical copolymerization of ionic liquid like monomers with poly(ethylene glycol) methyl ether methacrylate for the preparation of random ionic copolymers. Here, polymer’s ionic conductivity and T g were controlled by the nature of ionic monomer and the molar composition of statistic copolymer (Fig. 1B). The “optimal” coPIL with Mw = 4.2x105 g/mol demonstrates T g = -56 ºC, ionic conductivity equal to 1.8×10-6 and 1.5×10-5 S cm-1 at 25 and 60o C, respectively, wide electrochemical stability (4.2 V vs Li+/Li) and high lithium-ion transference number (0.91). Owing to the combination of all mentioned properties, the prepared polymer materials were used as solid polyelectrolytes as well as binders in the elaboration of truly solid Li/coPIL/LiFePO4 battery prototypes working at 60-70oC and delivering large capacities (up to 130 mAh/g), with an impressive charge/discharge efficiency and the capability to reversibly operate at relatively high rates up to C/5 (Fig. 1C). This work was supported by the Russian Foundation for Basic Research (projects no. 14-29-04039_ofi_m and 16-03-00768_a) and by European Commission (project no. 318873 «IONRUN»). J.R.N. gratefully acknowledges financial support from MARS-EV project (FP7/2007-2013, under grant agreement n° 609201). Figure 1

Poly(ionic liquid)s: Synthesis, properties, and application

The overview of the published data on a new class of polyelectrolytes—the so-called polymeric ionic liquids or poly(ionic liquid)s—is presented. The peculiarities of their synthesis and the factors affecting their molar masses, solubility, ionic conductivity, electrochemical stability, and thermal properties are discussed. The mainstreams in the application of poly(ionic liquid)s and materials formed on their basis are illustrated by specific examples.

Nanocomposites Based on Luminescent Colloidal Nanocrystals and Polymeric Ionic Liquids towards Optoelectronic Applications.

Polymeric ionic liquids (PILs) are an interesting class of polyelectrolytes, merging peculiar physical-chemical features of ionic liquids with the flexibility, mechanical stability and processability typical of polymers. The combination of PILs with colloidal semiconducting nanocrystals leads to novel nanocomposite materials with high potential for batteries and solar cells. We report the synthesis and properties of a hybrid nanocomposite made of colloidal luminescent CdSe nanocrystals incorporated in a novel ex situ synthesized imidazolium-based PIL, namely, either a poly(N-vinyl-3-butylimidazolium hexafluorophosphate) or a homologous PIL functionalized with a thiol end-group exhibiting a chemical affinity with the nanocrystal surface. A capping exchange procedure has been implemented for replacing the pristine organic capping molecules of the colloidal CdSe nanocrystals with inorganic chalcogenide ions, aiming to disperse the nano-objects in the PILs, by using a common polar solvent. The as-prepared nanocomposites have been studied by TEM investigation, UV-Vis, steady-state and time resolved photoluminescence spectroscopy for elucidating the effects of the PIL functionalization on the morphological and optical properties of the nanocomposites.

Zwitterionic Polyelectrolytes: A Review

AbstractRecent progress in the field of zwitterionic polyelectrolytes is reviewed. This class of polyelectrolytes is only five decades old, since the first synthesis was in 1952. Polycarboxybetaines, polysulfobetaines, polyphosphobetaines and a few more zwitterionic materials compose this class of polymers. In the current search for ‘biomimicking’ materials, this class is particularly important. The responsive properties of polyzwitterions are specific, sensitive and instantaneous to a wide variety of external stimuli, which has been reviewed in this article. The synthesis of polyampholytes and polybetaines (homopolymers, copolymers, block polymers) are reviewed. The exploitation of such materials in solid state conducting materials, chromatographic materials and other applications has been incorporated. The extensive discussion on solution properties, antipolyelectrolytic characteristics and influence of varying class of electrolytes has been qualitative as well as quantitative providing an insight into the importance and relevance of such materials, the block polymers form reversible ‘schizophrenic’ micelles also.

Transport properties of some cationic polysaccharides: 2. Charge density effect

The charge density effect on the behavior of some cationic polysaccharides in aqueous and nonaqueous (methanol) solutions was studied by viscometric and conductometric measurements. The polyelectrolytes investigated contain quaternary ammonium salt groups, N-alkyl- N , N -dimethyl-2-hydroxypropylene ammonium chloride, attached to a dextran backbone. This new class of polyelectrolytes has various linear charge density parameters, ξ, located below and above the critical threshold value of counterions condensation, ξ c = 1 ( ξ = 0.25 – 3.18 ) . The viscometric data revealed that all copolymers exhibit a polyelectrolyte behavior and were plotted in the terms of Rao equation. The conductometric measurements of solutions of these copolymers were presented as a function of polymer concentration and charge density. The results were analyzed within the Manning's theory and lower experimental values of the equivalent conductivity than the theoretical ones were found. Possible reasons of this discrepancy have been discussed. The interaction parameters were evaluated and these were found to depend on both the polymer concentration and the charge density. The conductometric behavior of these cationic polysaccharides has shown that counterion condensation is not a threshold phenomenon, their association to the charged groups of the polyions taking place for ξ > 1 as well as ξ < 1 .

Synthesis and photochemical reaction of polyarylenesulfonium salts

A novel class of polyelectrolytes having triphenylsulfonio groups in its main chain was synthesized by the sulfoxide-acid system reaction from the corresponding aryl sulfoxide monomers. The photo-irradiation of ultraviolet light at the π-π * transition band resulted in the selective degradation of the polymer to the corresponding aryl or alkyl sulfide monomer. The photodegradation is accompanied by proton generation, which could be useful for the photoinitiated polymerization of epoxy compounds. The differences between the monomeric and the polymeric sulfonium salts in their photodegradation properties were examined on the basis of kinetics of photodegradation, quantum yields and the conversion in the photoinitiated polymerization of the epoxy monomer. The polymeric sulfonium salts are more effective than the monomeric ones due to larger e (extinction coefficient) at the irradiation wavelength.

A new class of complex water-soluble polyelectrolytes

Water-soluble nonstoichiometric polyelectrolyte complexes (N-PEC) constitute a new class of polyelectrolytes. N-PEC are formed as a result of interaction between oppositely charged polyelectrolytes taken in non-equivalent rations and thus they are macromolecular compounds. An N-PEC particle can be represented as a macromolecule of a segmented block copolymer. The behaviour of the N-PEC in aqueous-salt media shows their polyelectrolyte nature, but in contrast to ordinary polyelectrolytes, they undergo considerable conformational changes. These transitions precede phase separations, which are unique and are accompanied by the phenomena of disproportionation. Using N-PEC as enzyme carriers it is possible to produce self-regulating systems with a feedback and also thermostable systems, which are the simplest models of a spore. The N-PEC formed by synthetic polyelectrolytes and some proteins, show a pronounced physiological activity and belong to the class of highly immunogenic antigens.

A New Approach to Permeability Reduction

Introduction There are many published schemes for reducing the permeability of reservoir rock. The method described here permeability of reservoir rock. The method described here involves plugging interpore connections with colloidal particles. The novelty of this method is the chemistry of particles. The novelty of this method is the chemistry of the process, which enables one to pump a homogeneous solution into the reservoir before the formation of colloidal particles. The chemical basis of this process revolves around the reactions of a new class of polyelectrolytes, polyisocyanurate salt (TmPI). When 2,4-tolylene polyisocyanurate salt (TmPI). When 2,4-tolylene diisocyanate reacts with alkali metal cyanates in dipoler, aprotic solvents and the final reaction mixture is treated with methanol, a polyisocyanurate salt, TmPI (T for tolylene based, M for methanol blocked, and PI for polyisocyanurate salt), forms. polyisocyanurate salt), forms. These polyisocyanurate salts are soluble in water or in basic solution. As the pH is lowered approaching the acid region, the anionic groups are protonated, and the resulting polyisocyanuric acid precipitates from solution. Neutral or slightly basic solutions are stable for long periods of time, giving solutions with essentially the periods of time, giving solutions with essentially the viscosity of water for moderate concentrations of TmPI (less than 20 percent w/w). The reaction of TmPI used in this work is the hydrolysis reaction occurring in strongly basic solutions. In basic solution, the isocyanurate salt group is subjected to nucleophilic attack by the hydroxide ion at a position para to the charged site. The end product of the hydrolysis reaction (TMPI-B) is a complex molecule containing both salt groups and bioret groups from the hydrolysis of the isocyanurate rings. The hydrolysis reaction ceases before completion, when the number of hydrophobic bioret groups per molecule has increased sufficiently to render the molecule insoluble. The reaction is irreversible. This polymeric precipitate, TmPI-B, forms a colloidal suspension polymeric precipitate, TmPI-B, forms a colloidal suspension defying filtration. This nonfilterability suggested using in-situ hydrolysis of TmPI as the basis for a partial plugging process. plugging process. The process begins with injection of a basic, aqueous solution of a polyisocyanurate salt into a porous medium. After injection, the solution is allowed to reside in the medium until the hydrolysis reaction ceases. At this point, the TmPI-B product has precipitated uniformly throughout the porous medium. Thus, this reaction gives the capability of porous medium. Thus, this reaction gives the capability of generating particles within the pores of the medium. Subsequent flow traps these particles within the interpore flow channels, causing reduction of permeability. Experimental Evaluation Plugging agents were evaluated with a series of Plugging agents were evaluated with a series of coreflooding experiments. A porous medium was saturated with water containing 1.8 percent by-weight sodium chloride. The flooding sequence was initiated by injecting brine water until steady-state flow permitted measurement of the initial permeability of the medium. Once satisfactory values were obtained, an aqueous solution of the plugging agent was injected. The volume of solution plugging agent was injected. The volume of solution injected at this point was sufficient to ensure complete saturation of the porous medium. When the desired amount of plugging solution was injected, flow was stopped. JPT P. 592