Abstract: Polyelectrolyte complexes are omnipresent both in nature and in the technological world, including nucleotide condensates, biological marine adhesives, food stabilizers, encapsulants, and carriers for gene therapy. However, the true phase behavior of complexes, resulting from associative phase separation of oppositely charged polyelectrolytes, remains poorly understood. Here, we rely on complementary experimental and simulation approaches to create a complete quantitative description of the phase behavior of polyelectrolyte complexes that represents a significant advance in our understanding of the underlying physics of polyelectrolyte complexation. Experiments employing multiple approaches with model polyelectrolytes—oppositely charged polypeptides poly(l-lysine) and poly(d,l-glutamic acid) of matched chain lengths—led to phase diagrams with compositions of the complex and the supernatant that were in excellent agreement with simulation results. Contrary to the widely accepted theory for complexation, we...

Abstract: Covalent organic frameworks (COFs) with ordered one-dimensional channels could offer a predesigned pathway for ion motion. However, implanting salts into bare channels of COFs gives rise to a limited ion conductivity. Here, we report the first example of polyelectrolyte COFs by integrating flexible oligo(ethylene oxide) chains onto the pore walls. Upon complexation with lithium ions, the oligo(ethylene oxide) chains form a polyelectrolyte interface in the nanochannels and offer a pathway for lithium ion transport. As a result, the ion conductivity was enhanced by more than 3 orders of magnitude compared to that of ions across the bare nanochannels. The polyelectrolyte COFs promoted ion motion via a vehicle mechanism and exhibited enhanced cycle and thermal stabilities. These results suggest that the strategy for engineering a polyelectrolyte interface in the 1D nanochannels of COFs could open a new way to solid-state ion conductors.

Abstract: Polyelectrolytes have many important functions in both living organisms and man-made applications One key property of polyelectrolytes is the ionic conductivity due to their porous networks that allow the transport of water and small molecular solutes Among polyelectrolytes, zwitterionic polymers have attracted huge attention for applications that involve ion transport in a polyelectrolyte matrix; however, it is still unclear how the functional groups of zwitterionic polymer side chains affect their ion transport and swelling properties In this study, zwitterionic poly(carboxybetaine acrylamide), poly(2-methacryloyloxyethyl phosphorylcholine), and poly(sulfobetaine methacrylate) hydrogels were synthesized and their ionic conductivity was studied and compared to cationic, anionic, and nonionic hydrogels The change of the ionic conductivity of zwitterionic and nonionic hydrogels in different saline solutions was investigated in detail Zwitterionic hydrogels showed much higher ionic conductivity than that of the widely used nonionic poly(ethylene glycol) methyl ether methacrylate hydrogel in all tested solutions For both cationic and anionic hydrogels, the presence of mobile counterions led to high ionic conductivity in low salt solutions; however, the ionic conductivity of zwitterionic hydrogels surpassed that of cationic and ionic hydrogels in high salt solutions Cationic and anionic hydrogels showed much higher water content than that of zwitterionic hydrogels in deionized water; however, the cationic hydrogels shrank significantly with increasing saline concentration This work provides insight into the effects of polyelectrolyte side chains on ion transport This can guide us in choosing better polyelectrolytes for a broad spectrum of applications, including bioelectronics, neural implants, battery, and so on

Abstract: Chemically inert, mechanically tough, cationic metallo-polyelectrolytes were conceptualized and designed as durable anion-exchange membranes (AEMs). Ring-opening metathesis polymerization (ROMP) of cobaltocenium-containing cyclooctene with triazole as the only linker group, followed by backbone hydrogenation, led to a new class of AEMs with a polyethylene-like framework and alkaline-stable cobaltocenium cation for ion transport. These AEMs exhibited excellent thermal, chemical and mechanical stability, as well as high ion conductivity.

Abstract: Throughout the last decades, magnetic nanoparticles (MNP) have gained tremendous interest in different fields of applications like biomedicine (eg, magnetic resonance imaging (MRI), drug delivery, hyperthermia), but also more technical applications (eg, catalysis, waste water treatment) have been pursued Different surfactants and polymers are extensively used for surface coating of MNP to passivate the surface and avoid or decrease agglomeration, decrease or modulate biomolecule absorption, and in most cases increase dispersion stability For this purpose, electrostatic or steric repulsion can be exploited and, in that regard, surface charge is the most important (hybrid) particle property Therefore, polyelectrolytes are of great interest for nanoparticle coating, as they are able to stabilize the particles in dispersion by electrostatic repulsion due to their high charge densities In this review article, we focus on polyzwitterions as a subclass of polyelectrolytes and their use as coating materials for MNP In the context of biomedical applications, polyzwitterions are widely used as they exhibit antifouling properties and thus can lead to minimized protein adsorption and also long circulation times

Abstract: The study of proton conductivity processes has gained intensive attention in the past decades due to their potential applications in chemical sensors, electrochemical devices, and energy generation. The scientific community has focused its efforts on the development of high‐performing polymeric membranes as proton exchange membranes (PEMs) for fuel cell (FC) applications. In particular, high conductivity at different humidity and temperature and enhanced chemical and mechanical stability under operative conditions are considered the main goals to be reached. The design of mixed‐matrix membranes (MMMs) based on conductive polymers and inorganic fillers is an approach commonly used for achieving materials with improved conductive and mechanical properties. In the last five years, the use of metal‐organic frameworks (MOFs) as fillers for conductive MMMs has rapidly grown for their intrinsic stability and structural versatility. The recent progress around the proton conductivity of MOF based composite membranes on PEMs for FC applications is critically reviewed.

Abstract: Polyelectrolytes are an important class of polymeric materials and are increasingly used in complex industrial formulations. A core use of these materials is in mixtures with surfactants, where a combination of hydrophobic and electrostatic interactions drives unique solution behavior and structure formation. In this review, we apply a molecular level perspective to the broad literature on polyelectrolyte-surfactant complexes, discussing explicitly the hydrophobic and electrostatic interaction contributions to polyelectrolyte surfactant complexes (PESCs), as well as the interplay between the two molecular interaction types. These interactions are sensitive to a variety of solution conditions, such as pH, ionic strength, mixing procedure, charge density, etc. and these parameters can readily be used to control the concentration at which structures form as well as the type of structure in the bulk solution.

Abstract: The past decade has witnessed rapid advances in porous polyelectrolytes and there is tremendous ongoing interest in their synthesis and applications in environment, energy, biomedicine and catalysis. The porous polyelectrolytes research is motivated by the synergy of, apart from the flexible choice of functional organic groups and processing technologies, the charge and pores spanning length scales from individual polyelectrolyte backbones to their nano/micro superstructures. This review surveys recent progresses on porous polyelectrolytes including membranes, particles, scaffolds, high surface area powders/resins, and their derivatives. Our focus is the interplay between surface chemistry, Columbic interaction and poreconfinement that defines new chemistry and physics in such materials for implications including energy conversion, molecular separation, water purification, sensing/actuation, catalysis, tissue engineering, and nanomedicine.

Abstract: In response to prepare high-stable and ion-conducting polyelectrolyte for hydroxide exchange membrane (HEM) applications, we present an ultrastable polyelectrolyte based on six-membered heterocyclic 6-azonia-spiro[5.5]undecane (ASU) and polyphenyl ether (PPO). A series of ASU-functionalized PPO polyelectrolytes (ASU–PPO), which can be easily dissolved in low-boiling pointing solvent, have been successfully synthesized by a remote-grafting method. The ASU precursor is stable in 1 M NaOH/D2O at 80 °C for 2500 h as well as in 5 M NaOH/D2O at 80 °C for 2000 h, and the predicted half-life of the ASU precursor would exceed 10 000 h, even higher in the future. Besides, these remote-grafting ASU–PPO polyelectrolytes are stable in 1 M NaOH(aq) at 80 °C for 1500 h. Robust and pellucid segmented ASU and triple-ammonium-functionalized PPO-based HEMs attach OH– conductivity of 96 mS/cm at 80 °C and realize maximal power density of 178 mW/cm2 under current density of 401 mA/cm2.

Abstract: Water plays a central role in the assembly and the dynamics of charged systems such as proteins, enzymes, DNA, and surfactants. Yet it remains a challenge to resolve how water affects relaxation at a molecular level, particularly for assemblies of oppositely charged macromolecules. Here, the molecular origin of water’s influence on the glass transition is quantified for several charged macromolecular systems. It is revealed that the glass transition temperature (Tg) is controlled by the number of water molecules surrounding an oppositely charged polyelectrolyte–polyelectrolyte intrinsic ion pair as 1/Tg ∼ ln(nH2O/nintrinsic ion pair). This relationship is found to be “general”, as it holds for two completely different types of charged systems (pH- and salt-sensitive) and for both polyelectrolyte complexes and polyelectrolyte multilayers, which are made by different paths. This suggests that water facilitates the relaxation of charged assemblies by reducing attractions between oppositely charged intrinsic ...

Abstract: Polyelectrolytes may be classified into two primary categories (strong and weak) depending on how their charge state responds to the local environment. Both of these find use in many applications, ...

Abstract: Solvent-free single-ion polymer electrolytes with high conductivity have historically been prepared in the form of block copolymer or polymer blends. In this work, single-ion homopolymer electrolytes consisting of poly(poly(ethylene oxide) methacrylate lithium sulfonyl(trifluoromethylsulfonyl)imide), poly(PEOMA-TFSI-Li+), were prepared for the first time by photoinduced metal-free atom-transfer radical polymerization (ATRP). The PEO-based macromonomer PEOMA-TFSI-Li+ was synthesized via click chemistry - copper-catalyzed alkyne-azide cycloaddition (CuAAC). Due to the conductive, amorphous PEO phase in which the lithium ions are located, these polymers showed improved ionic conductivity (10-5 ~ 10-4 S/cm at 90 oC) and high transference number (0.97 ~0.99). The potential dendrite suppressing capability of the polyelectrolytes was estimated by employing a kinetic model using the measured transport and transference properties to study the current density at the dendrite tip. The analysis indicates that the syn...

Abstract: The rheology of water-soluble polyelectrolytes at intermediate and high concentrations is controlled by entanglement, hydrophobic, and electrostatic interactions, whose influences are difficult to isolate. We investigate the rheology of semidilute solutions of sodium carboxymethyl cellulose (NaCMC) with molecular weight Mw ≃ 2.5 × 105 g/mol and varying degree of substitution (DS) as a function of polymer concentration in various solvent media: salt-free water (long-ranged electrostatic interactions), 0.5 M aqueous NaCl (screened electrostatics), and 0.5 M aqueous NaOH (screened electrostatics, diminished hydrophobic interactions) in order to selectively examine the role played by these different interactions. Decreasing DS is found to decrease solubility and induce partial aggregation and eventual gelation. In salt-free and 0.5 M NaCl solution, NaCMC with DS ≃ 1.2 exhibits hydrophilic polyelectrolyte and neutral polymer in good solvent behavior, respectively. Decreasing DS to ≃0.7–0.8 leads to hydrophobic...

Abstract: Some polyzwitterionic brushes exhibit a strong “anti-polyelectrolyte effect” and ionic specificity that make them versatile platforms to build smart surfaces for many applications. However, the structure–property relationship of zwitterionic polymer brushes still remains to be elucidated. Herein, we aim to study the structure-dependent relationship between different zwitterionic polymers and the anti-polyelectrolyte effect. To this end, a series of polyzwitterionic brushes with different cationic moieties (e.g., imidazolium, ammonium, and pyridinium) in their monomeric units and with different carbon spacer lengths (e.g., CSL = 1, 3, and 4) between the cation and anion were designed and synthesized to form polymer brushes via the surface-initiated atom transfer radical polymerization. All zwitterionic brushes were carefully characterized for their surface morphologies, compositions, wettability, and film thicknesses by atomic force microscopy, contact angle measurement, and ellipsometry, respectively. The...

Abstract: Superabsorbent polymers are widely used in many applications such as disposable diapers, feminine napkins, soil for agriculture and horticulture, gel actuators, water-blocking tapes, drug delivery systems, absorbent pads and other biomedical applications. Most of these superabsorbents are non-biodegradable and thus increasing burden on the earth. Polymer scientist and chemists are looking for environmental friendly solutions. Polyaspartic acid polymers have been reported to possess biodegradable properties. These polymers have been developed mainly as polyelectrolyte. However, this review compiles the work carried on developing polyaspartic acid based superabsorbent polymers. The review covers synthetic methodology, characterization of these polymers by different techniques, different types of polymer prepared using polyaspartic polymers which include co-polymers, grafted polymers, interpenetrating and semi-interpenetrating polymers are covered. The biodegradability studies carried out on the superabsorbent polymers are also discussed.

Abstract: Foreign-body reaction (FBR) has been a long-term obstacle for implantable biomedical devices and materials, especially to those that require mass/signal transport between the implants and the body. However, currently, very limited biomaterials can mitigate FBR. In this work, we develop a balanced charged polyelectrolyte hydrogel that can efficiently resist FBR and collagenous capsule formation in a mouse model. Using this new strategy, we can easily tune the antifouling properties of the polyelectrolyte hydrogels by changing the ratio of negatively charged alginate and positively charged poly(ethylene imine). We find that at the optimum ratio where the net charge of hydrogel is neutral, the adhesion of proteins, cells, bacteria, and fresh blood on its surface can be significantly inhibited, indicating its excellent antifouling properties. In vivo studies show that after being implanted subcutaneously, this balanced charged hydrogel can prevent the capsule formation for at least 3 months. Furthermore, immu...

Abstract: We develop a scaling theory and perform molecular dynamic simulations of weakly interacting coacervates with electrostatic interaction energy per charge less than thermal energy kT. Such liquid coacervates formed by oppositely charged polyelectrolytes can be asymmetric in charge density and number of charges per chain. We predict that these coacervates form interpenetrating solutions with two correlation lengths and two qualitatively different types of conformations of polyelectrolytes with lower and higher charge densities, which are analogous to chain conformations in quasi-neutral and in polyelectrolyte solutions, respectively. Weaker charged chains are attracted to and adsorbed on stronger charged chains forming a screening "coat" around the stronger charged polyelectrolytes. Salt added at lower concentrations screens the repulsion between stronger charged chains, thereby reducing the thickness of the screening coat and resulting in the non-zero net polymer charge in the coacervate. At higher salt concentrations salt screens the attraction between oppositely charged chains, decreasing the coacervate concentration and its polymeric charge density. Thus, we predict a non-monotonic salt concentration dependence of polymeric charge density for asymmetric coacervates. Phase diagram for a mixture of oppositely charged polyelectrolytes at various compositions is proposed for different salt concentrations.

Abstract: Polyelectrolyte complex micelles (PCMs), nanoparticles formed by electrostatic self-assembly of charged polymers with charged-neutral hydrophilic block copolymers, offer a potential solution to the challenging problem of delivering therapeutic nucleic acids into cells and organisms. Promising results have been reported in vitro and in animal models but basic structure–property relationships are largely lacking, and some reports have suggested that double-stranded nucleic acids cannot form PCMs due to their high bending rigidity. This letter reports a study of PCMs formed by DNA oligonucleotides of varied length and hybridization state and poly(l)lysine-poly(ethylene glycol) block copolymers with varying block lengths. We employ a multimodal characterization strategy combining small-angle X-ray scattering (SAXS), multiangle light scattering (MALS), and cryo-electron microscopy (cryo-TEM) to simultaneously probe the morphology and internal structure of the micelles. Over a wide range of parameters, we find ...

Abstract: With the boom of flexible electronic products and wearable devices, flexible energy storage devices, for example, supercapacitors with high performance, are attracting increasing interest. A flexible water-deactivated polyelectrolyte hydrogel electrolyte with good mechanical properties and high ionic conductivity was prepared by using an anionic polymer, carboxy methyl cellulose, and a cationic monomer, methacrylamidopropyltrimethyl ammonium chloride. It was then applied in a supercapacitor with flexible activated carbon electrodes. This flexible supercapacitor possesses a high operating voltage of 2.1 V owing to the low electrochemical activity for water within the hydrogel as a result of the 'molecular cages' effect and hydrophilic interactions between functional groups and surrounding water molecules. Furthermore, this supercapacitor exhibits good flexibility and tailorability. As the first example of water-deactivated polyelectrolyte hydrogel electrolytes in applications involving flexible high-voltage supercapacitors, this work provides a platform for the design of energy storage devices with high energy density for flexible and wearable electronic devices.