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Polyelectrolytes are used in different technology systems, such as reducing environmental pollution, producing lithium batteries, achieving better performance, and prolonging half-life. One of the vital applications of polyelectrolytes is in drug delivery systems as a drug carrier to reach the specific desired target organ and increase drug effectiveness. To find and reach the optimum complex of polyelectrolytes in the context of drug delivery systems, we used Luminescence spectroscopy, viscosimetry, and conductivity methods in different concentrations, pH, and temperatures to find the polyelectrolyte's behavior in cationic and anionic polymers besides copolymers. In this study, Polyallylamine P(AlAm), polyallylamine hydrochloride P(AlAm.HCl), polyvinyl sulfonic acid P(VSA), and copolymer (32:68) actual composition are investigated. The hydrophobicity of the polymer is prominent at higher pH with P(AlAm.HCl). A more hydrophilic polymer is produced by forming the NH3+ ions at lower pH. P(AlAm) hydrophobicity is determined at higher pH, and hydrophilicity happens at low pH. The temperature has now not affected the polymer's hydrophilicity and hydrophobicity. Increasing and lowering pH from 4.5 has not revealed a substantial P(VSA) change. The temperature and pH no longer affect the copolymer. We prepared complex formation of P(AlAm.HCl), P(AlAm), P(VSA), and copolymer with anionic surfactant sodium dodecylbenzene sulfonate (SDBS) in under and above critical micelle concentration (CMC) value. Excellent complexation is obtained among P(AlAm.HCl) and SDBS using Luminescence spectroscopy. Moreover, the viscosity behavior of P(AlAm.HCl) and P(AlAm) in pure water and 0.5 M NaCl solution is investigated. The polyelectrolyte properties of P(AlAm.HCl) are lots better than P(AlAm). That is confirmed using the Luminescence and conductivity method in different pH values. [ABSTRACT FROM AUTHOR]

Biomaterials such as spider silk and mussel byssi are fabricated by the dynamic manipulation of intra‐ and intermolecular biopolymer interactions. Organisms modulate solution parameters, such as pH and ion co‐solute concentration, to effect these processes. These biofabrication schemes provide a conceptual framework to develop new dynamic and responsive abiotic soft material systems. Towards these ends, the chemical diversity of readily available ionic compounds offers a broad palette to manipulate the physicochemical properties of polyelectrolytes via ion‐specific interactions. In this study, we show for the first time that the ion‐specific interactions of biomimetic polyelectrolytes engenders a variety of phase separation behaviors, creating dynamic thermal‐ and ion‐responsive soft matter that exhibits a spectrum of physical properties, spanning viscous fluids to viscoelastic and viscoplastic solids. These ion‐dependent characteristics are further rendered general by the merger of lysine and phenylalanine into a single, amphiphilic vinyl monomer. The unprecedented breadth, precision, and dynamicity in the reported ion‐dependent phase behaviors thus introduce a broad array of opportunities for the future development of responsive soft matter; properties that are poised to drive developments in critical areas such as chemical sensing, soft robotics, and additive manufacturing. [ABSTRACT FROM AUTHOR]

Developing a straightforward strategy for constructing highly processable photonic crystals (PCs) is crucial for various applications, yet remains a challenge. Here, we present a simple polyelectrolyte-induced self-assembly strategy for producing novel photonic crystal (PC) inks with outstanding processing flexibility by adding the polyelectrolytes into the ultralow concentration of colloidal nanoparticle solution. The polyelectrolyte can cover the nanoparticles through the hydrogen bond interaction to induce the aggregation and mutual repulsion of them simultaneously, enabling the self-assembly of ultralow concentration (0.01–1.0 v/v%) of nanoparticles into short-range ordered arrays with angle-independent structural colors. The resulting PC inks present unprecedented pigment-like color modulation capacity, as well as ultrahigh freedom in processing methods due to the fact that the rheological behaviors of PC inks can be widely adjusted by varying the properties of polyelectrolytes. Consequently, the PC inks can be easily shaped into complex and exquisite multicolor patterns/3D structures using various techniques, including injection molding, writing, drawing, and 3D printing. This general approach paves the way for quick and scalable production of advanced PC materials deeply required in practical applications. [ABSTRACT FROM AUTHOR]

Hydrogel actuators with complex 3D initial shapes show numerous important applications, but it remains challenging to fabricate such actuators. This article describes a polyelectrolyte‐based strategy for modulating small‐scale internal stresses within hydrogels to construct complex actuators with tailored 3D initial shapes. Introducing polyelectrolytes into precursor solutions significantly enhances the volume shrinkage of hydrogel networks during polymerization, allowing us to modulate internal stresses. Photopolymerization of these polyelectrolyte‐containing solutions through a mask produces mechanically strong hydrogel sheets with large patterned internal stresses. Consequently, these hydrogel sheets attain complex 3D initial shapes at equilibrium, in contrast to the planar initial configuration of 2D actuators. We demonstrate that these 3D actuators can reversibly transform into other 3D shapes (i.e. 3D‐to‐3D shape transformations) in response to external stimuli. Additionally, we develop a predictive model based on the Flory‐Rehner theory to analyze the polyelectrolyte‐mediated shrinking behaviors of hydrogel networks during polymerization, allowing precise modulation of shrinkage and internal stress. This polyelectrolyte‐boosted shrinking mechanism paves a route to the fabrication of high‐performance 3D hydrogel actuators. [ABSTRACT FROM AUTHOR]

The present study deals with the assessment of different physicochemical parameters (pH, electrical conductivity (E.C.), turbidity, total dissolved solids (TDS), and dissolved oxygen) in different surface water such as pond, river, and canal water in four different seasons, viz. March, June, September, and December 2023. The research endeavors to assess the impact of a cationic polyelectrolyte, specifically poly(diallyl dimethyl ammonium chloride) (PDADMAC), utilized as a coagulation aid in conjunction with lime for water treatment. Employing a conventional jar test apparatus, turbidity removal from diverse water samples is examined. Furthermore, the samples undergo characterization utilizing X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The study also conducts correlation analyses on various parameters such as electrical conductivity (EC), pH, total dissolved solids (TDS), turbidity of raw water, polyelectrolyte dosage, and percentage of turbidity removal across different water sources. Utilizing the Statistical Package for Social Science (SPSS) software, these analyses aim to establish robust relationships among initial turbidity, temperature, percentage of turbidity removal, dosage of coagulant aid, electrical conductivity, and total dissolved solids (TDS) in pond water, river water, and canal water. A strong positive correlation could be found between the percentage of turbidity removal and the value of initial turbidity of all surface water. However, a negative correlation could be observed between the polyelectrolyte dosage and raw water's turbidity. By elucidating these correlations, the study contributes to a deeper understanding of the effectiveness of PDADMAC and lime in water treatment processes across diverse environmental conditions. This research enhances our comprehension of surface water treatment methodologies and provides valuable insights for optimizing water treatment strategies to address the challenges posed by varying water sources and seasonal fluctuations. [ABSTRACT FROM AUTHOR]

This review comprehensively explores the multifunctional applications of pectins derived from food waste and by-products, emphasizing their role as versatile biomaterials in the medical-related sectors. Pectins, known for their polyelectrolytic nature and ability to form hydrogels, influence the chemical composition, sensory properties, and overall acceptability of food and pharmaceutical products. The study presents an in-depth analysis of molecular parameters and structural features of pectins, such as the degree of esterification (DE), monosaccharide composition, galacturonic acid (GalA) content, and relative amounts of homogalacturonan (HG) and rhamnogalacturonan I (RG-I), which are critical for their technofunctional properties and biological activity. Emphasis is placed on pectins obtained from various waste sources, including fruits, vegetables, herbs, and nuts. The review also highlights the importance of structure–function relationships, especially with respect to the interfacial properties and rheological behavior of pectin solutions and gels. Biological applications, including antioxidant, immunomodulatory, anticancer, and antimicrobial activities, are also discussed, positioning pectins as promising biomaterials for various functional and therapeutic applications. Recalled pectins can also support the growth of probiotic bacteria, thus increasing the health benefits of the final product. This detailed review highlights the potential of using pectins from food waste to develop advanced and sustainable biopolymer-based products. [ABSTRACT FROM AUTHOR]

The investigation of the interplay between complex coacervate microdroplets and amphiphilic molecules offers valuable insights into the processes of prebiotic compartmentalization on the early Earth and presents a promising avenue for future advancements in biotechnology. Herein, the interaction between complex coacervate microdroplets and amphiphilic molecule (decanoic acid) is systematically investigated by varying charge strengths of negatively charged polyelectrolytes (DNA and PAA) and positively charged polyelectrolytes (PDDA and DEAE‐Dextran). It is found that the interaction between amphiphilic molecule and complex coacervate microdroplets depended on the delicate balance between the interaction between decanoic acid and polyelectrolyte and the interaction between two polyelectrolytes. The different spatial distribution of amphiphilic molecule can result in differences in the internal microenvironment, which can further alter the uptake or exclusion of small molecules and biomolecules with different charges and polarities and functional biological process. [ABSTRACT FROM AUTHOR]

Acidic CO2 electrolysis offers a promising strategy to achieve high carbon utilization and high energy efficiency. However, challenges still remain in suppressing the competitive hydrogen evolution reaction (HER) and improving product selectivity. Although high concentrations of potassium ions (K+) can suppress HER and accelerate CO2 reduction, they still inevitably suffer from salt precipitation problems. In this study, we demonstrate that the sulfonate‐based polyelectrolyte, polystyrene sulfonate (PSS), enables to reconstruct the electrode‐electrolyte interface to significantly enhance the acidic CO2 electrolysis. Mechanistic studies reveal that PSS induces high local K+ concentrations through the electrostatic interaction between PSS anions and K+. In situ spectroscopy reveals that PSS reshapes the interfacial hydrogen–bond (H‐bond) network, which is attributed to the H‐bonds between PSS anions and hydrated proton, as well as the steric hindrance of the additive molecules. This greatly weakens proton transfer kinetics and leads to the suppression of undesirable HER. As a result, a Faradaic efficiency of 93.9 % for CO can be achieved at 250 mA cm−2, simultaneous with a high single‐pass carbon efficiency of 72.2 % on commercial Ag catalysts in acid. This study highlights the important role of the electrode‐electrolyte interface induced by polyelectrolyte additives in promoting electrocatalytic reactions. [ABSTRACT FROM AUTHOR]

We present the results of molecular dynamics simulations of steady shear between a pair of neutral polymer brushes, as well as a pair of charged polymer brushes in the strongly compressed regime. The results of the molecular dynamic simulations of neutral and polyelectrolyte brushes in implicit solvent including normal forces, shear forces, viscosities and friction coefficients as a function of separation between brushes, are presented in the study. The comparison of the simulation results of neutral and charged brushes shows that the charged brushes is in the quasi-neutral regime, and the dependence of viscosity on the separation distance show the similar power law of neutral brushes. Our simulation results confirm that the implicit solvent simulations of polyelectrolyte brushes that ignore hydrodynamics interaction are in agreement with the scaling predictions qualitatively because of screening of hydrodynamic interaction and long-range electrostatic interactions on the correlation length scale. Both of neutral and charged brushes show the lubrication properties that the friction coefficient decreases with the separation decreases at enough large loads. However, a maximum of friction coefficients is observed for polyelectrolyte brushes, which is in contrast to the neutral brushes with monotonical dependence. [ABSTRACT FROM AUTHOR]

Polyelectrolyte solutions are more variable than uncharged macromolecule due to electrical interaction between charged molecules and surrounding counterions. Therefore, the subject of polyelectrolyte solutions has attracted a wide range of interests in both basic and applied research, and has also been extensively explored. However, the understanding of the molecular dynamics and conformation of polyelectrolytes in solution remains to be deepened, and universal consensus on some key issues have not been reached. Many methods have contributed to solving the above problems in different ways, including dielectric relaxation spectroscopy (DRS). In this perspective, we briefly reviewed the history of dielectric spectroscopic research on polyelectrolyte solution, with emphasis on summarizing our efforts. In particular, we expound the characteristics of DRS and its ability to obtain the internal information of the system of interest. Finally, we evaluate the advantages and limitations of the dielectric method and discussed future prospects of this field. [ABSTRACT FROM AUTHOR]

Polyelectrolytes are charged polymers comprising macromolecules in which substantial portions of the constituent units contain cationic (e.g., pyridinium, ammonium) or anionic (e.g., sulfonate, carboxylate) groups, which possess special functions from the features of counterions, such as dissociation to charged species, mechanical stability, phase behavior, etc. Therefore, functional polyelectrolytes have been widely applied in many fields. In this perspective, we present some progresses in the studies of poly(polyoxometalate)s, denoted as poly(POM)s, as a kind of new charged polymers/polyelectrolytes, by covalent bonding between the inorganic polyoxometalate (POM) clusters and the organic polymer chains. According to the distinct positions of POMs in polymer chain and functions of poly(POM)s, they are divided into the following four categories: crosslinked poly(POM); side-chain poly(POM); backbone poly(POM), including poly(POM)-conjugated polymer hybrid and block poly(POM)-polymer; and POM-based covalent organic framework (PCOF). This perspective introduces the synthesis methods of poly(POM) polyelectrolytes and their macromolecular and aggregate structural characteristics, while also focusing on their properties and functions. Their application areas include catalysis, thermal resistance, optical functions, fuel cells and batteries, etc. [ABSTRACT FROM AUTHOR]

We utilize molecular dynamics simulations to investigate the microstructures of ions and polyelectrolytes in aqueous solutions under external electric fields. By focusing on the multi-body interactions between ionic components and H2O molecules, as well as their responses to the external electric fields, we clarify several nontrivial molecular features of the ionic and polyelectrolyte solutions, such as the solvations of cations and anions, clustering of the ions, and dispersions/aggregations of polyelectrolyte chains, as well as the corresponding responses of H2O molecules in these contexts. Our simulations illustrate the variations in structures of ionic solutions caused by reversing the charge sign of the ions, and elucidate the disparity in structures between anionic and cationic polyelectrolyte solutions in the presence of the external electric fields. This work clarifies the mechanism for the alternations in complex multi-body interactions in aqueous solutions caused by the application electric field, which can contribute to the fundamental understanding of the physical and chemical natures of ion-containing and charged polymeric systems. [ABSTRACT FROM AUTHOR]

Conformational changes have been studied by molecular dynamics simulation in a complex of two oppositely charged polyelectrolytes and in a polyampholytic block copolymer consisting of these electrolytes on the surface of a spherical metal nanoparticle depending on its electric charge. A mathematical model is presented for the rearrangement of two macromolecular shells of different signs located on a charged spherical nanoparticle, and the rigidity of the polyelectrolyte chain depending on its charge has been assessed. The radial distributions of the average density of atoms of the polyelectrolyte complex and the block copolymer located on the surface of the charged spherical metal nanoparticle have been calculated. The oppositely charged polyelectrolytes in the complex, as well as block copolymer molecules, were found to tightly envelop the neutral spherical nanoparticle; as the absolute value of the nanoparticle charge increased, the macromolecular edge swelled by formation of two layers of oppositely charged polyelectrolytes or block copolymer fragments. [ABSTRACT FROM AUTHOR]

The interactions of polyelectrolyte poly (sodium styrene sulfonate or NaPSS) and anionic surfactants, sodium glycodeoxycholate (SGDC) and sodium tetradecyl sulfate (STS), as well as their combination (SGDC + STS) at different mole fraction ratios, were investigated using surface tension analysis. In the SGDC + STS binary mixture, when the amount of NaPSS (0.005–0.03%) increased from α SGDC 0.0 to 1.0, increasing the critical micellization concentration (cmc) of the mixtures. The minimum cmc values were found from 0.833 to 1.480 mmol L−1 in the presence of 0.03% of NaPSS. Clint, Rubingh, Motomura, and Rodenas approaches were used to evaluate the ideal cmc, activity coefficients (fi), interaction parameter (–β), micellar compositions (x), and ideal micellar composition of (xid) of SGDC + STS mixtures. Synergism has been demonstrated by the experimental values of c0m being lower than the ideal values in water. Moreover, by adding NaPSS from 0.005 to 0.03%, the synergism interaction was eliminated and antagonism behavior was developed. The standard Gibb's free energy of micellization ( Δ G m 0) and surface excess (Γ) and surface area per absorbed molecules (Amin) was decreased or increased depending on NaPSS amount in the SGDC + STS mixture with varying a SGDC . [ABSTRACT FROM AUTHOR]

Ionic diode‐based generators show great superiority in harvesting low‐frequency mechanical energy from human motions for various wearable applications. The major challenge is to improve their extremely limited output voltage for the miniaturization/simplicity of ionic diode‐based self‐powered devices as well as further improvement of mechanoelectric conversion performance. Herein, the construction of gradient polycation/polyanion heterojunction is demonstrated to vastly boost the output voltage, energy‐harvesting efficiency, and sensing performance of ionic diode. Besides an inherent potential at the polyanion/polycation heterojunction interface, the additional transmembrane potentials can be generated across gradient polyanion and polycation conductors of ionic diodes due to their gradient charge distribution. Consequently, the gradient ionic diode‐based generators produce much higher output voltage (306.53 mV) than previously reported homogeneous ones (4.1–135 mV). Meanwhile, the high output voltage imparts gradient ionic diode‐based generator with ultrahigh power density (50.16 µW cm−2 or 250.8 µW cm−3) and pressure‐perception sensitivity (43582 mV/MPa), which are dramatically increased by 162.76% and 128.71%, respectively, compare to those of homogeneous one. Impressively, the resulting diode‐based generators can generate ultralarge current density (≈0.52 mA cm−2) with ultralong discharge time (>400 s), thus enabling the continuous power generation under the low‐frequency pressure for various wearable and implantable applications. [ABSTRACT FROM AUTHOR]

Despite decades of research, the fundamental question of structure and morphology of the poly(3,‐4‐ethylenedioxythiophene):poly(styrene sulfonate) complex (PEDT: PSS) electrically conducting polymer remains open. Here, through a systematic study of the polymerization of 3,4‐ethylenedioxythiophene (EDT) on two series of sulfonated polystyrenes, i.e., PS‐co‐SSH and PS‐co‐SSNa, with per cent sulfonation 24 ≲ x ≲ 100, this study shows that the substrate polyelectrolyte not only affords charge compensation and processability, but also templates the morphology of the growing PEDT chain—whether extended, coiled or collapsed. This determines the electrical, electronic and optical properties of the resultant PEDT: PSS interpolyelectrolyte complexes, including their work function. This study calls this the Polyelectrolyte Template model. The PEDT: PSS complex retains memory of its polymerization morphology even after subsequent ion‐exchange, for example, to the same acid form. Electrical conductivity decreases sharply with decreasing x, and depends on whether the polymerization is templated with the H+ or Na+ form of the polyelectrolyte. The work function is less sensitive to x, but exhibits a transition from low to high work function (5.2–5.3 eV) when x exceeds a threshold, which indicates formation of a polar surface driven by molecular‐scale segregation of the PSS counteranion. This surface segregation also affects the ability of these complexes to inject holes into very large‐ionization‐energy semiconductors. [ABSTRACT FROM AUTHOR]

In this work, a family of bioactive waterborne polyurethanes (WPUs), based on glycerol ethoxylate (GE), hexamethylene diisocyanate (HDI) or isophorone diisocyanate (IPDI), with specific bioactivity on their chemical structures constituted by the amino acids: L-tyrosine (T), L-histidine (H) or L-glutamic acid (Glut), using a mass ratio of each component of 56/29/15%, respectively, was synthesized by a condensation reaction at 80 ºC for 3 h. In the GPC analysis, the P(HDI-T) shows the highest average molecular weight (Mn) (20,264 g mol−1), with a rod-like morphology, with a melting point of 240 ºC and with high resistance to endothermic degradation. IPDI-based WPUs exhibit a rough and amorphous structure, with a glass transition temperature around 120 ºC, regardless of the chemical structure of the amino acid present in their polymeric skeleton. The P(HDI-T) WPU it has the largest particle size. The in vitro biological evaluation reveals that the synthesized WPUs demonstrate to be non-hemolytic materials, benefiting the proliferation of important cells in the healing process such as monocytes and fibroblasts, and that they have antibacterial properties; evidencing that P(HDI-H) and P(IPDI-Glut) allow a 100% in vitro wound closure at 15 days. These novel bioactive synthetic polymers could be useful for the design of smart biomaterials as hydrogels made up of proteins using them as chemical crosslinker, taking advantage of the reactivity of the isocyanate groups. [ABSTRACT FROM AUTHOR]

[Display omitted] The instability and high electron-hole recombination have limited the application of black phosphorus (BP) as an excellent photocatalyst. To address these challenges, poly dimethyl diallyl ammonium chloride (PDDA), poly (allylamine hydrochloride) (PAH), and polyethyleneimine (PEI) are introduced to the functionalization of BP (F-BP), which can not only enhance its stability, but also boost the carrier transfer. Furthermore, a high-performance heterojunction photocatalyst is fabricated using F-BP and titania nanosheets (TNs) via a layer-by-layer self-assembly approach. The experimental outcomes unequivocally indicate that F-BP exhibits fast charge migration compared to BP. The density functional theory (DFT), in situ Kelvin-probe force microscopy (KPFM) and other advanced characterization techniques collectively unfold that PDDA modified BP can notably boost separation and propagation of charges, along with an enhanced carrier abundance. In summary, this novel strategy of using polyelectrolytes to enhance the electron transfer and the stability of BP permits immense potential in building next-generation BP-based high efficiency photocatalysts. [ABSTRACT FROM AUTHOR]

This concept paper elucidates the possible influence of the electrical double layer (EDL) and the polyelectrolytic nature of bacterial cell walls on the behavior of antimicrobial peptides (AMPs) and lipopeptides. It proposes that the presence of EDL adjacent to lipid membranes may play a crucial role in inducing peptide aggregation and conformational changes, thus affecting their antimicrobial activity. Furthermore, it emphasizes that the negatively charged components in both Gram‐positive and Gram‐negative bacterial cell walls may act as polyelectrolytes, effectively reducing the critical micellization concentration (CMC) of positively charged peptides and lipopeptides. This reduction is expected to facilitate their aggregation, potentially enhancing their accumulation at the bacterial membrane and increasing their effectiveness in disrupting membrane integrity and exerting antimicrobial activity. Therefore, understanding the interplay between EDL effects, polyelectrolytic properties of bacterial cell walls, and the behavior of antimicrobial peptides is essential for elucidating their mechanisms of action and optimizing their therapeutic potential. [ABSTRACT FROM AUTHOR]

Ionic memristors can emulate brain‐like functions of biological synapses for neuromorphic technologies. Apart from the widely studied excitatory‐excitatory and excitatory‐inhibitory synapses, reports on memristors with the inhibitory‐inhibitory synaptic behaviors remain a challenge. Here, the first biaxially inhibited artificial synapse is demonstrated, consisting of a solid electrolyte and conjugated microporous polymers bilayer as neurotransmitter, with the former serving as an ion reservoir and the latter acting as a confined transport. Due to the migration, trapping, and de‐trapping of ions within the nanoslits, the device poses inhibitory synaptic plasticity under both positive and negative stimuli. Remarkably, the artificial synapse is able to maintain a low level of stable nonvolatile memory over a long period of time (≈60 min) after multiple stimuli, with feature‐inferencing/‐training capabilities of neural node in neuromorphic computing. This work paves a reliable strategy for constructing nanochannel ionic memristive materials toward fully inhibitory synaptic devices. [ABSTRACT FROM AUTHOR]

The surface charge of nanoparticles or nanocarriers (NCs) plays a critical role in the vehicle function, distribution, and fate in drug delivery applications. Flash NanoPrecipitation (FNP) is a platform for producing block copolymer-stabilized NCs. We show that NC charge (measured as the ζ-potential) can be continuously tuned from +40 to −40 mV by using blends of neutral poly-(styrene)-block-poly-(ethylene glycol) (PS-b-PEG) with polyelectrolyte block copolymers, anionic poly-(styrene)-block-poly-(acrylic acid) (PS-b-PAA) or cationic poly-(styrene)-block-poly-(N,N-dimethylaminoethyl methacrylate) (PS-b-DMAEMA), while simultaneously controlling NC diameters between 40 and 180 nm. The dense polymer brush on the surface of these FNP NCs provides a better platform to test NC surface charge effects on cellular interactions than NC systems in which charge is applied onto hydrophobic surfaces. NC charge gradually increases as more PS-b-PEG is replaced with a polyelectrolyte stabilizer, where sparsely substituted NCs (1–20 wt %) have nearly neutral (|ζ| < 5 mV) followed by a region where ζ-potential increases with increasing polyelectrolyte substitution. The protein binding to negatively charged NCs is low and equivalent to the adsorption on PEG-coated NCs, which are normally considered as the gold standard in "stealth" low protein adsorbing surfaces. In contrast, as little as 1 mol % cationic polymer produces strong protein adsorption, and cellular uptake, even though the ζ-potentials are still near zero, |ζ| < 5 mV. Binding of the NCs to Tib67, HEK293T, and HepG2 cells is distinct. While cationic NCs are taken up by all cell lines, anionic NCs are only taken up by the macrophage-like Tib67 cells. These results are discussed in terms of the protein corona differences on the NCs and the receptor differences between these cell lines. This study shows that ζ-potential alone is inadequate to predict the biological identity of an NC formed by protein corona adsorption and interactions with different types of cells. [ABSTRACT FROM AUTHOR]

In recent decades, polyelectrolytes (PELs) have attracted significant interest owing to a surge in research dedicated to the development of new technologies and applications at the biological level. Polyelectrolytes are macromolecules of which a substantial portion of the constituent units contains ionizable or ionic groups. These macromolecules demonstrate varied behaviors across different pH ranges, ionic strengths, and concentrations, making them fascinating subjects within the scientific community. The aim of this review is to present a comprehensive survey of the progress in the application studies of polyelectrolytes and their derivatives in various fields that are vital for the advancement, conservation, and technological progress of the planet, including agriculture, environmental science, and medicine. Through this bibliographic review, we seek to highlight the significance of these materials and their extensive range of applications in modern times. [ABSTRACT FROM AUTHOR]

Organic polymers have been extensively studied over the last decades, and most of the research focused on the mechanical performance of the soils treated with polymer at different dosages without addressing the effects of the unique polymer characteristics such as molecular weight and concentrations of polymer solutions. This paper investigates an anionic polyelectrolyte, sodium polystyrene sulfonate (PSS) as a soil stabilizer. The effects of the molecular weight of PSS, concentrations of PSS solutions, and the dosages on the strength of a siliceous sandy subgrade soil are examined. Fracture toughness of the PSS-treated soil is determined and discussed based on semicircular bending test. Three molecular weights (1,000,000, 200,000, and 70,000 g/mol) along with solution concentrations of 10%, 17%, 23%, and 30% by weight are considered. The dosages of PSS solutions at 2%, 4%, 6%, and 8% by weight of dry soil are discussed. All the dosages studied showed strength improvement of the sandy soil that increased with concentrations of the PSS solutions as well as the increasing dosages. PSS with the highest molecular weight performed the best among all three molecular weights. The addition of the organic polymer also improved the fracture toughness of the soil, indicating better resistance to crack propagation. The stabilization mechanism in terms of particle linkage and aggregation morphology are examined using scanning electron microscope. Aggregation of the fine soil particles and binding between the fine and coarse soil grains are observed and discussed, which contribute to the improvement of mechanical strength of the soil. [ABSTRACT FROM AUTHOR]

The shale reservoir consists mainly of mud shale, characterized by its unique physical and chemical properties, extensive bedding, and micro-cracks. As a result, it is susceptible to hydration and dispersion, leading to the instability of the wellbore during drilling. To address this issue, chemical or physical methods are necessary to enhance the wellbore integrity and ensure stability during the drilling process. This paper focuses on simulating the biomimetic mineralization process to study the composite membrane structure formed by the deposition of montmorillonite and polyelectrolyte. The study investigates the reinforcement effect of the composite membrane on the wellbore wall. By examining the morphology and structure of montmorillonite and BPEI deposition films, the influence of deposition times and polyelectrolyte variations on the deposition film is analyzed. Additionally, the mechanical properties of the montmorillonite and BPEI deposition film are evaluated. The investigation also employs simulated drilling fluid circulation deposition to assess the reinforcement effect of the deposition film on the well wall. Experimental results indicate that the deposition film formed by montmorillonite and BPEI demonstrates a certain level of effectiveness in improving wellbore stability. These findings provide a solid basis for further research on process technology and offer new insights for ensuring the safety of shale oil reservoir drilling. [ABSTRACT FROM AUTHOR]

Fluorine-free single-component polyelectrolytes were developed via the hybridization of lithium methanesulfonylsulfonimide (LiMSSI) moieties to poly(ethylene glycol) (PEG) derivatives with different morphologies, and the relationship between the structure and its ionic conductivity was investigated. The PEG-LiMSSI derivatives with one, two, and three LiMSSI end groups were prepared via the concomitant Michael-type addition and lithiation of PEGs and N-methanesulfonylvinylsulfonimide. The ionic conductivity at 60 °C ranged from 1.8 × 10−7 to 2.0 × 10−4 S/cm. PEG-LiMSSI derivatives with one LiMSSI terminus and with two LiMSSI termini at both ends show higher ionic conductivity, that is as good as fluorine-free single-component polyelectrolytes, than that with two LiMSSI termini at one end and that with three LiMSSI termini. [ABSTRACT FROM AUTHOR]

AbstractThe naturally occurring polymers, chitosan (CH) and poly(N-vinyl-pyrrolidone (PVP), have attracted the interest of researchers in a variety of biomedical and pharmaceutical applications areas, such as drug delivery, cosmetics, and tissue engineering. However, PVP and CH have certain limitations for use in controlled aqueous CH/PVP mixed solutions. In this study aqueous solutions of PVP and CH with the same concentration of 10 g/l and pH 6 were mixed under atmospheric conditions. The effects of temperature and molar volume fraction, X1, of CH on the decreased dynamic viscosity of the CH/PVP mixed solutions were studied at various temperatures ranging from 15 °C to 80 °C. We highlighted that different regions can be distinguished in the aqueous CH/PVP complexes, depending on the composition and electrostatic interactions of the solutions, which are associated with significantly different phase behaviors. [ABSTRACT FROM AUTHOR]

The naturally occurring polymers chitosan (CH) and sodium carboxymethylcellulose (CMC) have attracted the interest of researchers in a variety of biomedical and pharmaceutical applications such as drug delivery, cosmetics, and tissue engineering. However, CMC and CH have certain limitations for use in controlled aqueous CMC/CH mixed solutions. In this study, aqueous solutions of CMC and CH with the same concentration of 0.5 g/l and pH 6 are mixed under atmospheric conditions. The effects of temperature and molar volume fraction X1 of CMC on the decreased electrical conductivity of CMC/CH mixed solutions were studied at different temperatures ranging from 15°C to 80°C. We highlighted that different regions can be distinguished in the aqueous CMC/CH complexes, depending on the composition and electrostatic interactions of the solutions, which are associated with significantly different phase behaviors. [ABSTRACT FROM AUTHOR]

An investigation was carried out on the feasibility of obtaining a reagent based on complex compounds for regulating the parameters of a drilling mud by introducing complex‑forming ferrous cations into a sodium lignosulfonate composition followed by additional modification with phosphonic compounds and obtaining a polyelectrolyte complex derived from anionic polyelectrolyte‑sodium lignosulfonate and modified cationic starch. The presence of functional groups in the sodium lignosulfonate sample studied capable of complexation was established by IR spectrometry. The determination of the optimal ratios of the starting components for the obtaining complex compounds using lignosulfonate, iron sulfate, and phosphonic compounds was carried by mathematical modelling with the Statistica 12 software package. The surface activity of the experimental samples was studied by a stalagmometric method (drop count method). The particle size distribution method using an SALD‑7101 laser analyzer was employed to study changes in the structure of the macromolecule of sodium lignosulfonate and a polyelectrolyte complex derived from sodium lignosulfonate and cationic starch. Obtaining a stable polyelectrolyte complex by selecting the optimal ratios of the anionic and cationic components involved measuring the dependence of the impedance of an electrochemical cell on the alternating currency frequency. The best mole ratio for preparation of the polyelectrolyte complex was 1:1. Feasibility was studied for using this lignosulfonate reagent based on complex compounds as a reagent for regulating the drilling mud parameters in the temperature range from 20° to 160-180°C. [ABSTRACT FROM AUTHOR]

In the field of preparing cosmetic formulations, recent advances recommend the usage of excipients derived from biocompatible materials. In this context, the present study aimed to prepare and characterize the curcumin-loaded Pickering emulsion for possible applications in cosmetic formulation. The coconut oil which is often the component of skin care formulations is used as the oily phase. Curcumin, which is well known for absorbing solar radiation, is expected to work synergistically with coconut oil towards improving the sun protection factor (SPF) of the formulation. Additionally, curcumin can also protect the intracellular components through its well-known antioxidant mechanisms. The Pickering emulsion of coconut oil into water was prepared using the composite colloidal particles derived from β-carboxymethyl chitosan (CMC) and Gelatin-A (GA) as the emulsifying agent. The reaction conditions in terms of the weight ratios of CMC and GA, the pH of the reaction medium, the oil volume fraction, and the homogenization speed were optimized to obtain the most stable Pickering emulsion. The obtained systems were physico-chemically characterized by dynamic light scattering, zeta potential, optical microscopy, and rheometric measurements. The final CMC-GA-stabilized emulsion demonstrated an oil droplet size of 100 µm and a SPFspectrophotometric (290–320 nm) value of 8.5 at a curcumin loading of 4 mg/mL. Additionally, the final formulation facilitated the uptake of curcumin into fibroblast (WI26) cells under in vitro conditions. Together, the investigation demonstrates a bio-inspired approach to prepare a curcumin-loaded green Pickering emulsion using biocompatible pharmaceutical grade excipients, which may find utility in cosmetic applications. [ABSTRACT FROM AUTHOR]

Presently, due to growing global energy demand and depletion of existing oil reservoirs, oil industry is focussing on development of novel and effective ways to enhance crude oil recovery and exploration of new oil reserves, which are typically found in challenging environment and require deep drilling in high temperature and high-pressure regime. The nanocelluloses with numerous advantages such as high temperature and pressure stability, ecofriendly nature, excellent rheology modifying ability, interfacial tension reduction capability, etc., have shown a huge potential in oil recovery over conventional chemicals and macro/micro sized biopolymers-based approach. In present review, an attempt has been made to thoroughly investigate the potential of nanocellulose (cellulose nanocrystals/nanofibers) in development of drilling fluid and in enhancement of oil recovery. The impact of various factors such as nanocellulose shape, charge density, inter-particle or inter-fibers interactions after surface functionalization, rheometer geometries, additives, post processing techniques, etc., which provides insight into the attributes of nanocellulose suspension and exemplify their behaviour during oil recovery have also been reviewed and discussed. Finally, the conclusion and challenges in utility of nanocellulose for oilfield applications are addressed. Knowing how to adjust/quantify nanocrystals/nanofibers shape and size; and monitor their interactions might promote their utility in oilfield industry. [ABSTRACT FROM AUTHOR]

The commercially available magnetic nanoparticles (MNPs) in the solid powder form are typically colloidally unstable under the aqueous environment and can easily settle out without modification. Thus, surface functionalization with polyelectrolyte is required to improve the colloidal stability of MNP systems prior to their applications. In this study, the effect of various factors during the functionalization process, including type of polyelectrolyte, solution pH, ionic strength and particle-to-polyelectrolyte ratio, on the colloidal stability of the functionalized MNPs was evaluated experimentally and theoretically. It was revealed that PSS-70 k and PDDA(M) imparted better colloidal stability toward the functionalized MNPs as compared to PEG, PSS-1000 k and PDDA(L). The optimal pH to produce PSS-70 k- and PDDA(M)-functionalized MNPs is found to be pH 3 and 11, respectively. In addition, the optimum MNP/polyelectrolyte mass ratio was revealed to be 1:5 and 1:0.5 for the synthesis of PSS-70 k- and PDDA(M)-functionalized MNP systems, respectively. The colloidal stability of both PSS-70 k- and PDDA(M)-functionalized MNPs was severely impeded by the presence of free ionic species in the solution during the functionalization process. Lastly, the mathematical analysis based on DLVO theory was consistent and well aligned with the experimental findings. [ABSTRACT FROM AUTHOR]

A coarse-grained model of linear polyfunctional weak charged biopolymers was implemented, formed of different proportions of acid-base groups resembling the composition of humic substances. These substances are mainly present in dissolved organic matter in natural water. The influence of electrostatic interactions computing methods, factors concerning the structure of the chain, different functional groups, and the ionic strength on polyelectrolytes were studied. Langevin dynamics with constant pH simulations were performed using the ESPResSO package and the Python-based Molecule Builder for ESPResSo (pyMBE) library. The coverage was fitted to a polyfunctional Frumkin isotherm, with a mean-field interaction between charged beads. The composition of the chain affects the charge while ionic strength affects both the charge and the radius of gyration. Additionally, the parameters intrinsic to the polyelectrolyte model were well reproduced by fitting the polyfunctional Frumkin isotherm. In contrast, the non-intrinsic parameters depended on the ionic strength. The method developed and applied to a polyfunctional polypeptide model, that resembles a humic acid, will be very useful for characterizing biopolymers with several acid-base functional groups, where their structure, the composition of the different functional groups, and the determination of the main intrinsic proton binding constants and their proportion are not exactly known. [ABSTRACT FROM AUTHOR]

Abstract This concept paper elucidates the possible influence of the electrical double layer (EDL) and the polyelectrolytic nature of bacterial cell walls on the behavior of antimicrobial peptides (AMPs) and lipopeptides. It proposes that the presence of EDL adjacent to lipid membranes may play a crucial role in inducing peptide aggregation and conformational changes, thus affecting their antimicrobial activity. Furthermore, it emphasizes that the negatively charged components in both Gram‐positive and Gram‐negative bacterial cell walls may act as polyelectrolytes, effectively reducing the critical micellization concentration (CMC) of positively charged peptides and lipopeptides. This reduction is expected to facilitate their aggregation, potentially enhancing their accumulation at the bacterial membrane and increasing their effectiveness in disrupting membrane integrity and exerting antimicrobial activity. Therefore, understanding the interplay between EDL effects, polyelectrolytic properties of bacterial cell walls, and the behavior of antimicrobial peptides is essential for elucidating their mechanisms of action and optimizing their therapeutic potential.

A coarse-grained model of linear polyfunctional weak charged biopolymers was implemented, formed of different proportions of acid-base groups resembling the composition of humic substances. These substances are mainly present in dissolved organic matter in natural water. The influence of electrostatic interactions computing methods, factors concerning the structure of the chain, different functional groups, and the ionic strength on polyelectrolytes were studied. Langevin dynamics with constant pH simulations were performed using the ESPResSO package and the Python-based Molecule Builder for ESPResSo (pyMBE) library. The coverage was fitted to a polyfunctional Frumkin isotherm, with a mean-field interaction between charged beads. The composition of the chain affects the charge while ionic strength affects both the charge and the radius of gyration. Additionally, the parameters intrinsic to the polyelectrolyte model were well reproduced by fitting the polyfunctional Frumkin isotherm. In contrast, the non-intrinsic parameters depended on the ionic strength. The method developed and applied to a polyfunctional polypeptide model, that resembles a humic acid, will be very useful for characterizing biopolymers with several acid-base functional groups, where their structure, the composition of the different functional groups, and the determination of the main intrinsic proton binding constants and their proportion are not exactly known.

Background and Objectives: Features of photostimulated adsorption of enzymes on a semiconductor substrate, leading to different changes in the sensitivity to glucose and hydrogen peroxide, were studied using the enzymes glucose oxidase and horseradish peroxidase as an example. Materials and Methods: Enzyme molecules were deposited on n-Si and p-Si substrates by photostimulated layer-by-layer adsorption from solution. Glucose oxidase and horseradish peroxidase were used as enzymes. The resulting structures were mounted in an electrochemical cell to measure the capacitance-voltage characteristics of the electrolyte-insulator-semiconductor contact, which were then used to determine the sensitivity of the sensor structures to glucose and hydrogen peroxide. Results: The results were analyzed taking into account photoelectronic processes in n-Si and p-Si semiconductor substrates. An increase in the sensitivity to the analyte from the use of photostimulated adsorption has been found for the structures obtained on the basis of n-Si, regardless of the type of immobilized enzyme. But for glucose oxidase molecules, the effect of photostimulation reaches 200%, and for horseradish peroxidase molecules it does not exceed 30%. The effect of photostimulated adsorption is explained by the charge exchange of surface electronic states at the Si/SiO2 interface upon illumination and the formation of induced dipoles that combine the charge of the enzyme molecule and the opposite charge of the Si/SiO2 interface after the illumination is turned off. Conclusion: The conducted studies can be applied in the development of a capacitive biosensor operating on the field effect, since taking into account the change in the charge state of the immobilized enzyme and the surface of the semiconductor signal converter makes it possible in some cases to significantly increase the sensitivity of the biosensor.

This review comprehensively explores the multifunctional applications of pectins derived from food waste and by-products, emphasizing their role as versatile biomaterials in the medical-related sectors. Pectins, known for their polyelectrolytic nature and ability to form hydrogels, influence the chemical composition, sensory properties, and overall acceptability of food and pharmaceutical products. The study presents an in-depth analysis of molecular parameters and structural features of pectins, such as the degree of esterification (DE), monosaccharide composition, galacturonic acid (GalA) content, and relative amounts of homogalacturonan (HG) and rhamnogalacturonan I (RG-I), which are critical for their technofunctional properties and biological activity. Emphasis is placed on pectins obtained from various waste sources, including fruits, vegetables, herbs, and nuts. The review also highlights the importance of structure–function relationships, especially with respect to the interfacial properties and rheological behavior of pectin solutions and gels. Biological applications, including antioxidant, immunomodulatory, anticancer, and antimicrobial activities, are also discussed, positioning pectins as promising biomaterials for various functional and therapeutic applications. Recalled pectins can also support the growth of probiotic bacteria, thus increasing the health benefits of the final product. This detailed review highlights the potential of using pectins from food waste to develop advanced and sustainable biopolymer-based products.

Galangin is a natural flavonol with high antioxidant properties and has a wide range characteristics of biological activity spectrum. Galangin has low solubility, permeability, and bioavailability, limiting its therapeutic use like many flavonoids. In this study, nano-sized polyelectrolyte liposomes were developed and characterized to overcome the properties that limit the use of galangin. The various parameters (phospholipid/solvent ratio, cholesterol/solvent ratio, time and galangin/solvent ratio) were optimized with a response surface methodology-central composite design to develop liposomes with maximum encapsulation efficiency using the thin-film hydration method. An optimum liposome formulation was developed with 93.77 ± 0.05% encapsulation efficiency, a spherical large unilamellar vesicle with a size of 485.5 ± 128.41 nm, and a zeta potential of − 48 ± 7 mV. The optimum liposome formulation was coated with polyelectrolyte biopolymer chitosan (CH) and gum arabic (GUA) using the layer-by-layer deposition method to improve its stability and drug release profile. The CH-liposome has a size of 208.05 ± 73.04 nm and a zeta potential of + 40 ± 5 mV. The GUA-CH-liposome has a size of 266.60 ± 8.49 nm and a zeta potential of − 6 mV. Fourier transform infrared spectroscopy analysis showed that galangin was encapsulated without disturbing the liposome structure and the polyelectrolyte coated the surface with electrostatic interaction. At the end of the in vitro release study, GUA-CH-liposome released 23.84% of galangin. Regarding stability, drug loading capacity of GUA-CH-liposome, which was 93.77 ± 0.05% on day 0, changed to 92.72 ± 0.51% at + 4 °C, 93.09 ± 0.01% at room temperature and 93.15 ± 0.01% at − 24 °C on day 28. [ABSTRACT FROM AUTHOR]

Polyelectrolyte–surfactant complexes (PESCs) have garnered significant attention due to their extensive range of biological and industrial applications. Most present applications are predominantly used in liquid or emulsion states, which limits their efficacy in solid material-based applications. Herein, pre-hydrolyzed polyacrylonitrile (HPAN) and quaternary ammonium salts (QAS) are employed to produce PESC electrospun membranes via electrospinning. The formation process of PESCs in a solution is observed. The results show that the degree of PAN hydrolysis and the varying alkyl chain lengths of surfactants affect the rate of PESC formation. Moreover, PESCs/PCL hybrid electrospun membranes are fabricated, and their antibacterial activities against both Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) are investigated. The resulting electrospun membranes exhibit high bactericidal efficacy, which enables them to serve as candidates for future biomedical and filtration applications. [ABSTRACT FROM AUTHOR]

Water‐enabled electricity generation technologies that are highly accessible and fundamentally clean are promising for next‐generation green energy. However, the challenge of scalability in both material processing and device fabrication greatly limits their practical applications. A high‐performance polyelectrolyte moist‐electric generator (MEG), which can be directly 3D printed for massive production and efficient integration, is reported. The printed MEG (p‐MEG) generates a high open‐circuit voltage of 0.8 V and a short‐circuit‐current density of 0.12 mA cm−2 by actively harvesting moisture from humid conditions. The synergistic effects of moisture gradient, ionic concentration gradient, and ion diffusion gradient, which remarkably enhance the driving force to separate ion pairs and notably facilitate the directional ion transport, are responsible for the high power generation performance of p‐MEG, as further backed up by in situ ion dynamics investigations and molecular simulations. When connected in serial and parallel, hundreds of p‐MEGs can deliver a high voltage of more than 180 V and a current of more than 1 mA. A constructed "moisture‐powered cup lamp" that lights up for hours further demonstrates the practicability of p‐MEG. This work provides a feasible and scalable 3D printing approach for the next‐generation environment‐adaptive self‐powered system. [ABSTRACT FROM AUTHOR]

In recent decades, there has been increased attention to the role of layer-by-layer assembled bio-polymer 3D structures (capsules, beads, and microgels) for biomedical applications. Such free-standing multilayer structures are formed via hard templating onto sacrificial cores such as vaterite CaCO3 crystals. Immobilization of these structures onto solid surfaces (e.g., implants and catheters) opens the way for the formulation of advanced bio-coating with a patterned surface. However, the immobilization step is challenging. Multiple approaches based mainly on covalent binding have been developed to localize these multilayer 3D structures at the surface. This work reports a novel strategy to formulate multilayer surface-supported microgels (ss-MG) directly on the surface via hard templating onto ss-CaCO3 pre-grown onto the surface via the direct mixing of Na2CO3 and CaCl2 precursor solutions. ss-MGs were fabricated using biopolymers: polylysine (PLL) as polycation and three polyanions—hyaluronic acid (HA), heparin sulfate (HS), and alginate (ALG). ss-MG biodegradation was examined by employing the enzyme trypsin. Our studies indicate that the adhesion of the ss-MG to the surface and its formation yield directly correlate with the mobility of biopolymers in the ss-MG, which decreases in the sequence of ALG > HA > HS-based ss-MGs. The adhesion of HS-based ss-MGs is only possible via heating during their formation. Dextran-loading increases ss-MG formation yield while reducing ss-MG shrinking. ss-MGs with higher polymer mobility possess slower biodegradation rates, which is likely due to diffusion limitations for the enzyme in more compact annealed ss-MGs. These findings provide valuable insights into the mechanisms underlying the formation and biodegradation of surface-supported biopolymer structures. [ABSTRACT FROM AUTHOR]

Electrostatic self-assembly of macroions is an emerging area with great potential in the development of nanoscale functional objects, where photo-irradiation responsiveness can either elevate or suppress the self-assembly. The ability to control the size and shape of macroion assemblies would greatly facilitate the fabrication of desired nano-objects that can be harnessed in various applications such as catalysis, drug delivery, bio-sensors, and actuators. Here, we demonstrate that a polyelectrolyte with a size of 5 nm and multivalent counterions with a size of 1 nm can produce well-defined nanostructures ranging in size from 10–1000 nm in an aqueous environment by utilizing the concept of electrostatic self-assembly and other intermolecular non-covalent interactions including dipole–dipole interactions. The pH- and photoresponsiveness of polyelectrolytes and azo dyes provide diverse parameters to tune the nanostructures. Our findings demonstrate a facile approach to fabricating and manipulating self-assembled nanoparticles using light and neutron scattering techniques. [ABSTRACT FROM AUTHOR]

Xanthan gum (XG) is a carbohydrate polymer with anionic properties that is widely used as a rheology modifier in various applications, including foods and petroleum extraction. The aim was to investigate the effect of Na+, K+, and Ca2+ on the physicochemical properties of XG in an aqueous solution as a function of temperature. Huggins, Kraemer, and Rao models were applied to determine intrinsic viscosity, [η], by fitting the relative viscosity (ηrel) or specific viscosity (ηsp) of XG/water and XG/salt/water solutions. With increasing temperature in water, Rao 1 gave [η] the closest to the Huggins and Kraemer values. In water, [η] was more sensitive to temperature increase (~30% increase in [η], 20–50 °C) compared to salt solutions (~15–25% increase). At a constant temperature, salt counterions screened the XG side-chain-charged groups and decreased [η] by up to 60% over 0.05–100 mM salt. Overall, Ca2+ was much more effective than the monovalent cations in screening charge. As the salt valency and concentration increased, the XG coil radius decreased, making evident the effect of shielding the intramolecular and intermolecular XG anionic charge. The reduction in repulsive forces caused XG structural contraction. Further, higher temperatures led to chain expansion that facilitated increased intermolecular interactions, which worked against the salt effect. [ABSTRACT FROM AUTHOR]

Compared to the charge–charge interaction, the role of the dipole‐dipole interaction has long been ignored in the phase behaviors of charged macromolecules in solutions. Charged macromolecules in solutions exhibit rich phase behaviors due to their complexity and they have been studied extensively. Phase separation can happen for charged macromolecules in the presence of monovalent salt, multivalent salt, and oppositely charged polymers, surfactants, etc., and for more advanced charged macromolecules such as polyzwitterions and polyampholytes, the phase diagram is even richer. In this perspective, the unacknowledged role of dipole‐dipole interaction in the phase behaviors of charged macromolecular solutions will be introduced. Dipolar polymers can form complex, self‐regulating structures which can be employed in various fields from drug‐delivery systems to next‐generation polymers. More importantly, it will shed light on how some of the life's basic and coherent structures such as biomolecular condensates and membrane‐less organelles are assembled and built by charged biomacromolecules such as DNA, RNA, and proteins. [ABSTRACT FROM AUTHOR]

The use of technology in drinking water treatment plants can be employed to reduce the uncertainty between urban water supply and demand. This study introduces the application of effluent treatment in drinking water treatment plants to reduce the generated effluent and balance groundwater resources. To achieve this, poly-electrolyte compounds were employed to treat the generated effluent in drinking water treatment plants, resulting in significant sedimentation of the Effluent volume and increased availability of water to meet the demands. In the drinking water treatment plants of Tehran city, to compensate for aquifer deficits, 50 million cubic meters of water per year were discharged as effluent from the cycle. However, by modifying the recycling process and utilizing poly-electrolyte, it is possible to reintegrate this water into the cycle. This water volume can be utilized as a substitute for exploiting groundwater resources. To assess the effectiveness and prioritize water allocation, three technical, economic, and social criteria were defined and calculated for each water treatment plant. To evaluate the impact of this process change on the groundwater level, a hybrid model called ANN–WOA was utilized. Based on this, four variables, including groundwater level, recharge, precipitation, and groundwater discharge, were defined as input variables to the model. 10 years was used for training, and 2 years was used for testing the model. Ultimately, the quantitative improvement of the groundwater was assessed the downstream of each water treatment plant using an appropriate index of desirability. The economic index value for allocation and the level of social satisfaction based on stakeholders' perspectives were completed. Ultimately, in the SWARA–COPRAS multi-criteria decision-making model, the prioritization of allocation for each water treatment plant was determined. The results demonstrated that by substituting this water volume, the desirability index increased by an average of 23%, which can be effective in balancing groundwater resources. Furthermore, the results indicated that the priority for allocation was given to the industrial sector, followed by the nearest green spaces available. The findings of this study illustrate that the use of new technologies in effluent treatment plants can be effective in reducing the exploitation of groundwater resources and achieving groundwater balance. [ABSTRACT FROM AUTHOR]

The behavior of surface-active substances (surfactants) is studied using the examples of lignosulfonate (LS) and sodium dodecyl sulfate (SDS) in aqueous and nitric acid media as promising additives for the nitric acid leaching of refractory ore concentrates. The effect the temperature (15–70°С) and concentrations of the surfactant (Csurfactant = 0.02–200 g/dm3) and nitric acid ( = 0.1–10 g/dm3) have on the surface tension, critical concentration of micelles (CMC), electrical conductivity, pH, and optical density of solutions is established. The critical association of concentration is determined for lignosulfonate: CLS ~ 0.13–0.14 mol/dm3. An increase in the surface activity of lignosulfonate is noted upon raising the temperature of and adding nitric acid to an LS–H2O system. The established effects (a drop in σl–g) are explained by an increase in the coefficient of diffusion of LS macromolecules and a change in the intensity of the associative-dissociative processes of counterions and the LS polyanion. The positive effect nitric acid has on the surface activity of SDS is noted and found to reduce surface tension at the liquid–gas interface and CMCs. Associative processes in SDS–HNO3 systems are also confirmed by measuring the optical density of the considered systems. [ABSTRACT FROM AUTHOR]

Abstract Ionic memristors can emulate brain‐like functions of biological synapses for neuromorphic technologies. Apart from the widely studied excitatory‐excitatory and excitatory‐inhibitory synapses, reports on memristors with the inhibitory‐inhibitory synaptic behaviors remain a challenge. Here, the first biaxially inhibited artificial synapse is demonstrated, consisting of a solid electrolyte and conjugated microporous polymers bilayer as neurotransmitter, with the former serving as an ion reservoir and the latter acting as a confined transport. Due to the migration, trapping, and de‐trapping of ions within the nanoslits, the device poses inhibitory synaptic plasticity under both positive and negative stimuli. Remarkably, the artificial synapse is able to maintain a low level of stable nonvolatile memory over a long period of time (≈60 min) after multiple stimuli, with feature‐inferencing/‐training capabilities of neural node in neuromorphic computing. This work paves a reliable strategy for constructing nanochannel ionic memristive materials toward fully inhibitory synaptic devices.

This study was executed in order to further improve the emulsion stability of chitosan/gum arabic composite particles and to regulate the rheological properties of high internal phase emulsions stabilized by it. Chitosan/gum arabic composite particles were prepared by different treatments and were used to stabilize high internal phase emulsions. The effects of the structure and properties of the particles on the structure, rheological properties and stability of high internal phase emulsions were explored. The results showed that compared with the control group (pH 5.0), ultrasonic and heat treatments significantly increased the yield of composite particles. There was no significant difference in the particle size or stability of the high internal phase emulsions stabilized by the treated and control composite particles, while the oil binding capacity and viscoelasticity were significantly improved. pH increase to 7.0 and sodium tripolyphosphate crosslinking had a negative effect on the yield of particles, making the composite particles exhibit poor emulsion stability and oil binding ability. The above findings showed that ultrasonic and heat treatments could improve the stability and adjust the rheological properties of chitosan/gum arabic composite particle-stabilized high internal phase emulsion, which shows potential in food texture regulation and fat substitutes with different textures.

Poly(acrylamide-co-acrylic acid) (P(AAm-co-AA)) hydrogels are highly tunable and pH-responsive materials frequently used in biomedical applications. The swelling behavior and mechanical properties of these gels have been extensively characterized and are thought to be controlled by the protonation state of the acrylic acid (AA) through the regulation of solution pH. However, their tribological properties have been underexplored. Here, we hypothesized that electrostatics and the protonation state of AA would drive the tribological properties of these polyelectrolyte gels. P(AAm-co-AA) hydrogels were prepared with constant acrylamide (AAm) concentration (33 wt%) and varying AA concentration to control the amount of ionizable groups in the gel. The monomer:crosslinker molar ratio (200:1) was kept constant. Hydrogel swelling, stiffness, and friction behavior were studied by systematically varying the acrylic acid (AA) concentration from 0-12 wt% and controlling solution pH (0.35, 7, 13.8) and ionic strength (I = 0 or 0.25 M). The stiffness and friction coefficient of bulk hydrogels were evaluated using a microtribometer and borosilicate glass probes as countersurfaces. The swelling behavior and elastic modulus of these polyelectrolyte hydrogels were highly sensitive to solution pH and poorly predicted the friction coefficient (µ), which decreased with increasing AA concentration. P(AAm-co-AA) hydrogels with the greatest AA concentrations (12 wt%) exhibited superlubricity (µ = 0.005 ± 0.001) when swollen in unbuffered, deionized water (pH = 7, I = 0 M) and 0.5 M NaOH (pH = 13.8, I = 0.25 M) (µ = 0.005 ± 0.002). Friction coefficients generally decreased with increasing AA and increasing solution pH. We postulate that tunable lubricity in P(AAm-co-AA) gels arises from changes in the protonation state of acrylic acid and electrostatic interactions between the probe and hydrogel surface.