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The Boyle temperature, TB, for an n-segment polymer in solution is the temperature where the second osmotic virial coefficient, A2, is zero. This characteristic is of interest for its connection to the polymer condensation critical temperature, particularly for n → ∞. TB can be measured experimentally or computed for a given model macromolecule. For the latter, we present and examine two approaches, both based on the Mayer-sampling Monte Carlo (MSMC) method, to calculate Boyle temperatures as a function of model parameters. In one approach, we use MSMC calculations to search for TB, as guided by the evaluation of temperature derivatives of A2. The second approach involves numerical integration of an ordinary differential equation describing how TB varies with a model parameter, starting from a known TB. Unlike general MSMC calculations, these adaptations are appealing because they neither invoke a reference for the calculation nor use special averages needed to avoid bias when computing A2 directly. We demonstrate these methods by computing TB lines for off-lattice linear Lennard-Jones polymers as a function of chain stiffness, considering chains of length n ranging from 2 to 512 monomers. We additionally perform calculations of single-molecule radius of gyration Rg and determine the temperatures Tθ, where linear scaling of R g 2 with n is observed, as if the polymers were long random-walk chains. We find that Tθ and TB seem to differ by 6% in the n → ∞ limit, which is beyond the statistical uncertainties of our computational methodology. However, we cannot rule out systematic error relating to our extrapolation procedure as being the source of this discrepancy. [ABSTRACT FROM AUTHOR]

Nonlinear response theory is employed to derive a closure to the polymer reference interaction site model equation. The closure applies to a liquid of neutral polymers at melt densities. It can be considered a molecular generalization of the mean spherical approximation (MSA) closure of Lebowitz and Percus to the atomic Ornstein–Zernike (OZ) equation and is similar in some aspects to the reference "molecular" MSA (R-MMSA) closure of Schweizer and Yethiraj to PRISM. For a model binary blend of freely-jointed chains, the new closure predicts an unmixing critical temperature, Tc, via the susceptibility route that scales linearly with molecular weight, N, in agreement with Flory theory. Predictions for Tc of the new closure differ greatest from those of the R-MMSA at intermediate N, the latter being about 40% higher than the former there, but at large N, both theories give about the same values. For an isotopic blend of polyethylene, the new and R-MMSA closures predict a Tc about 25% higher than the experimental value, which is only moderately less accurate than the prediction of atomic OZ-MSA theory for Tc of methane. In this way, the derivation and its consequences help to identify the ingredients in a theory needed to properly model the equilibrium properties of a polymeric liquid at both short and long lengthscales. [ABSTRACT FROM AUTHOR]

Even though dilute (unentangled) polymer solutions cannot act as gel-like sieving media, it has been shown that they can be used to separate DNA molecules in capillary electrophoresis. The separation then comes from sporadic, independent DNA–polymer collisions. We study polymer–polymer collisions in nanochannels (i.e., channels that are smaller than the normal size of the polymers), a situation where a polyelectrolyte is forced to migrate "through" isolated uncharged molecules during electrophoresis. We use Langevin dynamics simulations to explore the nature of these collisions and their effect on the net motion of the two polymer chains. We identify several types of collisions, including some that are unique to nanochannels. When the uncharged polymer is much larger than the polyelectrolyte, the system is reminiscent of gel electrophoresis, and we propose a modified empirical reptation model to explain the data, with an orientation factor that depends on the tube diameter. We also observe that the duration of a collision is a non-monotonic function of the polymer size ratio when the two chains are of comparable size, a surprising resonance-like phenomenon, which, combined with the asymmetric nature of molecular conformations during collision, suggests possible ratchet-like mechanisms that could be used to sort polyelectrolytes in nanodevices. [ABSTRACT FROM AUTHOR]

Polymers are known to wet nanopores with high surface energy through an atomically thin precursor film followed by slower capillary filling. We present here light interference spectroscopy using a mesoporous membrane-based chip that allows us to observe the dynamics of these phenomena in situ down to the sub-nanometer scale at milli- to microsecond temporal resolution. The device consists of a mesoporous silicon film (average pore size 6 nm) with an integrated photonic crystal, which permits to simultaneously measure the phase shift of thin film interference and the resonance of the photonic crystal upon imbibition. For a styrene dimer, we find a flat fluid front without a precursor film, while the pentamer forms an expanding molecular thin film moving in front of the menisci of the capillary filling. These different behaviors are attributed to a significantly faster pore-surface diffusion compared to the imbibition dynamics for the pentamer and vice versa for the dimer. In addition, both oligomers exhibit anomalously slow imbibition dynamics, which could be explained by apparent viscosities of six and eleven times the bulk value, respectively. However, a more consistent description of the dynamics is achieved by a constriction model that emphasizes the increasing importance of local undulations in the pore radius with the molecular size and includes a sub-nanometer hydrodynamic dead, immobile zone at the pore wall but otherwise uses bulk fluid parameters. Overall, our study illustrates that interferometric, opto-fluidic experiments with mesoporous media allow for a remarkably detailed exploration of the nano-rheology of polymeric liquids. [ABSTRACT FROM AUTHOR]

Cytoskeletal gels are engineered prototypes that mimic the contractile behavior of a cell in vitro. They are composed of an active polymer matrix and a liquid solvent. Their contraction kinetics is governed by two dynamic phenomena: mechanotransduction (molecular motor activation) and solvent diffusion. In this paper, we solve the transient problem for the simple case of a thin gel slab in uniaxial contraction under two extreme conditions: motor-limited or slow motor (SM) activation regime, and diffusion-limited or fast motor (FM) activation regime. The former occurs when diffusion is much faster than mechanotransduction, while the latter occurs in the opposite case. We observe that in the SM regime, the contraction time scales as t / t 0 ∼ (λ / λ 0) − 3 , with t 0 being the nominal contraction time, and λ and λ 0 being the final and initial stretches of the slab. t 0 is proportional to 1 / w ˙ , where w ˙ is the average mechanical power generated by the molecular motors per unit reference (dry polymer) volume. In the FM regime, the contraction time scales as t / t 1 ∼ (1 − λ / λ 0) 2 , with t 1 being the nominal contraction time, here proportional to the ratio L 2 / D , where L is the reference (dry polymer) thickness, and D is the diffusivity of the solvent in the gel. The transition between the SM and FM regimes is defined by a characteristic power density w ˙ ∗ , where w ˙ ≪ w ˙ ∗ gives the SM regime and w ˙ ≫ w ˙ ∗ gives the FM regime. Intuitively, w ˙ ∗ is proportional to D / L 2 , where, at a given power density w ˙ , a thinner gel slab (smaller L) or including smaller solvent molecules (higher D) is more likely to be in the SM regime given that solvent diffusion will occur faster than motor activation. [ABSTRACT FROM AUTHOR]

Conventional theories of weak polyelectrolytes are either computationally prohibitive to account for the multidimensional inhomogeneity of polymer ionization in a liquid environment or oversimplistic in describing the coupling effects of ion-explicit electrostatic interactions and long-range intrachain correlations. To bridge this gap, we implement the Ising density functional theory (iDFT) for ionizable polymer systems using the single-chain-in-mean-field algorithm. The single-chain-in-iDFT (sc-iDFT) shows significant improvements over conventional mean-field methods in describing segment-level dissociation equilibrium, specific ion effects, and long-range intrachain correlations. With an explicit consideration of the fluctuations of polymer configurations and the position-dependent ionization of individual polymer segments, sc-iDFT provides a faithful description of the structure and thermodynamic properties of inhomogeneous weak polyelectrolyte systems across multiple length scales. [ABSTRACT FROM AUTHOR]

Using phase-field simulations, we investigate the bulk coarsening dynamics of ternary polymer solutions undergoing a glass transition for two models of phase separation: diffusion only and with hydrodynamics. The glass transition is incorporated in both models by imposing mobility and viscosity contrasts between the polymer-rich and polymer-poor phases of the evolving microstructure. For microstructures composed of polymer-poor clusters in a polymer-rich matrix, the mobility and viscosity contrasts significantly hinder coarsening, effectively leading to structural arrest. For microstructures composed of polymer-rich clusters in a polymer-poor matrix, the mobility and viscosity contrasts do not impede domain growth; rather, they change the transient concentration of the polymer-rich phase, altering the shape of the discrete domains. This effect introduces several complexities to the coarsening process, including percolation inversion of the polymer-rich and polymer-poor phases—a phenomenon normally attributed to viscoelastic phase separation. [ABSTRACT FROM AUTHOR]

We study phase equilibria in a minimal model of charge-regulated polymer solutions. Our model consists of a single polymer species whose charge state arises from protonation-deprotonation processes in the presence of a dissolved acid, whose anions serve as screening counterions. We explicitly account for variability in the polymers' charge states. Homogeneous equilibria in this model system are characterised by the total concentration of polymers, the concentration of counter-ions and the charge distributions of polymers which can be computed with the help of analytical approximations. We use these analytical results to characterise how parameter values and solution acidity influence equilibrium charge distributions and identify for which regimes uni-modal and multi-modal charge distributions arise. We then study the interplay between charge regulation, solution acidity and phase separation. We find that charge regulation has a significant impact on polymer solubility and allows for non-linear responses to the solution acidity: Re-entrant phase behaviour is possible in response to increasing solution acidity. Moreover, we show that phase separation can yield to the coexistence of local environments characterised by different charge distributions. [ABSTRACT FROM AUTHOR]

The absence of chain ends makes ring polymers distinctly different from their linear analogues. The intrinsic viscosity, complex viscosity and the dielectric relaxation of ring polymers are investigated within the tenets of the optimized Rouse–Zimm theory. The distance dependent excluded volume interactions (EVIs) are obtained from Flory's mean field theory. The hydrodynamic interactions (HIs) between the pairs of monomers are estimated using the preaveraged Oseen tensor. The intrinsic viscosity of linear and ring polymers both with and without EVI are compared as a function of ring size. A monotonically increasing trend of the intrinsic viscosity is observed in both cases. The intrinsic viscosity of both linear and ring polymers both with and without EVI show a very good agreement with the experimental results of polystyrene over a wide range of molecular weights in both good and theta solvents, respectively. The fractal dimensions of the ring polymers with EVI lie between that of a random walk and a self-avoiding walk model of linear polymers in three dimensions. The ring size increases with EVI and the effect of EVI is stronger on larger rings than that on smaller rings. The dielectric relaxation follow a connectivity independent universal scaling behavior at low and high frequency regions. The imaginary part of the complex dielectric susceptibility displays a local maxima in the intermediate frequency region, which reveals a structure dependent behavior of the rings. The theoretically calculated dielectric loss of ring polymers with HI matches well with those obtained from experiments. [ABSTRACT FROM AUTHOR]

Due to the importance of supercapacitors in electronic storage devices, improving their efficiency is one of the topics that has attracted the attention of many researchers. Choosing the proper electrolyte for supercapacitors is one of the most significant factors affecting supercapacitors' performance. In the present paper, we compare liquid electrolytes (ionic liquid electrolytes) and solid electrolytes (polymer electrolytes) by molecular dynamics simulation to summarize their pros and cons. We consider polymer electrolytes in linear and network configurations. The results show that although ionic liquid-based supercapacitors have a larger differential capacitance since they have a smaller operation voltage, the energy stored is less than polymer electrolyte-based supercapacitors. Also, our investigations indicate that polymer electrolyte-based supercapacitors have more mechanical stability. Therefore, they can be considered a very suitable alternative to liquid electrolyte-based supercapacitors since they do not have known liquid electrolyte problems and display better performance. [ABSTRACT FROM AUTHOR]

We study a solution of interacting semiflexible polymers with curvature energy in poor-solvent conditions on the d-dimensional cubic lattice using mean-field theory and Monte Carlo computer simulations. Building upon past studies on a single chain, we construct a field-theory representation of the system and solve it within a mean-field approximation supported by Monte Carlo simulations in d = 3. A gas-liquid transition is found in the temperature-density plane that is then interpreted in terms of real systems. Interestingly, we find this transition to be independent of the bending rigidity. Past classical Flory–Huggins and Flory mean-field results are shown to be particular cases of this more general framework. Perspectives in terms of guiding experimental results towards optimal conditions are also proposed. [ABSTRACT FROM AUTHOR]

Membrane‐based CO2 separation is a promising technology compared to traditional processes, presenting advantages such as superior energy efficiency and reduced operational costs. This study investigates the enhancement of CO₂/N₂ separation performance by incorporating ionic liquid [hmim][Tf₂N] into polysulfone membranes. The membranes were produced with 5, 10, and 20 wt% IL, and their permeability was measured at 25°C under pressures of 1 and 4 bar. Stability tests were also conducted. At 1 bar, the membrane with 20 wt% IL exhibited the highest CO₂ permeability of 342.27 Barrer, while the membrane with 5 wt% IL demonstrated the best ideal selectivity for CO₂/N₂ of 27.87. At 4 bar, the membrane with 5 wt% IL showed the highest ideal selectivity for CO₂/N₂ of 40.81, with a CO₂ permeability of 144.26 Barrer. Leaching tests indicated potential integrity loss in ionic liquid composite polymer membranes at high pressures. Specifically, the CO₂ permeability of the PSF‐[hmim][Tf₂N] 5 wt% membrane increased continuously post‐testing due to IL leaching. However, the performance of the membranes remained stable at lower pressures (1 bar). These findings suggest that the produced membranes achieve higher permeability, CO₂/N₂ selectivity, and CO₂ diffusivity, making them suitable for post‐combustion gas separation applications. [ABSTRACT FROM AUTHOR]

Ultrafiltration polymer inclusion membranes (UPIMs) have become increasingly significant for the separation and purification of heavy metals from industrial wastes and wastewater due to their convenience compared to other liquid membranes. A novel process for cadmium separation and recovery has been developed using biodegradable ion carriers, specifically room temperature ionic liquids with various molecular structures. This innovation has greatly enhanced the efficiency and application of UPIMs for cadmium separation, while also providing the membranes with unique functional properties. In this study, various UPIMs were produced using polyvinyl fluoride hexafluoropropylene (PVDF‐co‐HPF) as the base polymer, different plasticizers, and symmetric room temperature ionic liquids as ion carriers. The ability of these membranes to extract cadmium ions was evaluated, demonstrating a removal rate of 9.70 μmol s−1 from a 25 ppm Cd(II) solution under optimum conditions. The selectivity and stability of the optimized UPIM were examined under different conditions to obtain a deeper insight into of its performance. The morphological characteristics of the optimized UPIM were examined using scanning electron microscopy and atomic force microscopy techniques. [ABSTRACT FROM AUTHOR]

A novel and effective adsorbent based on magnetic polymeric ionic liquid nanocomposite-coated hollow fiber membrane (MPILNC-HFM) was developed and applied for magnetic solid phase extraction of Pb (II) and Cu (II) from environmental water and fruit juice samples with microinjection sampling-flame atomic absorption spectrometry (MIS-FAAS). During extraction process, the adsorbent coated on the surface of the hollow fiber can be removed from the solution using tweezers without using a magnet. Additionally, the need to use a centrifuge during adsorption and desorption steps is also eliminated, thereby increasing the speed, simplicity, and efficiency of the extraction process. The nanocomposite characterized through Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and energy-dispersive x-ray (EDX) analyses to ensure its applicability. The experimental parameters were optimized by applying one-variable-at the-time (OVAT) approach. Under optimal conditions, limits of detection were achieved 16.5 µg L−1 for Pb (II) and 20.4 µg L−1 for Cu (II), respectively, with relative standard deviations up to 7.9% and relative recoveries in the range of 91.8%–02.2%. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis of novel polymeric ionic liquids by introducing quaternary ammonium groups into cross-linkable ionic liquids. • Introduction of polymeric ionic liquids containing quaternary ammonium groups for the preparation of novel high-temperature proton exchange membrane materials. • The proton conductivity of OPBI-PIL-30 % membrane at 180 °C was 113.94 mS cm−1. • The phosphoric acid retention of the OPBI-PIL-30 % membrane reached 86.89 % after 240 h of testing at 160 °C in anhydrous environment. • After immersion in Fenton's reagent (3 % H 2 O 2 , 4 ppm FeSO 4) for 144 h, the proton conductivity of the OPBI-PIL-30 % membrane was 135.35 mS cm−1. • OPBI-PIL-20 % combines both excellent proton conductivity and mechanical properties, obtaining the highest peak power density of 436.19 mW cm−2 at 160 ℃. A series of membrane materials suitable for high-temperature proton exchange membranes (HT-PEM) were successfully prepared by introducing polymeric ionic liquids (PILs) containing quaternary ammonium groups into ether-bonded polybenzimidazole (OPBI). The structure of the cross-linked membrane has a strong interaction with phosphoric acid (PA), which enhances proton transport and PA retention. To ensure better overall performance of the cross-linked membrane, the optimal PIL content is 30 wt% (OPBI-PIL-30 %). The PA uptake of OPBI-PIL-30 % membrane was 323.24 %, and the proton conductivity at 180 ℃ was 113.94 mS cm−1, which was much higher than that of OPBI membrane. It is noteworthy that the PA retention of OPBI-PIL-30 % membrane could reach 71.38 % after 240 h of testing under the harsh environment of 80 ℃/40 % RH. The membrane showed better acid retention capacity of 86.89 % at 160 ℃ under anhydrous environment. The OPBI-PIL-20 % membrane achieved the maximum power density of 436.19 mW cm−2, attributed to its favorable mechanical characteristics and proton conductivity. By these excellent properties, it is shown that OPBI-PIL-X membranes containing quaternary ammonium groups have the potential to be applied in high temperature proton exchange membrane fuel cells (HT-PEMFCs). [ABSTRACT FROM AUTHOR]

Polymer flooding is a prominent chemical enhanced oil recovery (CEOR) method that involves the injection of polymer solution into the oil reservoirs to improve the sweep efficiency and maximize the ultimate oil recovery. Selecting an appropriate polymer type, molecular weight, and concentration is crucial for success of any polymer flooding project. This paper studies the flow behavior of HPAM-based EOR polymers with different molecular weights through porous media. Dynamic adsorption and injectivity tests were performed through 5 Darcies sandpacks using polymer solutions prepared with low (LM; 8–10 MDa) and high (HM; 20–25 MDa) molecular weight polymers. Polymer solutions with different target viscosity values of 7, 15 and 30 cP were flooded through sandpacks at the reservoir temperature of 80 ºC and pore pressure of 1000 psi. The results showed that HM solutions with different target viscosity have higher polymer retention through sandpacks compared to LM solutions. Furthermore, results of residual resistance factor (RRF) measurements were in line with dynamic adsorption tests results. That is, permeability reduction due to irreversible polymer retention was higher when HM polymer solutions were injected. Furthermore, the results showed that although the resistance factor (RF) and in-situ viscosity of HM and LM polymers are in the same range, however, shear thickening regime becomes pronounced in the case of HM polymer with higher target viscosity. Polymer relaxation time measurements, and consequently, Deborah number calculations were performed to describe the shear thickening behavior by polymers viscoelastic characteristics. Results demonstrate that occurrence of shear thickening regime is controlled by Deborah number which is a function of polymer molecular weight, polymer concentration and injection rate. These results shed light on the importance of the selection of optimal polymer molecular weight and concentration during the design of polymer flooding projects. [ABSTRACT FROM AUTHOR]

The polymorphic behavior of conjugated polymers enables tunable optoelectronic properties, but their transport mechanism remains elusive due to the inherent complexity and uncontrollability of polymorphic self‐assembly behaviors and electronic processes at various length scales, alongside the ambiguous relationship between solution and solid states. Herein, precise control of multi‐level supramolecular self‐assembly of a polymorphic conjugated polymer, N‐PDPP4T‐HD with two distinct semi‐crystalline aggregated phases (β1 and β2) via solvent engineering is demonstrated. β1 forms 1D worm‐like nanostructures in solution, whereas β2 generates 2D nanoscale lamellar configuration, confirmed by experimental observation and molecular dynamic simulation. Such solution‐state features are inherited in the solid state (1D nanofibers for β1 and 2D granular‐like structures for β2). X‐ray characterizations reveal larger crystalline domains on the nanometer scale, reduced π‐stacking distance on the Ångstrom scale, and diminished paracrystallinity disorder for solid‐state β2. Going beyond conventional DC transistor characterizations, contact‐free ultrafast terahertz spectroscopy to unveil AC short‐range, intrinsic transport properties is employed. Longer charge carrier scattering time and thus intrinsic mobility of β2 result in threefold higher short‐range photoconductivity than β1. This work establishes the "solution structure – solid structure – local transport" relation in polymorphic conjugated polymers and provides new opportunities for high‐performance plastic electronic devices. [ABSTRACT FROM AUTHOR]

Aqueous two-phase systems (ATPS) can be described as an alternative to traditional liquid-liquid extraction systems, typically consisting of a polymer and a salt solution. An alternative polymer called polyvinylpyrrolidone (PVP) has emerged as a viable option for ATPS due to its low cost, stability, and potential. This study aimed to investigate the effect of the molecular weight of poly (vinylpyrrolidone) (PVP) (K17, K25, and K30) and the temperature (298.15, 303.15, and 308.15 K) in the system ATPSs composed of PVPs and sodium sulfate/potassium sulfate/tri sodium citrate. The tie-line data were determined by measuring the density (ρ) and refractive index (nD). Moreover, the phase compositions and plait point are investigated for different PVPs molecular weight, temperature, and salt type. In addition, the effect of these parameters on the binodal curve, tie-line length (TLL), and slope of tie line (STL) are analyzed in detail by comparing them with the literature data. The impact of the parameters on the binodal curves was investigated by utilizing the values of the effective excluded volume parameter (EEV) that were calculated from the LLE data. Furthermore, the binodal curves and the tie-line compositions were well-fitted by using some semi-empirical equations. The phase separation ability is enhanced with temperature and PVPs molecular weight. The modified UNIFAC-NRF is used to correlate the liquid-liquid equilibrium data of the studied systems and the optimized binary group interaction parameters were determined. [ABSTRACT FROM AUTHOR]

An anion-responsive boron-containing π-conjugated polymer was synthesized via the Sonogashira coupling polymerization. The 11B NMR, UV/vis absorption, and fluorescence spectra confirmed the formation of an anion complex between the polymer and tetrabutylammonium fluoride (TBAF). Thin films were then prepared either by the pre-addition method, where the thin film was prepared using a solution of the polymer and TBAF, or by the post-addition method, where the polymer thin film was treated with an aqueous TBAF solution. The contact angle measurements revealed an enhancement in wettability with both methods. Consequently, wettability can be controlled via anion-complex formation at the surface. [ABSTRACT FROM AUTHOR]

The dependency of molecular weight of polymer solutions at different concentrations has been studied using the Dynamic light scattering method. The correlation data were collected at two scattering angles 175° and 90° along with the 1 M NaCl solutions. Analysis shows the existence of two modes, namely, fast and slow, for all the solutions. Analyses of angle dependent study quantify the existence of homogeneity and heterogeneity in the solutions which results from the fact that when the separation of β value between aqueous and 1 M NaCl is very low, 1 M NaCl has almost no effect on the change in the hydrodynamic layer compared to the higher separation value of β when the same effect of 1 M NaCl was significantly observed. Further, analysis of correlation data suggests that with the increase in molecular weight and concentration of the polymer solutions, the homogeneity of the solutions increases decreasing its existing heterogeneity. These aspects of polymeric solutions are more prominently observed and further verified by comparing the results of aqueous and 1 M NaCl solutions. Interestingly, our result also shows an optimization method of homogeneity and heterogeneity by tuning molecular weight and concentrations in both aqueous and 1 M NaCl solutions. [ABSTRACT FROM AUTHOR]

Antimicrobial peptides (AMPs) are promising alternatives to traditional antibiotics for treating skin wound infections. Nonetheless, their short half‐life in biological environments restricts clinical applicability. Covalent immobilization of AMPs onto suitable substrates offers a comprehensive solution, creating contact‐killing surfaces with long‐term functionality. Here, a copolymer of poly[(hydroxy ethyl acrylamide)‐co‐(4‐benzophenone acrylamide)‐co‐(pentafluorophenyl acrylate)‐co‐(ECOSURF EH‐3 acrylate)], in short poly(HEAAm‐co‐BPAAm‐co‐PFPA‐co‐EH3A), is synthesized by free radical polymerization. Subsequent modification of active ester groups with the amine groups of SAAP‐148, results in a copolymer, that is non‐cytotoxic to human lung fibroblasts. UV photocrosslinking of the benzophenone units yields a polymer network that forms a hydrogel after swelling with aqueous medium. Both the SAAP‐148‐modified polymer in solution and the photocrosslinked hydrogels show good antimicrobial activity against strains of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii, including multidrug‐resistant strains, frequently found in wound infections. The covalent attachment of SAAP‐148 prevents leaching, ensuring sustained antimicrobial activity for at least 48 h in diluted human blood plasma and 14 days in PBS. This prolonged retention of antimicrobial activity in human blood plasma significantly enhances its clinical potential. Overall, this study shows the potential of the AMP‐functionalized photocrosslinkable polymer as antimicrobial wound dressings, providing an effective alternative to antibiotics. [ABSTRACT FROM AUTHOR]

Acrylamide polymers are typically used in industrial and healthcare sectors as thickening agents; however, their thickening capabilities rely mainly in their molecular mass. A versatile and simple strategy to improve their performance is the copolymerization with specific monomers or their chemical modification with structures like dendritic or hyperbranched molecules. This study introduces a novel acrylamide‐acrylic acid polymer grafted with minor proportions (≤4.0 wt%) of Boltorn H30, a hyperbranched polyester monomer. The incorporation of Boltorn H30 aims to exploit the hyperbranched architecture's impact on the viscosity and rheological behavior of polymer solutions. Polymers with 0.4 and 4.0 polyester wt% characterized by several analytical techniques displayed improved viscosity in aqueous solution compared against the parent poly(acrylamide‐co‐acrylic acid). Results revealed that while the molecular mass distribution changed between 20% and 94%, the thickening capabilities significantly improved with increments of 2.7 and 3.8 times compared to that of the original polymers. These findings demonstrate that even with a minimal incorporation of hyperbranched polyesters, the abundance of hydroxyl groups fosters extensive hydrogen bonding, resulting in enhanced viscosity properties of the polymer. [ABSTRACT FROM AUTHOR]

Industrial chemical producers and formulators are increasingly conscious of their responsibility in stewarding planetary resources and minimizing harm to the environment. In 2019, the Royal Society of Chemistry (RSC) engaged an industry task force from across the value chain to drive technical research to classify a new class of polymer—polymers in liquid formulation (PLFs). Building on this, the task force called for step change in sustainability practices for PLFs and instigated a design and development process to identify research themes and priorities that could accelerate innovation in this area. However, a key challenge was that as a novel classification, PLFs were largely unknown outside the chemistry community and entirely absent from the mainstream research agenda. To establish the demand-pull requirements of the value chain for sustainable PLFs, the RSC used a 'mission-oriented' innovation framework to enable the taskforce to co-design an ideal-type portfolio of research and innovation projects, and to set out a realistic roadmap for transition. This perspective article presents a summary of the activities carried out by the task force in its pursuit of mission-oriented innovation for PLFs and describes the strategic design method used to enable cross-value chain consensus on action for PLF sustainability, build system-wide innovation ecosystems and explore common-good scenarios. This article is part of the discussion meeting issue 'Green carbon for the chemical industry of the future'. [ABSTRACT FROM AUTHOR]

Polymeric mixed ionic–electronic conductors hold great potential for advancing high‐performance organic electronics due to their exceptional electrical conductivity achieved through ion–electron coupling. However, the widespread adoption of these conductors faces obstacles due to their reliance on environmentally harmful solvents during processing and the potential performance degradation under various conditions. In this study, a practical solution to these challenges is proposed by incorporating monomers with ionic liquid‐behaving pendant groups into conjugated polymers. The copolymerization of these charged monomers not only improves solubility in environmentally friendly solvents but also imparts long‐term stability against humidity, high temperatures, and mechanical deformation. The immobilized ion species foster highly selective interactions of these polymers with nitrogen dioxide, paving the way for the development of stretchable sensing devices capable of functioning at exceptionally high temperatures. [ABSTRACT FROM AUTHOR]

This study investigates the surface functionalization of plastic substrates through dip‐coating in azide‐functionalized polymer solutions, followed by a click reaction (i.e., strain‐promoted azide–alkyne cycloaddition). Acrylic, poly(ethylene terephthalate) (PET), and nylon substrates are dip‐coated with a series of polymers containing various azide groups grafted onto the poly(methyl methacrylate‐co‐hydroxyethyl methacrylate) backbone to examine structural effects on the surface density of clickable azide groups. X‐ray photoelectron spectroscopy and fluorescence spectroscopy confirm the subsequent click‐immobilization of cycloalkyne‐tagged fluorescein, which is quantified to calculate the surface density of clickable azide groups. Further investigations demonstrate that the surface density of azide groups can be controlled by manipulating the polymer ratio during dip‐coating, thus enabling the preparation of a linear surface gradient in terms of azide group density. Finally, the microcontact printing (µCP) method is employed to pattern the functionalized surfaces and quantify the functional molecules immobilized on the surface by µCP. This study highlights the adaptability of click chemistry and polymer coating techniques for the advanced functionalization of plastic surfaces for materials science and engineering applications. [ABSTRACT FROM AUTHOR]

Non‐covalent interactions offer an alternative way for developing stimulus‐responsive materials such as sensors, machines, and drug‐delivery systems. We recently reported that a urethane‐equipped tetrakis(porphyrin) forms one‐handed helical supramolecular polymers in solution in response to chirality of chiral solvents. Conformational changes in helical sense were detected using circular dichroism (CD) spectroscopy, which showed that the tetrakis(porphyrin) can possibly be used as a sensor for determining the enantiomeric excess of a chiral analyte. Hence, we studied the scope and limitations of the chiral‐induction behavior of tetrakis(porphyrin) to deepen the understanding of tetrakis(porphyrin)‐based chiral sensing systems. Herein, we report the chiral‐induction behavior of tetrakis(porphyrin) in various chiral solvents, which was found to be CD‐active in many chiral solvents. Notably, the tetrakis(porphyrin) was CD active in a cryptochiral molecular solvent, which is exciting because the chiralities of acyclic saturated hydrocarbons are hard to sense. Consequently, this study highlights the potential advantages of supramolecular chiral sensors capable of targeting a wide range of analytes, including molecules that are absorption‐silent in the UV/vis region, ones devoid of anchoring functional groups, and acyclic, saturated hydrocarbons. [ABSTRACT FROM AUTHOR]

Determination of a broad spectrum of analytes, carried out with analytical instruments in samples with complex matrices, including environmental, biological, and food samples, involves the development of new and selective sorption phases used in microextraction techniques that allow their isolation from the matrix. SPME solid-phase microextraction is compatible with green analytical chemistry among the sample preparation techniques, as it reduces the use of toxic organic solvents to the minimum necessary. Over the past two decades, it has undergone impressive progress, resulting in the development of the thin-film solid-phase microextraction technique, TF-SPME (the thin-film solid-phase microextraction), which is characterized by a much larger surface area of the sorption phase compared to that of the SPME fiber. TF-SPME devices, in the form of a mostly rectangular metal or polymer substrate onto which a thin film of sorption phase is applied, are characterized, among others, by a higher sorption capacity. In comparison with microextraction carried out on SPME fiber, they enable faster microextraction of analytes. The active phase on which analyte sorption occurs can be applied to the substrate through techniques such as dip coating, spin coating, electrospinning, rod coating, and spray coating. The dynamic development of materials chemistry makes it possible to use increasingly advanced materials as selective sorption phases in the TF-SPME technique: polymers, conducting polymers, molecularly imprinted polymers, organometallic frameworks, carbon nanomaterials, aptamers, polymeric ionic liquids, and deep eutectic solvents. Therefore, TF-SPME has been successfully used to prepare analytical samples to determine a broad spectrum of analytes in sample matrices: environmental, biological, and food. The work will be a review of the above-mentioned issues. [ABSTRACT FROM AUTHOR]

To solve the downhole problems correlated with clay hydration swelling and dispersion under high‐temperature conditions, a 1‐aminoethyl‐3‐vinylimidazolium bromide ([NVim]Br) and a [NVim]Br/acrylamide copolymer (poly([NVim]Br‐co‐AM)) are synthesized and used as inhibitors. The molecular structures of [NVim]Br and poly([NVim]Br‐co‐AM) are characterized by FT‐IR and 1H‐NMR. The inhibition properties of [NVim]Br and poly([NVim]Br‐co‐AM) are evaluated by free swelling and dispersion tests, linear swelling, hot roll recovery experiments and thermogravimetric analyses.The inhibition mechanisms were revealed by X‐ray diffraction, zeta potential, wettability analysis and ESEM observation. The results showed that both [NVim]Br and poly([NVim]Br‐co‐AM) has significantly superior inhibition performance compared with the common inhibitors KCl, polyether amine D230 and polyquaternium‐7. Both [NVim]Br and poly([NVim]Br‐co‐AM) can resist 250 °C. [NVim]Br performed excellently in inihibiting both crystalline and osmotic swelling, which depended on the strong electrostatic adsorption and hydrogen bonds of imidazole cations and primary amine in [NVim]+. Poly([NVim]Br‐co‐AM) exerted excellent inhibition by minimizing osmotic swelling, reducing hydrophilicity and increasing clay bonding. The results are important for understanding the rational design of novel efficient inhibitors for drilling high‐temperature shale formation. [ABSTRACT FROM AUTHOR]

This study analyzes the behavior of sodium polyacrylate (NaPA) as a rheological modifier for clay-based tailings. Special emphasis is placed on the impact of calcium and magnesium ions in industrial water, which are analyzed through rheograms, zeta potential measurements, and molecular dynamics simulations. The results are interpreted as electrostatic interactions, steric phenomena, and cation solvation. This interpretation integrates experimental studies with microscopic analyses, employing molecular dynamics simulations to elucidate the underlying mechanisms. In all cases, a decrease in the yield stress of synthetic slurries is observed as the dosing of NaPA increases due to greater repulsion between tailings particles through an increase in electrostatic repulsion and larger steric forces that hinder agglomeration. However, efficiency is reduced in the presence of divalent cations as zeta potential measurements suggest a reduction in the electrical charges of the particles and the polymer, making its application more challenging. The differences obtained in the presence of calcium compared to magnesium are explained in terms of the solvation of these ions and their impact on the polymer conformation in solution and adsorption on the mineral surfaces. This explanation is reinforced by molecular dynamics studies, which indicate that polymer adsorption on minerals depends on the type of mineral and type of ion. Particularly for quartz, the highest adsorption of NaPA occurs in the presence of calcium, whereas for a kaolinite surface, the highest polymer adsorption is obtained in the presence of magnesium. The competitive effect of these phenomena leads to the rheological behavior of the tailings being dominated by the effects originating in the clay. [ABSTRACT FROM AUTHOR]

We studied the properties of a reaction front that forms in irreversible reaction–diffusion systems with concentration-dependent diffusivities during the synthesis of polymer brushes. A coarse-grained model of the polymerization process during the formation of polymer brushes was designed and investigated for this purpose. In this model, a certain amount of initiator was placed on an impenetrable surface, and the "grafted from" procedure of polymerization was carried out. The system consisted of monomer molecules and growing chains. The obtained brush consisted of linear chains embedded in nodes of a face-centered cubic lattice with excluded volume interactions only. The simulations were carried out for high rafting densities of 0.1, 0.3, and 0.6 and for reaction probabilities of 0.02, 0.002, and 0.0002. Simulations were performed by means of the Monte Carlo method while employing the Dynamic Lattice Liquid model. Some universal behavior was found, i.e., irrespective of reaction rate and grafting density, the width of the reaction front as well as the height of the front show for long times the same scaling with respect to time. During the formation of the polymer layer despite the observed difference in dispersion of chain lengths for different grafting densities and reaction rates at a given layer height, the quality of the polymer layer does not seem to depend on these parameters. [ABSTRACT FROM AUTHOR]

The preparation of core–sheath fibers by electrospinning is a topic of significant interest for producing composite fibers with distinct core and sheath functionalities. Moreover, in core–sheath fibers, low-molecular-weight substances or nanosized inorganic additives can be deposited in a targeted manner within the core or the sheath. Commonly, for obtaining a core–sheath structure, coaxial electrospinning is used. It requires a coaxial spinneret and suitable immiscible solvents for the inner and outer solutions. The single-nozzle spinneret electrospinning of emulsions can address these issues, but use of a stabilizing agent is needed. A third approach—preparation of core–sheath fibers by single-nozzle spinneret electrospinning of homogeneous blend solutions of two polymers or of a polymer/low-molecular-weight substance—has been much less studied. It circumvents the difficulties associated with the coaxial and the emulsion electrospinning and is thoroughly discussed in this review. The formation of core–sheath fibers in this case is attributed to phase-separation-driven self-organization during the electrospinning process. Some possibilities for obtaining core–double sheath fibers using the same method are also indicated. The gained knowledge on potential applications of core–sheath fibers prepared by single-nozzle spinneret electrospinning of emulsions and homogeneous blend solutions is also discussed. [ABSTRACT FROM AUTHOR]

Based on the two-fluid model, we successfully simulated the film casting process of the polymer solution system and observed the unique response wave of the film thickness and the concentration via applying perturbation. We identify that this instability pattern is essentially the product under the coupling effect of viscoelastic stress and osmotic pressure from fluctuations on different scales, which causes it to exhibit biperiodic characteristics. We call this new instability mode known as dual-mode draw resonance instability. Among them, the concentration oscillation predominates, thereby limiting the critical draw ratio Drc of the system. Through sorting out the molecular image of the polymer concentration response to perturbation, the relevant parameters are extracted, and the law of their influence on the Drc further verifies our conclusion and provides guidance for actual production. [ABSTRACT FROM AUTHOR]

In this work, a framework for deriving theoretical equations for mean squared displacement (MSD) and fractional Fokker–Planck is developed for any arbitrary rheological model. The obtained general results are then specified for different fractional rheological models. To test the novel equations extracted from our framework and bridge the gap between microrheology and fractional rheological models, microrheology of polystyrene in tetrahydrofuran solutions at several polymer concentrations is measured. By comparing the experimental and theoretical MSDs, we find the fractional rheological parameters and demonstrate for the first time that the polymer concentration regimes can be distinguished using the fractional exponent and relaxation time data because of the existence of a distinct behavior in each regime. We suggest simple approximations for the critical overlap concentration and the shear viscosity of viscoelastic liquidlike solutions. This work provides a more sensitive approach for distinguishing different polymer concentration regimes and measuring the critical overlap concentration and shear viscosity of polymeric solutions, which is useful when conventional rheological characterization methods are unreliable due to the volatility and low viscosity of the samples. [ABSTRACT FROM AUTHOR]

Oil displacing agents used in oil drilling and extraction can improve crude oil recovery. Acrylamide polymers were the most common oil displacing agents because of their high viscosity and low cost. However, conventional acrylamide polymers were susceptible to hydrolysis and thermal degradation in harsh reservoir conditions. Unique physical and chemical properties of nanoparticles promise to improve the performance of acrylamide polymers in harsh reservoir conditions. In this paper, the nano-micron copolymers of acrylamide (AM), 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS), and modified nano-silica (M-SiO2) were synthesized by two methods: aqueous solution polymerization and inverse emulsion polymerization, named W-PAAGS and E-PAAGS, respectively. The characterization was studied by Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TG), particle size analysis, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The thickening ability, temperature resistance, salt resistance, and thermal stability of the two polymers synthesized were studied. The results showed that E-PAAGS had a better thickening ability than W-PAAGS. The viscosity of the E-PAAGS solution was much higher than that of the W-PAAGS solution at polymer concentrations above 5000 mg/L. The temperature and salt resistance of E-PAAGS was also better than that of the W-PAAGS. In addition, E-PAAGS exhibits better aging stability. After 30 days of aging, E-PAAGS had 71.3% viscosity retention whereas only 52.7% retention was observed for W-PAAGS, and the viscosity of E-PAAGS was always higher than that of W-PAAGS. The significant difference properties of W-PAAGS and E-PAAGS was due to the differences in copolymer structure caused by the different polymerization methods. [ABSTRACT FROM AUTHOR]

The aim of this paper is to determine the structure of a post irradiated polymer aqueous solution in semi-dilute regime concentration. The neutral polymer, polyvinylpyrrolidone of molar mass Mw = 1.300.000 g/mol was treated by γ-irradiation with different doses ranged from 0.8 to 50 kGy. The post irradiated polymer, PVP*, is dissolved in water and viscosity measurements are performed at 25 °C. The Mark–Houwink–Sakurada and the Flory exponents, are deduced and solvent qualities are determined. An extension of the blob model theory is reported and correspondent structural parameters are defined. For all the used doses the structure of the solution are determined and discussed. The relative variation of the correlation length,τ [ξ ∗ (D)], versus the received dose by the polymer. [ABSTRACT FROM AUTHOR]

The main purpose of this study was to investigate effects of various electrospinning parameters on the morphology and diameter of cellulose nanofibril (CNF) filled polylactide (PLA) nanofibers. For this purpose, first of all effects of three important electrospinning parameters; polymer solution concentration, solution feeding rate and collector distance to feeding tip were studied. Then, effects of using higher amount of CNF, effects of using cellulose nanocrystal (CNC) particles, and effects of adding potassium chloride salt were also investigated. It was observed that when optimum electrospinning parameters were determined, then it was possible to obtain almost "bead-free" morphology and "finest" average diameter of 232 nm for PLA/CNF electrospun fibers. Increasing values of feeding rate and collector distance parameters resulted in bead formation and thicker diameters. On the other hand, increasing CNF amount, using CNC particles and adding KCl salt, all resulted in further decreases in the diameter down to 152 nm; mainly due to increased charge density of the polymer solution. Moreover, in vitro degradation analysis of all types of electrospun nanofiber mats in a simulated body fluid revealed that increasing the immersion period increased their degradation rate in terms of "% weight loss". It was also observed that, mats with fine diameter fibers had higher degradation rate. [ABSTRACT FROM AUTHOR]

Electrochemical impedance spectroscopy (EIS) was employed in an attempt to gain insight into the mechanisms of ethyl 2-cyanoacrylate (ECA) curing (polymerisation) and bonding on aluminium alloy 2024 metal. EIS can detect ionic movement, adsorption processes, charge transfer and storage occurring at an adhesive/substrate interface and/or in a bulk bond line during curing. Low-frequency capacitance measurements demonstrated sensitivity to surface polymerisation reactions and were modelled using an equivalent circuit model with two time constants in series. At a frequency of 1 kHz, changes in the dielectric polymer could be readily followed with time, confirmed by employing a crown ether to accelerate the polymerisation process. Hydrolytic degradation of poly-ECA bonds at a stainless steel interface was also investigated. An equivalent circuit model containing a number of circuit components comprising pore, charge transfer and diffusional impedances, along with polymer film, double layer and diffusional capacitances (represented by constant phase elements), was developed. Three regions were identified in the frequency domain and ascribed to processes taking place at the polymer/electrolyte and polymer/metal oxide interfaces. In short, EIS can be employed to follow the rate of polymerisation of ethyl-2-cyanoacrylate and also the degradation of the resulting polymer in saline solution. [ABSTRACT FROM AUTHOR]

[Display omitted] Atmospheric water harvesting through reticular materials is an innovation that has the potential to change the world. Here, this study offers a technique for creating a solar-powered hygroscopic polymer material for atmospheric water harvesting with the reticular materials. The results show that the porous hygroscopic polymer materials can achieve high performance with high vapor capture (up to ac. 28.8–49.7 mg/g at 28–38 %RH and 25 ℃), rapid photothermal conversion efficiency (up to 32.2 ℃ within 15 min under 1000 W/m−2 light at 25 ℃), a low desorption temperature (lower than 40 ℃), and an effective water release rate. Besides, the material also has excellent water-retention properties, which can effectively store desorbed liquid water in polymer networks for use by vegetation during water demand periods. The strategy opens new avenues for atmospheric water-harvesting materials, which will hopefully solve the global crisis of freshwater shortages. [ABSTRACT FROM AUTHOR]

The relationship between the mechanical, electrical, and morphological properties of annealed films based on short-side-chain perfluorinated sulfonic acid ionomer (SSCI) with an Aquivion structure was systematically investigated using dynamic mechanical analysis (DMA), small-angle X-ray scattering (SAXS), and impedance spectroscopy. Annealing the membranes at temperatures of 140, 150, and 160 °C—above the glass transition temperature of SSCI—and the nature of the liquid phase in the polymer dispersion significantly influence the structural parameters of the membranes, specifically the size of the conductive channels formed by hydrophilic sulfonic acid groups. SAXS and AFM analyses revealed that membranes cast from N,N-dimethylacetamide (DMAA) exhibit a denser, less structured morphology, resulting in lower hydrogen permeability (φ = 4.6 ± 0.7 nmol/m/s/MPa), comparable to the commercial Nafion 211 membrane (φ = 6.5 nmol/m/s/MPa), but with significantly lower proton conductivity (35 ± 5 mS/cm) than Nafion 211 (95 mS/cm). In contrast, membranes obtained from a water-alcohol mixture showed a well-defined structure (SAXS, AFM), with proton conductivity values ranging from 70 to 103 mS/cm, comparable to Nafion 211. However, the hydrogen permeability of these membranes varied significantly depending on the annealing conditions (φ = 5.5–65.3 nmol/m/s/MPa). SAXS data indicated that the membranes had a similar degree of crystallinity (11–13%) but differed in the positions of the ionomer peak and matrix knee, which are associated with variations in the size of the conductive channels and account for the observed differences in ionic conductivity. Membranes annealed at 150 °C, which exhibited hydrogen permeability and ionic conductivity values close to those of the commercial Nafion 211 membrane, were used to fabricate membrane electrode assemblies (MEA). The electrochemical characteristics of these MEAs were investigated at 30 and 60 °C, 100% relative humidity, at both atmospheric pressure and 200 kPa overpressure. At a current density of 1.75 A/cm2, the fabricated membranes demonstrated power outputs of up to 550 and 950 mW/cm2, which are comparable to, and even exceed, those of the commercial Nafion 211 membrane (700 mW/cm2). However, despite the high-power performance, significant membrane degradation was observed after 10,000 cycles in durability tests. These findings contribute to a better understanding of the relationship between the electrochemical properties and the structure of short-side-chain perfluorinated sulfonic acid ionomers with an Aquivion-type structure and are expected to enhance their application in fuel cells. [Display omitted] • The effect of annealing temperature on PFSA films properties has been studied. • Films based on dispersion ROH/H 2 O and DMAA differ in ionic conductivity. • MEA based on films annealed at 150 °C shown power density up to 950 mW/cm2. [ABSTRACT FROM AUTHOR]

The solid phase extraction of Au, Ir, Pd, Pt, and Rh on a polymer gel modified with ionic liquid containing methylimidazolium groups (MIA-PG) has been investigated. The positively charged surface of the sorbent is highly suitable for the sorption of stable chlorido complexes of the studied analytes, while the retention of base metals Cu, Fe, Ni, Zn, and Mn is negligible. Optimization experiments performed showed that, at 0.05 M HCl, the degree of sorption of Au, Ir, Pd, and Pt is above 95%, and only for Rh, the maximum degree is 65%; complete elution is achieved in the mixture of thiourea in HCl. The results obtained from the equilibrium adsorption studies are fitted in various adsorption models, such as Langmuir and Freundlich, and the model parameters have been evaluated. The kinetics analysis indicated that the adsorption of Au, Ir, Pd, Pt, and Rh onto the sorbent follows the pseudo-second-order model. Intraparticle diffusion and ion exchange reactions were the rate-limiting steps. Analytical procedures were developed for Pd, Pt, and Rh determination in road dust and soil and for Au determination in copper ore and copper concentrate. The procedures are validated by the analysis of certified reference materials. Analytical figures of merit confirmed their applicability in routine laboratory practice. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) possess intrinsically broad emission spectra, making them suitable for modulating high‐quality white light‐emitting diodes (WLEDs). However, the chief technical challenge in applying CDs to WLEDs is the aggregation‐caused quenching (ACQ) effect. A common solution is polymer post‐modification on the surface of CDs, which is a low‐yield, hard‐to‐purified, and complicated process. Herein, polymerized CDs with broad emission (full width at half maxima, FWHM = 187 nm) are synthesized via a one‐step solvothermal method. The obtained polymerized CDs display excellent solution‐processed and film‐forming capabilities, with absolute photoluminescence quantum yield as high as 4.7% in thin film state, creating a firm foundation for assembling solution‐processed WLEDs. Moreover, the polymerization steps of CDs are analyzed and described in detail. The polymer chains prevent ACQ and create new energy levels, resulting in the broad emission of CDs in an aggregated state. Subsequently, WLEDs are fabricated using polymerized CDs as the single active emitting material. The optimal device achieves the maximum brightness of 337.50 cd m−2 and FWHM of 242 nm, covering nearly the entire visible spectral window. The results present a new approach to obtaining polymerized CDs and further fabricating WLED with a straightforward, cost‐effective method. [ABSTRACT FROM AUTHOR]

Although the layer‐by‐layer (LBL) processing can usually achieve an optimal bulk‐heterojunction morphology for high‐performance Organic photovoltaics (OPVs), the unambiguous working principles governing the morphology evolution are still lacking. To address this issue, here the phase‐separation kinetics of LBL processing are comprehensively studied using in situ spectroscopies, which are very sensitive to the intermolecular interactions, e.g. the molecular packing and D:A phase‐separation. Upon casting the nonfullerene acceptor (i.e., the BTP‐eC9) solution on top of the polymer donor, i.e., PM6, it is found that 1) the solvent will first swell the polymer and induce a polymer gel, 2) following the polymer gelation, the NFAs will immediately permeate into the cavities of polymer gel and form a molecular‐level D:A mixing, and 3) with the evaporation of the solvent, phase‐separation between the donor and acceptor occurs and results in a bulk‐heterojunction morphology as those achieved with blend‐cast processing. With these understandings, more diverse processing conditions have been purposely utilized to dictate the phase evolution process precisely. As a result, a high efficiency of 19.7% is reached, representing one of the best among binary OPVs. Therefore, this work deciphers phase‐separation kinetics of LBL processing and should pave the way toward advanced morphology control for high‐performance OPVs. [ABSTRACT FROM AUTHOR]

Objectives: The study aimed to investigate the effect of different polymers and plasticizers on oral disintegrating films (ODFs) containing triamcinolone acetonide (TA), a glucocorticosteroid indicated for the treatment of oral wounds. Materials and Methods: Thirteen different formulations with the same amount of polymer and plasticizer were prepared by solvent casting. Briefly, the solutions containing polymer, plasticizer, and other ingredients were poured into Petri dishes and kept at room temperature for 20 hours to obtain ODFs. Physical properties of ODFs such as visual appearance, weight and thickness uniformity, pH, mechanical durability (tensile strength, elongation at break and folded insurance), and disintegration time were assessed and drug content analysis was performed on ODFs. Results: Suitable ODFs were produced with hydroxypropyl methylcellulose (HPMC), polyvinyl alcohol, carboxymethylcellulose, gelatin, and pectin, while film integrity was not achieved with polyethyleneglycol 4000 (PEG 4000), chitosan and starch. Glycerin made ODFs more transparent, reduced their thickness, and improved their mechanical properties. On the other hand, PEG 400 reduced the weight variation. Regarding drug content, PEG-containing gelatin-based ODF (ODF10) and pectin-based ODF (ODF12) complied with pharmacopeial limits. In addition, all ODFs except HPMC-based ODFs had an appropriate pH range. Conclusion: When all features were evaluated together in terms of the applicability of an ODF to the patient, the most convenient formulation was found to be gelatin-based with PEG 400 ODF (ODF10). In short, patients will benefit from ease of application and transportation and effective therapy with correct dosing with the development of ODF forms of TA for which there are no preparations except for cream, gel, and pomade forms for topical use in Türkiye. [ABSTRACT FROM AUTHOR]

Fracturing operations can effectively improve the production of low-permeable reservoirs. The performance of fracturing fluids directly affects the fracturing efficiency and back flow capacity. As polymerbased fracturing fluids (such as guar gum (GG), polyacrylamide (HPAM), etc.) are high-viscosity fluids formed by viscosifiers and crosslinking agents, the degree of gel breakage after the fracturing operation directly influences the damage degree to the reservoir matrix and the mobility of oil angd gas produced from the reservoir into the wellbore. This study compared the viscosity, molecular weight, and particle size of the fracturing fluid after gel breakage prepared by GG and HPAM as viscosifiers, as well as evaluate their damage to the core. Results show that the viscosities of the gel-breaking fluid increased with the concentration of the viscosifier for both the HPAM-based and GG-based fracturing fluids. For the breaking fluid with the same viscosity, the molecular weight in the HPAM-based gel-breaking fluid was much larger than that in the GG-based system. Moreover, for the gel-breaking fluid with the same viscosity, the molecular particle size of the residual polymers in the HPAM-based system was smaller than that in the GG-based system. The damage to the core with the permeability of 1 × 10-3 μm² caused by both the HPAM-based and GG-based gel-breaking fluids decreased with the increase in the solution viscosity. For the gel-breaking fluid systems with the same viscosity (i.e., 2-4 mPa s), the damage of HPAM-based fracturing fluid to low-permeability cores was greater than the GG-based fracturing fluid (45.6%e80.2%) since it had a smaller molecular particle size, ranging from 66.2% to 77.0%. This paper proposed that the damage caused by hydraulic fracturing in rock cores was related to the partilce size of residual polymers in gel-breaking solution, rather than its molecular weight. It was helpful for screening and optimizing viscosifiers used in hydraulic fracturing process. [ABSTRACT FROM AUTHOR]

In this study, the wall shear stress in the channel flow of polyacrylamide polymers was investigated through electrochemical experiments, and the effects of the polymer concentration were evaluated at different Reynolds numbers. The objective was to explore the relationship between the changes in the drag reduction and near-wall turbulence structure induced by the polymer. The experiments were conducted using polymer concentrations of 0, 20, 50, 100, and 150 ppm, and a drag reduction of approximately 23% was achieved at a bulk Reynolds number of R e b = 18 750. In the electrochemical method, the working electrode was arranged spanwise, and simultaneous measurements were performed for eight electrodes to discuss the scale of the near-wall low-speed streaks and burst events. A comprehensive analysis of the correlation of the wall shear stress in the streamwise direction and the cross-spectrum of two points in the spanwise direction revealed that large streamwise and spanwise scales of near-wall low-speed streaks were generated at high polymer concentrations. Furthermore, the results obtained using the variable interval time averaging technique indicated that polymer incorporation suppressed the wall shear stress fluctuations and weakened both the intensity and frequency of the bursting events. [ABSTRACT FROM AUTHOR]

Detecting the flow regimes of Newtonian turbulence (NT), elasto-inertial filament (EIF), elasto-inertial turbulence (EIT), and maximum drag reduction (MDR) of polymer solution and their transition has been a hot topic in the last decade. We attempted to detect NT, EIF, EIT, and MDR by visualizing vortex shedding downstream of an array of cylinders that was inserted perpendicular to polymer-doped two-dimensional (2D) flow. Since polymers are stretched at the cylinders, the consequent vortex shedding is affected by viscoelasticity. The flow regimes are characterized based on Weissenberg (Wi) and Reynolds numbers (Re) with the relaxation time of the polymeric solution estimated from capillary-thinning experiments. The flow regimes are observed for different molecular weights of polyethylene oxide and polyacrylamide in solution and are categorized as either vortex type 1, type 2, and type 3 on a Re–Wi map based on flow visualization using particle image velocimetry. In addition, turbulent statistics of these flow regimes are calculated to more fully quantify these flow regimes. We found that vortex types from 1 to 3 have a similarity to NT, EIF, EIT, and MDR. In addition, characteristic turbulent energy transfer without an increase in turbulent energy production was found in the flow regimes of vortex types 2 and 3 of each polymer solution. Our results suggest intriguing parallels between pipe, jet, and 2D turbulent flow for drag-reducing polymeric solutions. [ABSTRACT FROM AUTHOR]

The novelty of this work is in its prediction of the non-Newtonian behavior of polymeric liquids in the orthogonal superposition of small-amplitude oscillatory shear flow upon steady shear flow. We do so using rotarance theory, namely, by considering only the orientability of the macromolecules in suspension. We arrive at explicit analytical solutions for the complex viscosity as a function of the steady shear rate and of the frequency of the superposed oscillation. Our results explain the canonical laboratory observations of orthogonal superposition: (α) the real part of the complex viscosity as a function of frequency decreases with increasing steady shear rate, (β) the curves of minus the imaginary part as a function of frequency go through a maximum, and (γ) the independence of the steady mean shear stress from the superposed oscillation. We compare our predictions with those of parallel superposition and discover that the further the macromolecular structure from axisymmetric, I 3 / I 1 = 1 , the greater the difference between parallel and superposition. In other words, studying both directions of superposition of either part of the complex viscosity uncovers the most important feature of macromolecular structure, the moment ratio, I 3 / I 1 , and thus, the macromolecular orientability. [ABSTRACT FROM AUTHOR]

Background: The combination of multiple polymers is anticipated to serve as a means to diversify the physical properties and functionalities of dissolving microneedles. The mixing state of components is considered as a crucial factor in determining their suitability. Objectives: The purpose of this study was to elucidate whether thermal analysis of frozen aqueous solutions can appropriately predict the miscibility of hyaluronic acid (HA) and other polymers used for dissolving microneedles prepared by a micromolding method. Methods: Aliquots of aqueous polymer solutions were applied for thermal analysis by heating the samples from −70 °C at 5 °C/min to obtain the transition temperature of amorphous polymers and/or the crystallization/melting peaks of polymers (e.g., polyethylene glycol (PEG)). Films and dissolving microneedles were prepared by air-drying of the aqueous polymer solutions to assess the polymer miscibility in the solids. Results: The frozen aqueous single-solute HA solutions exhibited a clear Tg′ (the glass transition temperature of maximally freeze-concentrated solutes) at approximately −20 °C. The combination of HA with several polymers (e.g., dextran FP40, DEAE-dextran, dextran sulfate, and gelatin) showed a single Tg′ transition at temperatures that shifted according to their mass ratio, which strongly suggested the mixing of the freeze-concentrated solutes. By contrast, the observation of two Tg′ transitions in a scan strongly suggested the separation of HA and polyvinylpyrrolidone (PVP) or HA and polyacrylic acid (PAA) into different freeze-concentrated phases, each of which was rich in an amorphous polymer. The combination of HA and PEG exhibited the individual physical changes of the polymers. The polymer combinations that showed phase separation in the frozen solution formed opaque films and microneedles upon their preparation by air-drying. Coacervation occurring in certain polymer combinations was also suggested as a factor contributing to the formation of cloudy films. Conclusions: Freezing aqueous polymer solutions creates a highly concentrated polymer environment that mimics the matrix of dissolving microneedles prepared through air drying. This study demonstrated that thermal analysis of the frozen solution offers insights into the mixing state of condensed polymers, which can be useful for predicting the physical properties of microneedles. [ABSTRACT FROM AUTHOR]

The detailed systematic study of aqueous polyacrylamide solutions at different concentrations and different molar concentrations of NaCl solutions along with the dependency at scattering angles 175o and 90o has been performed rigorously using the Dynamic Light Scattering method. Aqueous polymer solutions of different concentrations of polymer as well as at different molar concentrations of NaCl solutions were prepared for the study. Analyses of the correlation functions show the presence of three concentration regions consisting each with the presence of fast and slow modes. Out of three, the one (unentangled semidilute) concentration regime shows the unique morphology of polymer solutions irrespective of the change in polymer concentrations and with the change in NaCl concentrations. Furthermore, the angular dependency results show the presence of amount of heterogeneity of polymer chains in the solutions which quantified from the overall change of stretching parameter of slow mode β (Dilute and entangled region ~ 20%, Unentangled region ~ 7%). [ABSTRACT FROM AUTHOR]

The room temperature ionic liquid trihexyl(tetradecyl)phosphonium decanoate ([P66614][Dec]) was employed in the liquid-liquid extraction of Co(II) from hydrochloric acid solutions in the presence of Ni(II). The extraction performance in liquid-liquid separations showed a strong dependence on the acid content of the feed aqueous solution. The best performance in terms of extracted cobalt and selectivity was obtained when the feed contained a HCl concentration above 6 M On the contrary, when the experiment was performed in absence of HCl, a lower extraction and Co/Ni selectivity were obtained. This behavior has been rationalized by considering the protonation of the [Dec]− anion and the different Co(II)/Ni(II) speciation in HCl media. Moreover, polymer inclusion membranes (PIMs) were prepared using PVC and [P66614][Dec] at different weight rations. Only the PIM formulated with a 30:70/PVC:[P66614][Dec] weight ratio demonstrated effective extraction of Co(II) from the HCl solution. The extraction efficiency and selectivity of the PIM was comparable to that from biphasic liquid experiments at 8 M HCl. The results of this study constitute a promising background for further practical developments of carboxylate-based ILs applied in Co/Ni separations. [ABSTRACT FROM AUTHOR]