Search

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]

The simulation of polymer solutions often requires the development of methods that accurately include hydrodynamic interactions. Resolution on the atomistic scale is too computationally expensive to cover mesoscopic time and length scales on which the interesting polymer phenomena are observed. Therefore, coarse-graining methods have to be applied. In this work, the solvent is simulated using the well-established multi-particle collision dynamics scheme, and for the polymer, different coarse-graining methods are employed and compared against the monomer resolved Kremer–Grest model by their resulting diffusion coefficients. This research builds on previous work [Ruiz-Franco et al., J. Chem. Phys. 151, 074902 (2019)], in which star polymers and linear chains in a solvent were simulated and two different coarse-graining methods were developed, in order to increase computational efficiency. The present work extends this approach to ring polymers and seeks to refine one of the authors' proposed model: the penetrable soft colloid model. It was found that both proposed models are not well suited to ring polymers; however, the introduction of a factor to the PSC model delivers satisfying results for the diffusion behavior by regulating the interaction intensity with the solvent. [ABSTRACT FROM AUTHOR]

We used equilibrium and non-equilibrium atomistic simulations to probe the influence of anion chemistry on the true conductivity, dynamical correlations, and ion transport mechanisms in polymeric ionic liquids. An inverse correlation was found between anion self-diffusivities, ionic mobilities, and the anion size for spherical anions. While some larger asymmetric anions had higher diffusivities than smaller spherical anions, their diffusivities and mobilities did not exhibit a direct correlation to the anion volumes. The conductivity and anion dynamical correlations also followed the same trends as displayed by the diffusivity and mobility of anions. All the systems we examined displayed positively correlated motion among anions, suggesting a contribution that enhances the conductivity beyond the ideal Nernst–Einstein value. Analysis of ion transport mechanisms demonstrated very similar hopping characteristics among the spherical anions despite differences in their sizes. [ABSTRACT FROM AUTHOR]

Understanding the nucleation behavior of water in dilute polymeric solutions is quintessential for the development of suitable artificial ice recrystallization inhibition (IRI) agents. Although poly(vinyl alcohol) (PVA) is found to be one of the most potent biomimetic IRI agents, the molecular understanding of the nucleation behavior of water in the presence of PVA is still lacking. Here, we use molecular dynamics to elucidate the role of concentration, degree of supercooling, degree of polymerization, and amphiphilicity of PVA and PVA-like polymers on the homogeneous nucleation of water in dilute polymeric solutions using the seeding method. Using classical nucleation theory (CNT), our simulations indicate an increase in the chemical potential difference between ice and melt that favors ice nucleation. However, it also predicts a significant increase in the ice–melt interfacial energy that impedes nucleation. The relative increase in the interfacial energy dominates the increase in the chemical potential difference, which results in a decrease in the nucleation rate of water with an increase in the solute concentration. This study contradicts the previous simulation study that suggested the promotion of homogeneous ice nucleation by PVA and supports the experimental observations of the heterogeneous origins of ice nucleation. Our results also suggest the non-classical origins of ice nucleation in polymeric solutions and the limitation of the CNT in predicting heterogeneous ice nucleation in polymeric solutions. [ABSTRACT FROM AUTHOR]

In this paper, we announce the public release of a massively parallel, graphics processing unit (GPU)-accelerated software, which is the first to combine both coarse-grained particle simulations and field-theoretic simulations in one simulation package. MATILDA.FT (Mesoscale, Accelerated, Theoretically Informed, Langevin, Dissipative particle dynamics, and Field Theory) was designed from the ground-up to run on CUDA-enabled GPUs with Thrust library acceleration, enabling it to harness the possibility of massive parallelism to efficiently simulate systems on a mesoscopic scale. It has been used to model a variety of systems, from polymer solutions and nanoparticle-polymer interfaces to coarse-grained peptide models and liquid crystals. MATILDA.FT is written in CUDA/C++ and is object oriented, making its source-code easy to understand and extend. Here, we present an overview of the currently available features, and the logic of parallel algorithms and methods. We provide the necessary theoretical background and present examples of systems simulated using MATILDA.FT as the simulation engine. The source code, along with the documentation, additional tools, and examples, can be found on the GitHub MATILDA.FT repository. [ABSTRACT FROM AUTHOR]

We report the first-ever complete measurement of MAOStress material functions, which reveal that stress can be more fundamental than strain or strain rate for understanding linearity limits as a function of Deborah number. The material used is a canonical viscoelastic liquid with a single dominant relaxation time: polyvinyl alcohol (PVA) polymer solution cross-linked with tetrahydroborate (Borax) solution. We outline experimental limit lines and their dependence on geometry and test conditions. These MAOStress measurements enable us to observe the frequency dependence of the weakly nonlinear deviation as a function of stress amplitude. The observed features of MAOStress material functions are distinctly simpler than MAOStrain, where the frequency dependence is much more dramatic. The strain-stiffening transient network model was used to derive a model-informed normalization of the nonlinear material functions that accounts for their scaling with linear material properties. Moreover, we compare the frequency dependence of the critical stress, strain, and strain-rate for the linearity limit, which are rigorously computed from the MAOStress and MAOStrain material functions. While critical strain and strain-rate change by orders of magnitude throughout the Deborah number range, critical stress changes by a factor of about 2, showing that stress is a more fundamental measure of nonlinearity strength. This work extends the experimental accessibility of the weakly nonlinear regime to stress-controlled instruments and deformations, which reveal material physics beyond linear viscoelasticity but at conditions that are accessible to theory and detailed simulation. [ABSTRACT FROM AUTHOR]

A systematic experimental density and sound velocity measurement was carried out for imidazolium-based ionic liquids (ILs) in pure water and in aqueous solutions of 0.03 w/w of water-miscible polymers with different structures and molar masses at T= (288.15, 293.15, 298.15, 303.15 and 308.15) K and p = 84.5 kPa. The ILs under investigation are 1-butyl-3-methylimidazolium hydrogen sulphate ([C4mim][HSO4]) and 1-butyl-3-methylimidazolium bromide ([C4mim]Br). The effects of temperature, polymer type, and IL anion type on the various volumetric and compressibility properties, such as apparent molar volume, isentropic compressibility, apparent molar isentropic compressibility, and infinite dilution apparent molar properties for transfer of ILs from water to aqueous polymer solution were scrutinised. From the gathered results, ion-water interactions, ion-ion interactions at finite concentration, and water-structure breaking character for aqueous solutions of [C4mim][HSO4] are more considerable than aqueous solutions of [C4mim]Br. However, [C4mim]Br-polymer interactions are more favourable than interactions between [C4mim][HSO4] and the studied polymers. [ABSTRACT FROM AUTHOR]

The structural, optical and acoustical properties of a polymer composite of sodium sulfate (Na2SO4) doped polyvinyl pyrrolidone (PVP) were studied. The simple chemical route method was utilized for the preparation of the polymer composite by varying the concentration of Na ions in the PVP. The pure 3% PVP solution was mixed with five different concentrations of Na2SO4 solutions in the ratio of 80:20. X-ray diffraction (XRD) spectra of PVP/Na2SO4 (1.0% of Na2SO4 in 3.0% of PVP) confirmed the crystalline nature of the PVP/Na2SO4 polymer composite. The identification of several chemical functional groups contained in the PVP/Na2SO4 was demonstrated by Fourier transform infrared (FTIR) spectroscopy. The FTIR showed the excellent interaction between the polymer (PVP) and the dopant Na2SO4. Optical studies were performed by utilizing a UV-visible absorbance spectrophotometer. The UV-VIS spectroscopy results indicated that absorption increased in an asymmetric manner and the absorption peak showed a red shift with increasing Na ions concentration in the host PVP. The optical band gaps (direct and indirect) were found to decrease with increase in Na ions concentration in the polymer due to increase in the density of localized states in the band-gap. The activation and Urbach energies were evaluated from the conductivity measurements and the absorption coefficient, respectively. Several acoustical parameters, viz. ultrasonic velocity, density, viscosity, adiabatic compressibility, intermolecular free length, acoustic impedance, and surface tension, were also computed. The ultrasonic velocity, acoustic impedance, density, viscosity, and surface tension of the polymer solutions were found to increase while the adiabatic compressibility and intermolecular free length decreased with the addition of increasing amounts of Na ions in PVP. [ABSTRACT FROM AUTHOR]

π‐Conjugated polyfluorenes (PPs) comprising 2,3‐diaminobenzene‐1,4‐diyl (unit A) and 9,9‐dihexylfluorene‐2,7‐diyl (polymer‐1) or 9,9‐bis(6‐N,N,N,‐trimethylammoniumhexyl)fluorene‐2,7‐diyl (unit B) (polymer‐2) units were synthesized using Suzuki‐Miyaura coupling polycondensation. To compare the chemical properties and functionality of polymer‐2, a water‐soluble PP comprising benzene‐1,4‐diyl and unit B (polymer‐3) was synthesized. Polymer‐1 exhibited solvatochromism: the photoluminescence (PL) peak of the polymer in solutions shifted to a longer wavelength with an increase in the dielectric constants of solvents. Polymer‐1 formed charge transfer (CT) complexes with organic electron acceptors. The CT complexation behavior was systematically elucidated by the PL measurements using Stern–Volmer and Benesi–Hildebrand methods. Water‐soluble polymer‐2 could be used as a sensor for the chain length of telomere DNA by monitoring the changes in its PL intensity upon the addition of the analyte. The DNA sensing performance of polymer‐2 surpassed that of polymer‐3, attributed to the presence of unit A in polymer‐2. This unit brought polymer‐2 closer to DNA through hydrogen bonding between the amino group of polymer‐2 and nucleic acids in DNA. This interaction facilitated the occurrence of CT from the polymer backbone to DNA. [ABSTRACT FROM AUTHOR]

AbstractWith 2-acrylamido-2-methylpropanesulfonic acid (AMPS), YX-1 (a monomer containing an amide group) as the main chain, DX-2 (a monomer containing a hydrophobic group), N-vinylpyrrolidone (NVP) as the side chain, the high temperature resistant suspension stabilizer for spacer was prepared by free radical aqueous solution polymerization and characterized. The structure was characterized by fourier transform infrared (FTIR) spectroscopy and thermogravimetry-differential thermal analysis (TG-DTA), which proved that the synthesized product was the target product. The performance of the copolymer was evaluated. The experimental results showed that it could be used in the spacer fluid at 30 ∼ 210 °C, and its sedimentation performance could also meet the requirements in the spacer fluid system containing saturated brine. In order to explore the mechanism of the polymer, the polymer solution was tested by six-speed rotational viscometer, pyrene fluorescence probe test, environmental scanning electron microscopy (ESEM) test, and the isolation solution containing the copolymer was tested by Zeta potential test and X-ray diffraction (XRD). Based on the above test results, it is shown that the suspension stabilizer synthesized in this paper has the characteristics of thickening, physical plugging, chemical and physical adsorption, which can effectively ensure that the spacer fluid has excellent suspension performance at high temperature. [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 article demonstrates a mathematical model and theoretical analysis of the Micropolar fluid in the reverse roll coating process. It is important because micropolar fluids account for the microstructure and microrotation of particles within the fluid. These characteristics are significant for accurately describing the behavior of complex fluids such as polymer solutions, biological fluids, and colloidal suspensions. First, we modeled the flow equations using basic laws of fluid dynamics. The flow equations are made modified using low Reynolds number theory. The simplified equations are solved analytically. The exact expression for velocity and pressure gradient are obtained, while pressure is calculated numerically using Simpson Rule. Graphical depictions are carried out to comprehend the impact of the newly emerged physical constraints. The influence of micropolar and microrotation parameters on the velocity, pressure and pressure gradient are elaborated with the help of different graphs. [ABSTRACT FROM AUTHOR]

Hydrogels are of interest for a wide range of applications. The ability to control when the hydrogel degrades can provide beneficial properties such as controlled degradation in the environment or the stimulated release of drugs or cells. Self‐immolative polymers are a class of degradable polymers that undergo complete end‐to‐end depolymerization upon the application of a stimulus. They have been explored for hydrogel development, but the ability to prepare and selectively degrade self‐immolative hydrogels under neutral aqueous conditions has so far been limited. We describe here the preparation of water‐soluble polyglyoxylamides with cross‐linkable pendent azides and their cross‐linking to form hydrogels with 4‐arm poly(ethylene glycol)s having unstrained and strained alkynes using copper‐assisted and strain‐promoted azide‐alkyne click chemistry respectively. The influence of pendent azide density and solution polymer content on the resulting hydrogels was evaluated. A polyglyoxylamide with a 70 : 30 ratio of pendent hydroxyl:azide successfully provided hydrogels with compressive moduli ranging from 1.3–6.3 kPa under copper‐free conditions at 10–20 % (w/w) of polymer in phosphate‐buffered saline. Selective depolymerization and degradation of the hydrogels upon irradiation with light was demonstrated, resulting in reductions in the compressive moduli and the release of depolymerization products that were detected by NMR spectroscopy. [ABSTRACT FROM AUTHOR]

In this study, the ionic liquid (IL) trioctylmethylammonium salicylate (TOMAS) was prepared and incorporated into a polymer inclusion membrane (PIM) based on cellulose triacetate (CTA) as the polymer for the removal of Cr(VI). Various parameters including the effect of membrane composition (plasticizer and carrier concentration) as well as variables affecting both the feed phase and receiving solution have been investigated. Optimal results were achieved with a PIM made of 50% CTA and 50% TOMAS (% in mass) without the addition of any plasticizer. Using this PIM, Cr(VI) was effectively transported from a feed solution consisting of 10 mg L−1 Cr(VI) in 0.01 mol L−1 NaNO3 at pH = 2, to a receiving solution containing 0.1 mol L−1 NaOH. The transport of Cr(VI) was not affected by the presence of other metals, such as Cr(III), Cd(II), Zn(II), Cu(II), and Ni(II), and a selective recovery rate of 93.61% for both single-ion and mixed-ion solutions after 24 h of processing was obtained. Finally, the stability of the membrane was also investigated, with a slight decrease in efficiency observed after 5 days of reuse. [ABSTRACT FROM AUTHOR]

Partially hydrolyzed polyacrylamide is extensively utilized in enhanced oil recovery operations. However, its efficacy is compromised by mechanical degradation during transport through injection lines, valves, and reservoir, which leads to a reduction in the average molecular weight, diminishing the solution's viscosity and viscoelastic properties, critical for efficient oil displacement. In this investigation, we characterized the degree of mechanical degradation in HPAM solutions by evaluating shear and extensional rheological parameters preand post‐degradation. Mechanical degradation was induced by subjecting them to controlled flow through a valve featuring varying degrees of constriction and flow rates. Our results demonstrate a significant reduction in zero‐shear viscosity and high‐strain extensional viscosity of mechanically degraded solutions, with reductions of up to 64%. To mitigate this issue, we explored the incorporation of silica nanoparticles as a potential remedy for mechanical degradation. These nanoparticles strengthen the network structure of HPAM, thereby reducing its susceptibility to mechanical degradation. Our findings reveal that shear and extensional viscosities of mechanically degraded NPs‐HPAM solutions experienced only minimal reductions, dropping to 12% and 0%, respectively. This underscores the effectiveness of the nanoparticle‐enhanced HPAM solutions in preserving viscosity and viscoelasticity under mechanical stress, presenting a promising avenue for improving the robustness of EOR processes. [ABSTRACT FROM AUTHOR]

In the advancement of organic photovoltaics (OPV) toward scale‐up production, how to mitigate the batch instability of electron‐donating polymers originated from varied molecular weights remains a great challenge. By taking into consideration the relationship between the molecular weight of electron‐donating polymers and the relevant critical concentration (c*) of the solution, herein it is demonstrated that the aggregation behavior of the electron‐donating polymers can be tailored through manipulating c* of the polymer solution. It is interesting to note that the excessive aggregation in low‐molecular‐weight fractions can be circumvented while the favorable mixing ratio can be identified. By preparing the binary bulk heterojunction film under c*‐defined conditions for mixed‐molecular‐weight polymers, a notable power conversion efficiency of 19.1% for binary devices is achieved. Of particular importance is that a linear interrelation can be established between the c* for the maximum PCE and c* for the low‐molecular‐weight fraction aggregation, validating those straightforward spectra measurements can accurately and rationally guide the molecular weight mixing of photovoltaic donor polymers, thereby fully harnessing the potent driving force and affinity inherent to the low‐molecular‐weight fractions. These findings offer a straightforward and logical framework for addressing batch variability in the large‐scale production of high‐performance OPV devices. [ABSTRACT FROM AUTHOR]

Mechanical stress governs the dynamics of viscoelastic polymer systems and supercooled glass-forming fluids. It was recently established that liquids with long terminal relaxation times are characterized by transiently frozen stress fields, which, moreover, exhibit long-range correlations contributing to the dynamically heterogeneous nature of such systems. Recent studies show that stress correlations and relaxation elastic moduli are intimately related in isotropic viscoelastic systems. However, the origin of these relations (involving spatially resolved material relaxation functions) is non-trivial: some relations are based on the fluctuation-dissipation theorem (FDT), while others involve approximations. Generalizing our recent results on 2D systems, we here rigorously derive three exact FDT relations (already established in our recent investigations and, partially, in classical studies) between spatio-temporal stress correlations and generalized relaxation moduli, and a couple of new exact relations. We also derive several new approximate relations valid in the hydrodynamic regime, taking into account the effects of thermal conductivity and composition fluctuations for arbitrary space dimension. One approximate relation was heuristically obtained in our previous studies and verified using our extended simulation data on two-dimensional (2D) glass-forming systems. As a result, we provide the means to obtain, in any spatial dimension, all stress-correlation functions in terms of relaxation moduli and vice versa. The new approximate relations are tested using simulation data on 2D systems of polydisperse Lennard–Jones particles. [ABSTRACT FROM AUTHOR]

Shear thickening fluids (STFs) have garnered attention as potential enhancers of protective capabilities and for the optimization of Kevlar® armor design. To assess the possible shear thickening properties and potential application in ballistic protection, ten formulations were developed by employing polyethylene glycol (PEG) or polypropylene glycol (PPG), along with fumed silica or Aerosil HDK®. Rheological characterization facilitated the identification of formulations displaying shear thickening behavior. The potential integration of the selected shear thickening fluids (STFs) into Kevlar®-based composites was investigated by studying the impact resistance of Kevlar® soft armor structures. Also, high-velocity impact testing revealed that the distance between aramid layers plays a crucial role in the impact resistance effectiveness of Kevlar®–STF composite structures and that there is a very narrow domain between optimal and undesired scenarios in which STF could facilitate the penetration of Kevlar. The introduction of STF between the Kevlar sheets disrupted this packing and the energy absorption capacity of the material was not improved. Only one formulation (PEG400, Aerosil 27 wt.%) led to a less profound traumatic imprint and stopped the bullet when it was placed between layers no.1 and no.2 from a total of 11 layers of Kevlar XP. These experimental findings align with the modeling and simulation of Kevlar®–STF composites using Ansys simulation software (Ansys® AutoDyn 2022 R2). [ABSTRACT FROM AUTHOR]

Controlling the extensional rheological properties of solutions is of great interest for a number of applications, such as printing and coatings, as polymeric additives can modify a fluid's droplet size, formation, and breakup. We have measured the extensional flows of polyacrylamide graft poly(ethylene glycol) amine (PAM‐g‐PEGa) solutions as a function of grafting density. PAM‐g‐PEGa is synthesized with grafting densities of 2.5%, 5.5%, 8%, and 30% and extensional flow was analyzed with drop‐on‐substrate rheology. Flow time scales and profiles are then compared to understand the effects of backbone extension from the addition of side chains. At low grafting densities, the viscous friction from the added side chains is comparable to, and in some cases, counteracts the losses in extensibility to the graft polymer's backbone, leading to increases in the relaxation time of the polymer. At higher grafting densities, the extension of the backbone reduces the relaxation time. By characterizing the effects of the graft density architecture on extensional flows, we are able to fine‐tune and control the breakup dynamics of elastic solutions. [ABSTRACT FROM AUTHOR]

The new generation of impact-resistant materials should be lightweight and flexible. For this purpose, various additives, such as shear thickening gels (STG) are synthesized and incorporated into these materials. In this article, it has been tried to develop a new method for synthesizing new shear -thickening gels (n-STG). This new method involves dispersing Polyvinyl alcohol (PVA) solution into the STG polymer matrix. Unlike previous studies that used PDMS, and boric acid as fixed materials in the preparation of STG, this work introduces PVA as a new auxiliary material in the PDMS and boric acid polymer matrix. At first, different percentages of PVA solution in distilled water (DW) were prepared. After a series of experiments, PVA (14%) was well combined with the polymer matrix. In this way, by changing the mass ratio of PVA (14%) to pyroboric acid (P-BA) and PVA (14%) to polydimethylsiloxane (PDMS), 7 values of (1:6) to (7:6) were tested. When the ratio of PVA (14%) to P-BA is greater than 1:6, it lacks STG properties. However, when the ratio of PVA (14%) to PDMS changed from 1:6 to 6:6, shear thickening gel properties were observed and the samples were named n-STG. The maximum shear storage modulus (G'max) of n-STG samples first increases and then decreases, reaching a maximum value of 0.55 MPa. The resilience elasticity test demonstrated that the rebound percentage value of the n-STG-5 sample was 22.6% higher than the STG sample without PVA, due to its higher shear storage modulus. This study showed that PVA in the STG polymer matrix improves polymer chain cross-linking and performance due to its n-STG stimulus–response property. [ABSTRACT FROM AUTHOR]

It is imperative to develop high-efficiency polymer electrolytes to advance energy storage technologies. The goal of this research is to use the exceptional properties of ionic liquids such as their superior ionic conductivity, thermal stability, and adjustable physical and chemical characteristics to improve polymer electrolytes through doping. This study explores the incorporation of ionic liquids into polymer matrices to create novel ionic-liquid-doped polymer electrolytes (ILDPEs). We synthesized a ILDPEs using Poly(ethyl methacrylate) (PEMA) as the host polymer with salt sodium iodide (NaI) doped with a new ionic liquid (1-hexyl-3-methylimidazolium iodide) synthesized using solution cast technique. Impedance spectroscopy revealed that doping ionic liquid enhances the ionic conductivity of the PEMA + NaI complex. Ionic conductivity significantly increased upon the addition of the ionic liquid (IL), reaching a maximum value of 7.7 × 10–4 S/cm at room temperature. The ionic transference number (tion) for the polymer electrolyte with the highest ionic conductivity was calculated using Wagner polarization method while electrochemical stability window was calculated by linear Sweep Voltammetry. The crystalline nature of the ILDPEs films was studied using Polarizing Optical Microscopy (POM). To confirm the complex formation and bonding structure, Fourier-transform infrared spectroscopy (FTIR) and X-Ray Diffraction (XRD) were also employed. Finally, dye-synthesized solar cell (DSSC) and electric double-layer capacitor (EDLC) were fabricated using the highest ionic conducting polymer electrolytes. [ABSTRACT FROM AUTHOR]

Monte Carlo simulations of isotropic solutions of double‐stranded DNA (deoxyribonucleic acid) are performed using the well‐established oxDNA model. By comparing the fluctuation amplitudes with theoretical predictions, the parameters of a generic macroscopic model of an isotropic linear polymer solution/melt are determined. A multiscale continuum field model is thus obtained, corresponding to the full specificity of the isotropic phase of double‐stranded DNA in the usual B‐form as perceived at the macroscopic level. Present research is particularly focused on the coupling between spatial concentration/density variations of the polymer and the emerging nematic orientation order of the chains. This rather unfamiliar, only recently described phenomenon, inherent to linear polymers, is outlined and interpreted. Quantitative predictions are provided for the degree of nematic order induced by concentration gradients in isotropic solutions of double‐stranded DNA. [ABSTRACT FROM AUTHOR]

Polymer microparticle synthesis based on the surface‐templated method is a simple and environmentally friendly method to produce various microparticles. Unique particles with different compositions can be fabricated by simply annealing a polymer on a liquid‐repellent surface. However, there are hurdles to producing particles of homogeneous sizes with large quantities and varying the shape of particles. Here, a new approach to synthesizing multiple polymer microparticles using micropatterns with wettability contrast is presented. Polymer microparticles are formed in two steps. First, a layer of poly(sodium‐4‐styrenesulfonate) is deposited on the hydrophilic regions by dipping and withdrawing this micropattern from a polymer solution, and an array of microdroplets is formed. A dewetting‐inducing layer on the pattern is introduced, and then target polymer patches are sequentially generated on it. By annealing over Tg, the contact line of the target polymer patch is freely receded, creating a particle form. The size and shape of the microparticle can be controlled by varying the micropatterns. In addition, it is demonstrated that microparticles made of polymer blends or polymer/nanoparticle composite are easily produced. This versatile method offers the potential of surface‐templated synthesis to tailor polymer microparticles with different sizes, shapes, and functionalities in various research and applications. [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]

The widespread use of polymers has made our lives increasingly convenient by offering a more convenient and dependable material. However, the challenge of efficiently decomposing these materials has resulted in a surge of polymer waste, posing environment and health risk. Currently, landfill and incineration treatment approaches have notable shortcomings, prompting a shift towards more eco-friendly and sustainable biodegradation approaches. Biodegradation primarily relies on microorganisms, with research focusing on both solitary bacterial strain and multi-strain communities for polymer biodegradation. Furthermore, directed evolution and rational design of enzyme have significantly contributed to the polymer biodegradation process. However, previous reviews often undervaluing the role of multi-strain communities. In this review, we assess the current state of these three significant fields of research, provide practical solutions to issues with polymer biodegradation, and outline potential future directions for the subject. Ultimately, biodegradation, whether facilitated by single bacteria, multi-strain communities, or engineered enzymes, now represents the most effective method for managing waste polymers. [ABSTRACT FROM AUTHOR]

Gel‐spinning of ultra‐high molecular weight polyethylene (UHMWPE) fibers has attracted great interest in academia and industry since its birth and commercialization in the 1980s, due to unique properties such as high modulus, low density, and excellent chemical resistance. However, the high viscosity and long relaxation time greatly complicate processing. In industry, solvents, like decalin and paraffin oil, usually disentangle the physical networks and promote final drawability. From extruding the polymer solution to post‐solid‐stretching, many polymer physics problems that accompany high‐modulus fiber gel‐spinning should be understood and addressed. In this review, by detailed discussions about the effect of entanglements and intracrystalline chain dynamics on the mechanical properties of UHMWPE, theoretical descriptions of the structure formation of disentangled UHMWPE crystals, and the origin of high modulus and strength of final fibers are provided. Several physical intrinsic key factors are also discussed, revealing why UHMWPE is an ideal material for producing high‐performance fibers. [ABSTRACT FROM AUTHOR]

The utility of polymers in the fabrication of nanofibres via electrospinning is well established. Paramount to their application is understanding of their thermal properties, as these dictate not only their processability but also their mechanical robustness, stability under elevated temperatures, and suitability for intended applications. The electrospinning process, which involves heating polymers and subjecting them to high voltage, inherently modifies their thermal characteristics. This study attempts to elucidate these alterations, particularly by focusing on polyacrylonitrile (PAN) nanofibres. Employing techniques such as thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC), the study compares the thermal properties of electrospun PAN nanofibre mats with those of their virgin counterparts. The PAN nanofibres were synthesised by electrospinning the PAN polymer solution and collecting the resultant mat on a flat plate collector. For a comparative analysis, virgin PAN, from which nanofibres were derived, underwent identical thermal testing. The findings reveal a reduction in the glass transition temperature of PAN nanofibres by approximately 3–5 % compared to virgin PAN. In addition, a significant reduction in heat capacity of about 42 % was observed in the nanofibres. Additionally, the TGA results indicated solvent evaporation at approximately 110 °C. Therefore, this investigation sheds light on the nuanced alterations in the thermal characteristics of PAN nanofibre mats as a result of the electrospinning process, providing vital insights for their application in various thermal management scenarios. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulations were applied to investigate the formation of P84 polyimide membranes through the non‐solvent induced phase separation (NIPS) process, considering two scenarios: one using a conventional organic solvent like n‐methyl‐2‐pyrrolidone (NMP) and the other a greener alternative, γ‐butyrolactone (GBL), with water serving as the non‐solvent. Different compositions of polymer solutions were established along the binodal boundaries of the respective systems, derived from experimental cloud point data on the ternary phase diagram. The resulting polymer membranes were analyzed and compared in terms of their morphology. The wettability of their surfaces was notably affected by the polymer content in the initial casting solution and demonstrated a correlation with the Brunauer–Emmet–Teller (BET) specific surface area of the associated polymer nanostructures. The GBL solvent systems produced porous polymers qualitatively similar to those obtained with NMP, albeit with slightly narrower pore size distributions. [ABSTRACT FROM AUTHOR]

Background: The use of Polysulfone (PSf) as membrane material for dialysis therapy is becoming more common. However, the PSf membrane can cause the adsorption of blood proteins followed by the adhesion of platelets, destruction of red blood cells, and thrombus formation. One of the biggest challenges in creating membranes for hemodialysis (HD) applications is ensuring biocompatibility. Therefore, to maintain the biocompatibility of PSf membranes, further modifications are necessary. Methods: In this study, the performance and biocompatibility of PSf membranes were improved by the impregnation of TiO2‐hydroxyapatite composite as an additive. The TiO2‐hydroxyapatite composite was first synthesized via sintering at 1200°C, and then a dope solution composed of pristine PSf polymer solution in N‐Methyl‐2‐pyrrolidone solvent (NMP) and different wt% ratios of the synthesized composite were prepared, and resultant membranes were fabricated using a film applicator via a phase inversion scheme using water as a non‐solvent exchange medium. The synthesized composite was characterized using SEM, EDX, and XRD techniques. Results: The FTIR analysis confirmed the weak interaction of PSf polymer with the hydroxyapatite moiety of the composite. The interaction of the synthesized composite within the membrane matrix was evaluated via leaching ratio results. The hydrophilicity, pore profile, and pure water permeation flux rates were also determined. The results of the biocompatibility study showed that membranes based on TiO2‐hydroxyapatite composite had reduced adsorption of BSA protein by 34.41% as well as less than 5% hemolysis ratio. Additionally, the study displayed thrombus formation ranging from 2.08% to 8.69%, respectively. The dialysis results indicated that compared with the original PSf membrane, the TiO2‐hydroxyapatite composite showed high clearance rates for urea (73.81%) and creatinine (72.13%) solutes, respectively. Conclusion: Therefore, blending TiO2‐hydroxyapatite composite in the PSf membrane significantly improved the biocompatibility and removal ability of uremic solutes. [ABSTRACT FROM AUTHOR]

In this work, a series of thermosensitive ionic liquid functionalized polymers, PNx(IL)y, with controllable morphology and particle size were prepared by free radical polymerization. Then, using the polymer PN64(IL)8 with uniform morphology as a templating agent, the ZnO composite photocatalytic materials doped with rare earth metal Ce were prepared in combination with a microwave-assisted and templated hydrothermal reaction method. Series different Ce-doping amount photocatalytic materials ZnO-Ce-x‰ were characterized by XRD, SEM, TEM, XPS, and other methods. The results demonstrated that the templated materials PN64(IL)8 can prepare ZnO-Ce-2‰ with uniform petaloid ambulacra shape, good distribution of elements, and excellent photocatalytic performance. Photocatalytic degradation experiments of methyl orange (MO) showed that when the Ce-doping amount is only 2‰, the degradation rate of organic dyes can reach 96.5% by reacting the photocatalytic materials in water for 1 h. In addition, this kind of photocatalyst can be used for the degradation of high-concentration MO, as well as being easily recovered and effectively reused by simple filtration. Therefore, the structure of this kind of photocatalyst is controllable in the preparation process with an extremely low Ce-doping amount compared with current reports, and it has a good application prospect in the field of wastewater treatment technology. [ABSTRACT FROM AUTHOR]

With the gradual miniaturization of electronic devices and the increasing interest in wearable devices, flexible microelectronics is being actively studied. Owing to the limitations of existing battery systems corresponding to miniaturization, there is a need for flexible alternative power sources. Accordingly, energy harvesting from surrounding environmental systems using fluorinated polymers with piezoelectric properties has received significant attention. Among them, polyvinylidene fluoride (PVDF) and PVDF co-polymers have been researched as representative organo-piezoelectric materials because of their excellent piezoelectric properties, mechanical flexibility, thermal stability, and light weight. Electrospinning is an effective method for fabricating nanofibrous meshes with superior surface-to-volume ratios from polymer solutions. During electrospinning, the polymer solution is subjected to mechanical stretching and in situ poling, corresponding to an external strong electric field. Consequently, the fraction of the piezoelectric β-phase in PVDF can be improved by the electrospinning process, and enhanced harvesting output can be realized. An overview of electrospun piezoelectric fibrous meshes composed of PVDF or PVDF co-polymers to be utilized is presented, and the recent progress in enhancement methods for harvesting output, such as fiber alignment, doping with various nanofillers, and coaxial fibers, is discussed. Additionally, other applications of these meshes as sensors are reviewed. [ABSTRACT FROM AUTHOR]

As temperature and salt-resistant materials, hydrophobically associating polymers can form a reversible spatial network structure through the interaction between their hydrophobic groups, effectively improve the viscosity of the polymer solution through association, and enhance the temperature and salt resistance of the polymer. Hydrophobically associating monomers have different effects on the properties of polymer solutions. Herein, acrylic acid, acrylamide, and 2-acrylamido-2-methylpropanesulfonic acid were used as hydrophilic monomers. The three hydrophobic monomers with different carbon chain lengths were prepared by the bromination reaction. Hydrophobic associating polymers DQM1-PAM, DQM2-PAM, and DQM3-PAM were prepared by aqueous solution free-radical polymerization. The structure–activity relationship of the hydrophobic monomers with different carbon chain lengths on polymers was studied. It was confirmed by Fourier-transform infrared spectroscopy and 1H-NMR that the target product was successfully synthesized. Scanning electron microscopy revealed that with increasing hydrophobic carbon chain length, the hydrophobic microarea of molecular aggregation increased, forming a closer spatial network structure. Thermogravimetric and fluorescence tests revealed that with increasing hydrophobic carbon chain length of polymer molecules, the polymerization temperature resistance increased, intermolecular association degree increased, and critical association concentration decreased. Rheological property evaluation revealed that the viscosity of 0.5% polymer DQM1-PAM, DQM2-PAM, and DQM3-PAM was 71.32, 100.21, and 118.79 mPa·s after shearing at 120 °C and 170 s−1 for 1 h. With the increase in the carbon chain length, the retention rate of shear viscosity of polymer in a salt solution increased, showing good salt resistance. Concurrently, the molecular aggregation microarea of a solution with 0.5% polymer, degree of molecular chain action, viscoelasticity of the solution (G' > G''), and thixotropic area all increased. The performance of polymer solution can be improved by modifying hydrophobically associating polymers with long carbon chains, which has a broader application. [ABSTRACT FROM AUTHOR]

New amphiphilic block copolymers on based benzylmethacrylates or 2,3,4,5,6-pentafluorobenzyl methacrylate and N-isopropylacrylamide with high yields (89–94%) and MM 1.2∙105 and 1.63∙105 were synthesized. The relative constants of chain transfer to tris-(pentafluorophenyl)germanium during the radical polymerization of 2,3,4,5,6-pentafluorobenzyl methacrylate and benzylmethacrylate were 1.26 and 0.45, respectively. The structure of the copolymers was confirmed by IR and NMR spectroscopy. By the method of TGA analysis, the temperature of the beginning of decomposition of polymers was established, which amounted to 228.2 ºC and 150 ºC for the fluorinated and non-fluorinated block copolymer, respectively. The properties of polymers in solutions were studied by GPC, molecular hydrodynamics and optics. For both fluorinated and non-fluorinated samples, only macromolecules were observed in dilute solutions. The behavior of a non-fluorinated sample was well described as a coil in a good solvent, while fluorinated macromolecules were characterized by a compressed coil conformation, due to the presence of fluorine in the polymer structure. It was shown that the block copolymers formed stable Langmuir monolayers with high surface pressures (50–58 mN/m), and the transferred Langmuir–Blodgett films on silicon wafers were hydrophilic (water contact angles are 68–73 ºC). A large hysteresis loop on the surface pressure isotherm obtained under compression-expansion conditions for a fluorinated block copolymer indicates significant inter- and intramolecular interactions at the water–air interface. [ABSTRACT FROM AUTHOR]

Every year, contaminated water is responsible for over one million deaths globally. Microbiology leads other fields in the development of solutions to water contamination to reduce these deaths while advancing the achievement of SDG 6, which aims to ensure universal access to water and sanitation. This article explores hydrogel polymers as a solution to water contamination through microbial control. Using a systematic approach, this study collects, reviews, analyzes, and synthesizes the findings of studies on the structure, properties, and mechanisms used by hydrogel polymers in pathogen control in water systems, emphasizing recent advances in microbiology that have improved the antimicrobial properties of hydrogel polymers, enhanced their synthetic properties, and improved their overall ability to control the spread of pathogens in water. Other additional notable findings, including the applications of hydrogel polymers in water systems, the environmental implications of using the method to decontaminate and purify water for various purposes, and the regulatory standards needed to reinforce the viability and effectiveness of the adaptation of hydrogel polymers for the control of harmful or unwanted microorganisms in water systems, inform the presented inferences on the future of hydrogel technologies and new opportunities for the expansion of their commercial use. [ABSTRACT FROM AUTHOR]

Herein, we report an efficient and facile strategy for the preparation of imidazolium-based ionic liquid (IL) monomers ([CnVIm][Br], n = 2, 4, 6, 8, 10, and 12) and their corresponding polymeric ionic liquids (PILs) with potent antimicrobial activities against Gram-negative and Gram-positive bacteria and fungi. The electrospinning technique was utilized to tailor the polymers with the highest antimicrobial potency into porous membranes that can be easily implemented into diverse systems and extend their practical bactericidal application. The antimicrobial mechanism of obtained ILs, polymers, and nanomaterials is considered concerning the bearing chain length, polymerization process, and applied processing technique that provides a unique fibrous structure. The structure composition was selected due to the well-established inherent amphiphilicity that 1-alkylimidazolium ILs possess, coupled with proven antimicrobial, antiseptic, and antifungal behavior. The customizable nature of ILs and PILs complemented with electrospinning is exploited for the development of innovative antimicrobial performances born from the intrinsic polymer itself, offering solutions to the increasing challenge of bacterial resistance. This study opens up new prospects toward designer membranes providing a complete route in their designing and revolutionizing the approach of fabricating multi-functional systems with tunable physicochemical, surface properties, and interesting morphology. [ABSTRACT FROM AUTHOR]

Wearable and self‐healing soft electronics have led to a significant emphasis on their potential in creating versatile, conformable, and sustainable electronic modules. Among conductive additives, Liquid metals (LMs), combining both solid and liquid characteristics, have gained widespread attention due to their versatile physical, chemical, and electrical properties as well as self‐healing capability, biocompatibility, and recyclability. The fluidity of LMs facilitates adaptability to various experimental conditions and components for specific applications. Moreover, the oxide shell on LMs exhibits strong compatibility with surface functionalization and polymerization processes, enhancing the development of reliable composite materials. Herein, an in‐depth analysis of the fundamental properties and characteristics of LMs while addressing their current drawbacks, such as unpredictable reactivity and poor surface stability, is presented. To harness the advantages of LMs, their integration is extensively discussed with polymeric materials through various grafting strategies, leading to the development of macromolecular composites with exceptional softness, solubility, surface functionalization, and versatility. Furthermore, the applications of LMs within LM‐elastomer composites, particularly focusing on their relevance in specific fields such as flexible electronics, are investigated. Finally, LMs' future prospects are emphasized by highlighting their compatibility with self‐healing polymers, thereby providing pathways for major breakthroughs of LMs based devices. [ABSTRACT FROM AUTHOR]

The mechanism of the development of solutal Marangoni instability in a thin layer of polymer solution, by rapid evaporation of volatile solvent, is studied numerically. By considering the conservation of mass, momentum, and concentration across the evaporating surface, physically reliable kinematic and boundary conditions are derived and implemented in numerical simulations. To simulate the drying of a polymer solution more realistically up to the point where 80% of solvent was evaporated, the concentration-dependent evaporation rate, viscosity, and diffusivity and the movement of the interface are taken into account. Numerical simulations demonstrate that the generation and merging of convective cell motions in a layer during drying lead to surface patterns as the drying process continues. The drying of a polymer film and the development of the surface topography including thickness deviation depend on various physical phenomena such as Marangoni stress, surface tension, vapor recoil pressure, evaporation rate, initial concentration of polymer, and variation of viscosity and diffusivity with concentration. Meanwhile, the vapor recoil force plays little role in the onset of instability motion and the irregularity of the evaporation surface. Furthermore, both the diffusivity reduction and the viscosity thickening due to evaporative concentration play a critical role in the formation of the skin layer, because they suppress the Marangoni instability motion and therefore impede the convective transport of concentrated polymeric solute. [ABSTRACT FROM AUTHOR]

The power of a macromolecular theory for the transport properties of a polymeric liquid increases with the number of analytical expressions for its most important material functions. In this work, we add another of these canonical function to our recent series of material function derivations for rotarance theory. By rotarance theory, we mean the explanation of the elasticity of polymeric liquids by use of (i) the diffusion equation to get the orientation distribution in Euler coordinates, and (ii) the integration in phase space using this distribution to get the target material function. In this paper, we target parallel superposition of oscillatory shear flow upon steady shear flow. We arrive at analytical expressions for both parts of the complex viscosity in parallel superposition. We find that these explain the classic experimental observations in parallel superposition: (a) the maximum in the real part of the complex viscosity, and (b) the negative values of minus its imaginary part, and (c) the independence of the steady mean shear stress from the superposed oscillation. [ABSTRACT FROM AUTHOR]

Flexible polymers exhibit pronounced drag reduction but weak resistance to mechanical shear, whereas rigid polymers exhibit remarkable resistance to mechanical shear but slightly weaker drag reduction. Therefore, mixing flexible and rigid polymers could offer improvements in comprehensive drag-reduction performance. This letter reports an experimental study on the drag-reduction performance of binary polyacrylamide (PAM) and xanthan gum (XG) solutions with the PAM concentration fixed at 10 ppm. From comparing curves of the drag reduction rate vs Reynolds number and shearing time, 70-ppm XG is the optimal choice for forming a binary polymer solution with 10-ppm PAM. This binary solution also offers drag-reduction effects equivalent to those of a pure 50-ppm PAM solution. Although it decreases with time, the synergistic coefficient still remains much larger than zero. This implies that the positive synergistic effect of the PAM–XG binary solution persists even under long-term shearing. These results offer a fundamental basis for developing high-performance polymer drag reducers. [ABSTRACT FROM AUTHOR]

Hydrogel materials based on sodium alginate find versatile applications in regenerative medicine and tissue engineering due to their unique properties, such as biocompatibility and biodegradability, and the possibility of the customization of their mechanical properties, such as in terms of the individual requirements of separate clinical applications. These materials, however, have numerous limitations in the area of biological activity. In order to eliminate their limitations, sodium alginate is popularly applied in combination with added gelatin, which represents a product of collagen hydrolysis. Despite numerous beneficial biological properties, matrix materials based on gelatin have poor mechanical properties and are characterized by their ability for rapid degradation in an aqueous environment, particularly at the physiological temperature of the body, which significantly limits the independent application opportunities of this type of composition in the range of scaffolding production dedicated for tissue engineering. Collagen hydrogels, unlike gelatin, are characterized by higher bioactivity, dictated by a greater number of ligands that allow for cell adhesion, as well as better stability under physiological conditions. Fish-derived collagen provides a material that may be efficiently extracted without the risk of mammalian prion infection and can be used in all patients without religious restrictions. Considering the numerous advantages of collagen indicating its superiority over gelatin, within the framework of this study, the compositions of hydrogel materials based on sodium alginate and fish collagen in different concentrations were developed. Prepared hydrogel materials were compared with the properties of a typical composition of alginate with the addition of gelatin. The rheological, mechanical, and physicochemical properties of the developed polymer compositions were evaluated. The first trials of 3D printing by extrusion technique using the analyzed polymer solutions were also conducted. The results obtained indicate that replacing gelatin with fish collagen at an analogous concentration leads to obtaining materials with a lower swelling degree, better mechanical properties, higher stability, limited release kinetics of calcium ions cross-linking the alginate matrix, a slowed process of protein release under physiological conditions, and the possibility of extrusion 3D printing. The conducted analysis highlights that the optimization of the applied concentrations of fish collagen additives to composition based on sodium alginate creates the possibility of designing materials with appropriate mechanical and rheological properties and degradation kinetics adjusted to the requirements of specific applications, leading to the prospective opportunity to produce materials capable of mimicking the properties of relevant soft tissues. Thanks to its excellent bioactivity and lower-than-gelatin viscosity of the polymer solution, fish collagen also provides a prospective solution for applications in the field of 3D bioprinting. [ABSTRACT FROM AUTHOR]

Stem cell-based therapy holds promise for cartilage regeneration in treating knee osteoarthritis (KOA). Injectable hydrogels have been developed to mimic the extracellular matrix (ECM) and facilitate stem cell growth, proliferation, and differentiation. However, these hydrogels face limitations such as poor mechanical strength, inadequate biocompatibility, and suboptimal biodegradability, collectively hindering their effectiveness in cartilage regeneration. This study introduces an injectable, biodegradable, and self-healing hydrogel composed of chitosan–PEG and PEG–dialdehyde for stem cell delivery. This hydrogel can form in situ by blending two polymer solutions through injection at physiological temperature, encapsulating human adipose-derived stem cells (hADSCs) during the gelation process. Featuring a 3D porous structure with large pore size, optimal mechanical properties, biodegradability, easy injectability, and rapid self-healing capability, the hydrogel supports the growth, proliferation, and differentiation of hADSCs. Notably, encapsulated hADSCs form 3D spheroids during proliferation, with their sizes increasing over time alongside hydrogel degradation while maintaining high viability for at least 10 days. Additionally, hADSCs encapsulated in this hydrogel exhibit upregulated expression of chondrogenic differentiation genes and proteins compared to those cultured on 2D surfaces. These characteristics make the chitosan–PEG/PEG–dialdehyde hydrogel–stem cell construct suitable for direct implantation through minimally invasive injection, enhancing stem cell-based therapy for KOA and other cell-based treatments. [ABSTRACT FROM AUTHOR]

In this research, it was attempted to describe in vitro the efficiency of a natural polymer synthesized from sugarcane waste by bacteria for application in enhanced crude oil recovery. Necessary experiments were carried out with the main targets of extraction and description of the polymer and its effectiveness in enhanced oil recovery. It is shown that in the polymer concentrations of 1, 2, 5, and 8 wt%, the viscosity is equal to 26.08, 76.51, 100.94, and 168.36 mPa s. A shear‐thinning flow behavior is observed at initial shear rates. The sandstone wettability alteration is observed through the contact angles at concentrations of 1, 2, 5, and 8 wt% that are 85.93°, 72.19°, 76.51°, and 71.09°, respectively. Based on salinity compatibility, the polymer work up to a salinity of 90 000 ppm and based on viscosity tests, up to a salinity of 120 000 ppm. Regarding the performance of the polymer solution against temperature, it shows an acceptable performance in increasing the viscosity at the highest temperature of 75 °C. The water cut reaches its minimum of 8%, and then increases. By injecting 3.3 Pore volum (PV), the oil recovery reaches 81.4%. In a polymeric slug injection program, the oil recovery factor reaches 74.8%.Similarly, the water cut starts to decrease after the injection of polymer, and finally, after the injection of 0.9 PV including 0.5 PV of the polymer solution and 0.4 PV of water, reaches its minimum during the experiment, i.e., 22%. [ABSTRACT FROM AUTHOR]