Salt Concentration Research Articles

In situ formation of ultrahigh molecular weight polymers in highly concentrated electrolytes and their physicochemical properties.

We developed a facile one-pot method for fabricating physical gels consisting of ultrahigh molecular weight (UHMW) polymers and highly concentrated lithium salt electrolytes. We previously reported physical gels formed from the entanglement of UHMW polymers by radical polymerisation in aprotic ionic liquids. In this study, we found that the molecular weight of methacrylate polymers formed by radical polymerisation increased with the concentration of lithium salts in the organic solvents. Consequently, the synthesis of UHMW polymers with a high monomer conversion was achieved at very low initiator concentrations, leading to the formation of physical gels in highly concentrated electrolytes by the chain entanglement of UHMW polymers. The viscoelastic and mechanical properties of the UHMW gel electrolytes and their self-healing properties were investigated in detail.

FRET analysis of the unwrapping of nucleosomal DNA containing a sequence characteristic of the + 1 nucleosome

Sequence-dependent mechanical properties of DNA could play essential roles in nuclear processes by affecting histone-DNA interactions. Previously, we found that the DNA entry site of the first nucleosomes from the transcription start site (+ 1 nucleosome) in budding yeast enriches AA/TT steps, but not the exit site, and the biased presence of AA/TT in the entry site was associated with the transcription levels of yeast genes. Because AA/TT is a rigid dinucleotide step, we considered that AA/TT causes DNA unwrapping. However, our previous MNase-seq experiments with reconstituted nucleosomes left some doubt regarding this interpretation, owing to its high exonuclease activity. Furthermore, MNase cleavage did not provide direct evidence of its structural state. In this study, Förster resonance energy transfer (FRET) measurements were used to investigate salt-induced conformational changes in nucleosomal DNA containing AA/TT repeats at the entry site. We observed that the AA/TT region wrapped around the histone core was as likely as other DNA sequences at physiological salt concentrations. However, it unwrapped at a lower salt concentration, indicating weaker electrostatic interactions with the histone core. Ethidium-induced nucleosome disruption assay showed that the intercalator had greater access to DNA with AA/TT at the entry site. Taken together, these results suggest that AA/TT at the entry sites induces DNA unwrapping from the histone core on the promoter side, which may promote transcriptional activation in response to the approach of transcription-related proteins.

Creating a Halotolerant Degrader for Efficient Mineralization of p-Nitrophenol-Substituted Organophosphorus Pesticides in High-Saline Wastewater.

The bioaugmentation performance is severely reduced in the treatment of high-saline pesticide wastewater because the growth and degradation activity of pesticide degraders are significantly inhibited by high salt concentrations. In this study, a heterologous biodegradation pathway comprising the seven genes mpd/pnpABCDEF responsible for the bioconversion of p-nitrophenol (PNP)-substituted organophosphorus pesticides (OPs) into β-oxoadipate and the genes encoding Vitreoscilla hemoglobin (VHb) and green fluorescent protein (GFP) were integrated into the genome of a salt-tolerant chassis Halomonas cupida J9, to generate a genetically engineered halotolerant degrader J9U-MP. RT-PCR assays demonstrated that the nine exogenous genes are successfully transcribed to mRNA in J9U-MP. Gas chromatography analysis of methyl parathion (MP) and its intermediates demonstrated that the expressed MP hydrolase and PNP-degrading enzymes PnpABCD show obvious degradation activity toward the specific substrates in J9U-MP. Stable isotope analysis showed that J9U-MP is able to efficiently convert 13C6-PNP into 13CO2, demonstrating the complete mineralization of MP in high-salt media. J9U-MP is genetically stable during passage culture, and genomic integration of exogenous genes does not negatively influence the growth of J9U-MP. Under oxygen-limited conditions, VHb-expressing J9U-MP does not show obvious growth inhibition and a significant reduction in the MP degradation rate. A real-time monitoring system with enhanced GFP is used to track the motion and activity of J9U-MP during bioremediation. Moreover, 50 mg/L MP and its intermediates (i.e., PNP and HQ) were completely degraded by J9U-MP within 12 h in wastewater supplemented with 60 g/L NaCl. After 3 days of incubation, 25 mg/L 13C6-PNP was converted into 13CO2 by J9U-MP in wastewater supplemented with 60 g/L NaCl. Our results highlight the power of synthetic biology for creating new halotolerant pollutant-mineralizing strains. The strong competitive advantages of J9U-MP in high-salinity and low-oxygen environments make this degrader suitable for in situ bioaugmentation of OP wastewater.

Molecular foundations for shear-induced dynamics of natural organic matter.

The overall objective of the present work was to quantify how shear, coupled with varying salt concentration, affected the particle size distribution and relaxation/aggregation behavior for various organic sources of nonliving natural organic matter (NNOM) in surface water. NNOM has been implicated as a conditioning agent leading to the formation of biofilms such as algae. NNOM is also a responsible in surface waters for facilitated transport of a variety of anthropogenic pollutants. These are NNOM surface-related phenomena, yet the variable surface area and surface composition of NNOM, which can change dependent on shear rate, is not discussed in the literature. NNOM polymer-like dynamics can interact with stream water velocity differences to determine the process and result of aggregation. The fundamental role of post-shear NNOM molecular structure and dynamic aggregation (self-assembly) is examined here alongside fresh (hydrological) versus mined (terrestrial) NNOM. Shear rate can be seen as a change in the velocities of streamlines in hydrology. In this early work, the response to shear rate for three types of NNOM was measured using a stress-controlled rheometer under varying conditions of ionic strength. Samples were studied for rheological response after a variety of pre-shear conditions, and data then coupled with surface composition data from previously reported fluorescence studies. Interestingly, a size class of 5μm aggregates disappeared when Aldrich humic acid samples were treated with 0.3M Ca2+. Evidence is also presented that the environmental samples flocculated at shear rates up to 400s-1, rather than exhibiting particle breakup, with implications for reducing NNOM surface area. Dynamic response of different NNOM sources was not the same, some sources showing evidence of self-assembly. The molecular response to shear may play an important role in understanding the surface area and composition of NNOM responsible for facilitated transport of pollutants and initiation of biofilms.

Experimental Investigation on Thermo-Economic Analysis of Direct Contact Membrane Distillation for Sustainable Freshwater Production

Treatment of extremely saline water such as the brine rejected from reverse osmosis water desalination plants, and produced water from shale oil and non-conventional gas extraction, is considered a global problem. Consequently, in this work, hollow fiber membrane distillation (HFMD) is experimentally evaluated for desalinating extremely saline water of a salinity ranging from 40,000 to 130,000 ppm. For the purpose of comparison, the HFMD is also tested for desalinating brackish (3000–12,000 ppm) and sea (25,000–40,000 ppm) water. Firstly, the HFMD is tested at two values of feed water temperature (65 and 76 °C) and flow rate (600 and 850 L/h). The experimental results showed that the HFMD productivity significantly increases when the temperature of feed water increases. Increasing the feed water flow rate also has a positive effect on the productivity of HFMD. It is also concluded that the productivity of the HFMD is not significantly affected by increasing the salt concentration when brackish and sea water are used. The productivity also slightly decreases with increasing the salt concentration when extremely saline water is used. The decrement in the productivity reaches 27%, when the salt concentration increases from 40,000 to 130,000 ppm. Based on the conducted economic analysis, the HFMD shows a good potential for desalinating extremely saline water especially when the solar collector is used as a heat source. In this case, the cost per liter of freshwater is reduced by 21.7–23.1% when the evacuated tube solar collectors are used compared to the system using electrical heaters. More reduction in the cost per liter of freshwater is expected when a high capacity solar-powered HFMD plant is installed.

Ionic Strength-Induced Compartmentalization for Nanogel-in-Microgel Colloids.

Compartmentalization is crucial for control over complex biological cascade reactions. In microgels, the formation of discrete compartments allows for simultaneous uptake and orthogonal release of physicochemically distinct drugs, among others. However, many state-of-the-art approaches yielding compartmentalized microgels require the use of specific, though not always biocompatible, components and temperatures well above the physiological range, which may damage possible biological cargo. Therefore, a novel technique to fabricate compartmentalized microgels by exploiting ionic strength-induced precipitation as a mechanism for compartmentalization is developed. For this, a droplet-based microfluidic approach in which preformed nanogels are incorporated into poly(N-isopropylacrylamide)- or poly(acrylamide)-based microgels is employed. Allowing contact between the nanogel-monomer mixture and a salt solution only at the cross junction inhibits premature precipitation of the nanogels and aggregates form on the chip. It is demonstrated that this method is applicable to a variety of nanogel species in both stimuli-responsive and non-stimuli-responsive microgel networks. For temperature-responsive nanogel compartments in non-responsive microgels, anisotropic shape change is investigated by adjusting temperature or salt concentration or changing the solvent. Lastly, an exemplary uptake and release experiment demonstrates highly selective drug absorption, paving the way for more advanced biomimetic polymer structures.

Solid-State Nanopore Real-Time Assay for Monitoring Cas9 Endonuclease Reactivity.

The field of nanopore sensing is now moving beyond nucleic acid sequencing. An exciting avenue is the use of nanopore platforms for the monitoring of biochemical reactions. Biological nanopores have been used for this application, but solid-state nanopore approaches have lagged. This is due to the necessity of using higher salt conditions (e.g., 4 M LiCl) to improve the signal-to-noise ratio which completely abolish the activities of many biochemical reactions. We pioneered a polymer electrolyte solid-state nanopore approach that maintains a high signal-to-noise ratio even at a physiologically relevant salt concentration. Here, we report the monitoring of the restriction enzyme SwaI and CRISPR-Cas9 endonuclease activities under physiological salt conditions and in real time. We investigated the dsDNA cleavage activity of these enzymes in a range of digestion buffers and elucidated the off-target activity of CRISPR-Cas9 ribonucleoprotein endonuclease in the presence of single base pair mismatches. This approach enables the application of solid-state nanopores for the dynamic monitoring of biochemical reactions under physiological salt conditions.

Synthesis of Arsenocholine-Type Polycation Brush and Its Hydration Structure in Aqueous Solution.

Arsenocholine-containing methacrylate (MTAsB) inspired by marine organisms was synthesized by the reaction of 2-bromoethyl methacrylate and trimethylarsine to investigate its polymerization behavior and the fundamental properties of the resulting polymer. Controlled radical polymerization of MTAsB proceeded in the presence of a copper catalyst and imidazolium chloride at 60 °C for 8 h to give a water-soluble polycation with a 94% yield. The smaller amount of nonfreezing water and intermediate water of poly(MTAsB) was observed compared with that of the ammonium-containing polycations. A poly(MTAsB) brush was also prepared on a silicon substrate to investigate its swelling structure in aqueous salt solution by scanning probe microscopy and neutron reflectivity measurements. The brush chains adopted a relatively extended conformation in pure water because of the Coulombic repulsion among the arsenic cation groups of the polyelectrolyte, while the brush formed a collapsed structure in aqueous solutions of Hofmeister series anions as a result of the screening effect by salt ions. In particular, thiocyanate ions induced a significant reduction in the swollen thickness of the brush, probably caused by the attractive interaction between arsenic cations and chaotropic thiocyanate ions. The salt concentration dependency of the poly(MTAsB) brush was similar to that of the ammonium-cation-type polyelectrolyte brushes.

Sensory Analysis of a Greek Yoghurt Spread with Blends of Butter and Salt

Aims: To design and evaluate a nutritious Greek yoghurt spread, exploring optimal combinations of butter and salt to elevate sensory satisfaction Study Design: The study was experimental and laboratory-based, focusing on optimizing the base for low-fat functional Greek yoghurt spread production. Place and Duration of Study: The study was carried out at the Department of Dairy Technology, Dairy Science College, Hebbal, Bengaluru, Karnataka, India, during the period from January 2024 to October 2024. Methodology: The Greek yoghurt spread was prepared using standardized cow milk (4% fat), fermented with a mixed starter culture of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. Initially, the butter content was varied at levels of 30%, 40%, and 50%, followed by adjustments to salt concentrations at 0.5%, 1.0%, and 1.5%. Sensory evaluation of the prepared samples was conducted by a trained panel using a 9-point hedonic scale, assessing attributes such as flavour, colour and appearance, body and texture, spreadability, and overall acceptability. Data were statistically analyzed using ANOVA, and significant differences were identified with critical differences (CD) at a 5% significance level. Results: Increasing butter content significantly enhanced flavour, spreadability, and overall sensory acceptability, with the 40% butter sample achieving the highest scores for all attributes. Similarly, the inclusion of 1% salt improved flavour, texture, and overall acceptability compared to other concentrations. The optimized formulation with 40% butter and 1% salt received the highest sensory ratings, indicating a balance of creaminess, spreadability, and palatability. Conclusion: The study demonstrated that a butter concentration of 40% and a salt concentration of 1% are optimal for achieving superior sensory quality in low-fat functional Greek yogurt spreads. These optimized formulations provide a nutritious, protein-rich, and lower-fat alternative to traditional high-fat spreads, combining sensory appeal with health benefits. The findings offer valuable insights for developing innovative dairy spreads that cater to health-conscious consumers, delivering a wholesome, flavorful, and versatile product without compromising on taste or nutritional value.

Comparative Analysis of the Corrosion Behavior of Plain and Nanoporous Copper

This research investigates the corrosion behavior of copper (Cu) through a comprehensive analysis of both plain and nanoporous Cu thin films. A combination of weight-loss methods for quantitative analysis, along with polarization testing and scanning electron microscopy, is employed for both quantitative and qualitative assessments of Cu corrosion dynamics. The corrosion mechanisms in chloride and nitrate solutions are compared, with an additional discussion on the influence of atmospheric oxygen (O2). The results demonstrate that chloride ions and the presence of O2 create the most severe corrosion conditions, while the concentration of salts has a relatively minor effect on the corrosion behavior. Notably, the comparative study reveals that nanoporous Cu exhibits a greater corrosion tendency, as indicated by more negative corrosion potentials. However, its corrosion rates are lower than those of plain Cu, as determined by corrosion current density measurements.

Direct cytosol delivery of mRNA by micron-sized co-assembly with designer oligopeptides.

Inefficient endosomal escape has been regarded as the main bottleneck for intracellular nucleic acid delivery. While most research efforts have been spent on designing various nano-sized particles, we took a different path here, investigating micron-sized carriers for direct cytosol entry. Using the spontaneous co-assembly of mRNA and the designer 27 amino acid oligopeptide named pepMAX2, micron-sized co-assemblies were obtained with various sizes by altering the concentration of NaCl salt and time for pre-incubation. Surprisingly, transfection was much more effective using micron-sized than nano-sized co-assemblies, and the efficiency surpasses that of a widely used lipid-based commercial reagent. The study was complemented by computational simulations, inhibitor studies and live-cell confocal imaging to shed light on the role of electrostatic interaction on assembly and the mechanism of uptake and intracellular trafficking. These micron-sized co-assemblies directly enter the cytosol and then release mRNA, bypassing conventional pathways and thus avoiding the lysosomal degradation. This simple approach involving short oligopeptides and salt addition to create optimal micron-sized co-assembly with mRNA should open new avenues to overcome endosomal barriers for intracellular delivery of nucleic acid therapeutics.

Green Synthesis of Zinc Oxide Nanoparticles Including Rosehip (Rosa canina L.) Seed Extract: Evaluation of Its Characterization and Bioactivity Properties.

The use of bioactive compounds in plants as reducing, stabilizing, and capping agents in nanoparticle manufacturing is an exceptionally eco-friendly approach. This work used rosehip seed extract, acquired by automatic solvent extraction, in the microwave-assisted green production of zinc oxide nanoparticles (ZnO NPs). The total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity of the extracted materials and nanoparticles (NPs) were assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays. The ideal synthesis parameters were established as 25mL of extract, pH 12, 360W of microwave power, and a metal salt concentration of 0.05M for a duration of 7min. The characterization of the ZnO NPs synthesized under these conditions was performed using x-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy with energy-dispersive x-ray analysis (SEM-EDX), dynamic light scattering (DLS), zeta potential measurements, and UV-Vis spectrophotometry. High-purity, nano-sized, antioxidant ZnO NPs were manufactured using an ecologically friendly, sustainable, and ecological technique.

Ion Networks in Water-based Li-ion Battery Electrolytes.

ConspectusWater-in-salt electrolytes (WiSEs) are promising electrolytes for next-generation lithium-ion batteries (LIBs), offering critical advantages like nonflammability and improved safety. These electrolytes have extremely high salt concentrations and exhibit unique solvation structures and transport mechanisms dominated by the formation of ion networks and aggregates. These ion networks are central to the performance of WiSEs, govern the transport properties and stability of the electrolyte, deviating from conventional dilute aqueous or organic electrolytes.The availability of free water molecules is significantly reduced in WiSEs, leading to a shift in the solvation environment. Lithium ions (Li+) typically travel with their solvation shells in dilute solutions and form stronger interactions with anions, resulting in the formation of complex ion aggregates. Despite the high viscosity of WiSEs, they exhibit surprisingly high ionic conductivity attributed to the decoupling of viscosity and ionic mobility. Instead of moving through free water, Li+ ions are transported along the pathways formed by the ion networks, minimizing direct solvent interaction and enhancing mobility.Advanced spectroscopic techniques, such as infrared IR pump-probe (IR-PP) and two-dimensional IR (2D-IR) spectroscopy, and molecular dynamics (MD) simulations have illuminated the critical role of these ion networks in facilitating transport. These studies have shown that even at extreme salt concentrations, some water molecules retain properties similar to bulk water, essential for fast ion movement. In WiSEs, bulk-like water molecules form transient hydrogen-bond networks that serve as conduits for Li+ ions, while anion-bound water molecules play a less active role in transport due to their slower dynamics.As the salt concentration increases, the structure of WiSEs becomes more dominated by 3D ion networks. MD simulations reveal that these networks, stabilized by chaotropic anions such as bis(trifluoromethanesulfonyl)imide (TFSI-), disrupt the hydrogen-bonding network of water and provide a stable, interconnected structure that supports the movement of Li+ ions. The formation of these extensive ion networks is critical for maintaining ionic mobility and the electrochemical stability of the electrolyte.The shift from traditional vehicular transport mechanisms to structural diffusion is a hallmark of WiSEs. Li+ ions no longer move with their solvation shells but hop between coordination sites within the ion network. This structural diffusion mechanism enables high ionic mobility despite the reduced presence of water and the increased viscosity of the solution. In conclusion, the formation of ion networks and aggregates in WiSEs not only stabilizes the electrolyte but also drives an unconventional ion transport mechanism. By understanding and controlling these aggregates, WiSEs offer a pathway toward safer, high-performance electrolytes for LIBs and other aqueous energy storage technologies.

Asymmetric ion transport through heterogeneous bilayers of covalent organic frameworks

In recent years, with the development of interfacial polymerization methodologies, the successful preparation of covalent organic framework (COF) monolayers featuring ultrahigh pore density and molecule-scale thickness has become a reality. This advancement has enabled ion transport with ultrahigh flux across extremely short paths. Owing to these processes, the COF monolayers have shown wide potential applications ranging from energy conversion and artificial mechanosensing to ion sieving. To date, nanofluidic systems based on COF monolayers are homogeneous, leading to nearly symmetric ion transport properties. Studies on the ionic transport behavior within ultrathin COF heterojunctions are limited and remain challenging. Herein, using a two-step sequential self-assembly and subsequent interfacial polymerization strategy, bi-layered heterogeneous tetraphenylporphyrin-based COF membranes composed of negatively charged and positively charged monolayers were prepared. Using an electric field as a driving force, rectified ion transport was observed for the first time. Notably, this ionic current rectification property could be modulated by the salt concentration and the structural composition of the membrane, and it was universal for various COF heterojunctions with different chemical ingredients. These findings are beneficial for promoting the development of innovative nanofluidic materials and devices.

Biochar Amendment Alleviates the Risk of High-Salinity Saltwater Intrusion for the Growth and Yield of Rice (Oryza sativa L.).

Saltwater intrusion poses a serious risk to global food security. As a soil amendment, biochar mitigates the negative effects of saltwater intrusion in rice, yet the beneficial effects on agricultural productivity with different exposure times and salt concentrations have not been fully examined. A pot experiment was conducted to investigate the effects of 30% (w/w) rice husk biochar on the growth, ion accumulation, and yield of the Phitsanulok 2 rice cultivar under salt stress due to saltwater intrusion. Rice plants were grown in saline soil amended with biochar and were salinized with 6, 8, and 10 dS/m saltwater for 1, 2, and 3 months. A treatment without biochar was taken as the control. The results showed that biochar amendment significantly increased the survival, shoot height, and tiller numbers of rice treated with the 6-10 dS/m saltwater for 1 and 2 months, as well as the treatment with 6 dS/m salt water for 3 months, in comparison with the control. The grain yield was about 40 g/pot for rice with biochar treated for 1 month with 6-10 dS/m saltwater and for the rice treated for 2 months with 6 dS/m. The results indicated that biochar application could alleviate the intrusion of high-salinity water for 1 month of salt exposure, and it could alleviate the intrusion of medium-salinity water for 2 months. Therefore, a 30% (w/w) rice husk biochar amendment is a reliable strategy for mitigating the risks of saltwater intrusion for the growth and productivity of rice.

Molecular Dynamics Simulation Study on Heterogeneous Structure, Rheology, and Dynamic Correlation of Concentrated Aqueous Solutions of a Lithium Salt.

Molecular dynamics simulation of an aqueous solution of lithium bis(trifluoromethanesulfonyl)amide, LiTFSA, was performed at various concentrations to relate its liquid structure with frequency-dependent shear viscosity. The structure factor exhibited a low-q peak that represents a heterogeneous structure composed of water and anion domains, and the lithium ion existed in the water domain due to its strong hydration. The frequency-dependent shear viscosity showed bimodal relaxation, and the relative contribution of the slower mode increased with an increase in the salt concentration. The cross-correlation between the shear stress and the two-body density revealed that the slower viscoelastic mode is assigned to the dynamics of the heterogeneous structure, and the assignment was also confirmed by the comparison between the viscoelastic and structural relaxations. The collective translational motions of the cation and the anion showed a strong negative correlation in a concentrated solution, reflecting the heterogeneous domain structure.

AozC, a zn(II)2Cys6 transcription factor, negatively regulates salt tolerance in Aspergillus oryzae by controlling fatty acid biosynthesis

BackgroundIn the soy sauce fermentation industry, Aspergillus oryzae (A. oryzae) plays an essential role and is frequently subjected to high salinity levels, which pose a significant osmotic stress. This environmental challenge necessitates the activation of stress response mechanisms within the fungus. The Zn(II)2Cys6 family of transcription factors, known for their zinc binuclear cluster-containing proteins, are key regulators in fungi, modulating various cellular functions such as stress adaptation and metabolic pathways.ResultsOverexpression of AozC decreased growth rates in the presence of salt, while its knockdown enhanced growth, the number of spores, and biomass, particularly under conditions of 15% salt concentration, doubling these metrics compared to the wild type. Conversely, the knockdown of AozC via RNA interference significantly enhanced spore density and dry biomass, particularly under 15% salt stress, where these parameters were markedly improved over the wild type strain. Moreover, the overexpression of AozC led to a downregulation of the FAD2 gene, a pivotal enzyme in the biosynthesis of unsaturated fatty acids (UFAs), which are essential for preserving cell membrane fluidity and integrity under saline conditions. Transcriptome profiling further exposed the influence of AozC on the regulation of UFA biosynthesis and the modulation of critical stress response pathways. Notably, the regulatory role of AozC in the mitogen-activated protein kinase (MAPK) signaling and ABC transporters pathways was highlighted, underscoring its significance in cellular osmotic balance and endoplasmic reticulum homeostasis. These findings collectively indicate that AozC functions as a negative regulator of salt tolerance in A. oryzae.ConclusionThis research suggest that AozC acts as a negative regulator in salt tolerance and modulates fatty acid biosynthesis in response to osmotic stress. These results provide insights into the regulatory mechanisms of stress adaptation in A. oryzae.

On Diffusiophoresis of a Soft Particle with a Hydrophobic Inner Core: A Semianalytical Study.

The current study deals with a theoretical analysis of diffusiophoresis of a soft particle, consisting of a hydrophobic charged rigid core coated with an ion- and fluid-penetrable charged polymer layer suspending in an electrolyte medium in reaction to an applied concentration gradient. The inner core's hydrophobicity is assumed to be characterized by a surface-charge-dependent slip length parameter. Based on a weak particle charge consideration, the governing equations describing the flow phenomena are solved theoretically to deduce a semianalytic general diffusiophoretic mobility expression applied to an arbitrary Debye layer thickness. A closed-form analytic solution is also obtained, which applies to a thin Debye length and low permeable porous layer. The impact of the charge-dependent wettability of the rigid core on the particle's diffusiophoretic motion is analyzed. We found that the inner core's hydrophobicity profoundly influences the particle mobility at a thicker Debye layer with a constant surface charge density when the chemiphoresis and electrophoresis components assist each other. At a fixed ζ-potential, the effect of the hydrophobic core is substantial for a thinner Debye length. In addition, with a critical selection of core and polymer layer charges, mobility reversal is demonstrated by modulating the salt concentration and slip length parameters.

IDENTIFICATION OF COARSE AGGREGATES PRONE TO SURFACE DETERIORATION AND D-CRACKING IN CONCRETE PAVEMENTS

This study investigates the influence of coarse aggregates on the durability of concrete pavements exposed to freezing and thawing cycles, particularly focusing on the phenomena of surface deterioration and D-cracking. Argillaceous aggregates from Indiana pavements showed significant surface damage within one to two years of construction, despite being from approved sources and the concrete being air entrained for freeze-thaw protection. The deterioration was linked to the aggregates themselves, with no apparent damage to the surrounding cement paste. The research aimed to understand the role of osmotic effects in the aggregates' failure by conducting laboratory experiments to simulate the freezing conditions with and without salt solutions. The findings revealed that the argillaceous aggregates exhibited osmotic phenomena, leading to an additional detrimental mechanism during freezing and thawing when a salt concentration gradient exists. This study confirms the significant impact of osmotic pressure on aggregate failure and suggests a simple testing procedure to identify aggregates prone to such deterioration. The results have implications for the selection and testing of coarse aggregates used in concrete pavements, particularly in environments where deicing agents are applied. (Abstract generated by AI tool ChatGPT 4)

Block Copolymer Electrolytes with Double Primitive Cubic Structures: Enhancing Solid-State Lithium Conduction via Lithium Salt Localization.

We present a strategy for enhancing Li+ conduction in block copolymer electrolytes by introducing trace amounts of Li salts into polystyrene-b-poly(ethylene oxide) (PS-b-PEO), wherein Li+ ions preferentially coordinate with the -OH end groups of the PEO chains, resulting in the formation of double primitive cubic (Im3̅m) structures. Compared with TFSI- anions in Li salts, smaller anions (PF6- and BF4-) could facilitate ion localization more effectively, expanding the salt concentration range for developing stable Im3̅m structures. The Im3̅m structures formed in PS-b-PEOs doped with LiBF4 at r = 0.013-0.02 (r ≡ [Li+]/[EO]) exhibited ionic conductivities several times higher than those doped at the conventional level (e.g., r = 0.06). The corresponding morphology factors were more than eight times higher than those of the lamellar-forming electrolytes. Notably, the activation energy value for Li+ conduction in PS-b-PEO with one Li+ ion per entire PEO chain was only 0.012 eV (by Vogel-Fulcher-Tammann), indicating that Li+ transport was less dependent on polymer relaxation. Furthermore, modifying the PEO chain ends with three -PO3H2 groups further strengthened the Li+-mediated end-end interactions and significantly extended the salt concentration range to form Im3̅m structures. In contrast, increasing the number of -OH end groups (such as diols and triols) had minimal effect on stabilizing the network morphologies.