Search Results (178)

Soil moisture regulation is critical for vegetation restoration in arid ecosystems. Polymeric hydrogels, notably polyacrylic acid (PAA) and polyacrylamide (PAM), are widely employed as water-retaining agents to enhance soil water availability. However, the coupling between their distinct chemical structures and key performance metrics, particularly cycling stability and water retention kinetics in desert substrates, remains unclear. In this work, we present an integrated experimental–computational study to establish a “molecular structure–interfacial behavior–macroscopic property” framework for PAA and PAM. The results show that PAA exhibits a higher equilibrium water absorption (WAC ~242 g/g) and more stable water uptake capacity under cycling, whereas PAM displays much higher zero-shear viscosity and pronounced shear thinning with a yield plateau (~30 Pa). DFT and MD simulations trace these macroscopic disparities to their distinct electronic structures and hydration dynamics. Specifically, PAA’s strong electrostatic interactions and extended chain conformations promote a more rigid and ordered hydration shell, whereas PAM adopts a compact structure with greater chain mobility, resulting in a less ordered hydration layer. Collectively, these findings provide a structure-property framework for the scientifically grounded selection of water-retaining agents. The integrated experimental–computational methodology presented herein establishes a predictive framework for the rational design of functional materials in arid land restoration. Full article

The interface between synthetic materials and biological systems is a critical determinant of performance in medical devices and biosensors. This review examines the evolution of biointerface science through the lens of self-assembled monolayers (SAMs) of thiols on gold, a model system that offers atomic-level control over surface chemistry. We trace the field from the foundational structural characterization to the establishment of empirical design rules for bio-inertness. While early theoretical models attributed protein resistance to steric repulsion forces in polymer brushes, contemporary understanding has shifted toward the “water barrier” hypothesis, which posits that tightly bound interfacial water prevents direct biomolecular contact. We highlight recent studies that extend these concepts into “realistic” crowded biological environments. Their work reveals that fouling surfaces in crowded media generate a “viscous interphase layer” (VIL) that extends tens of nanometers into solution, whereas zwitterionic surfaces maintain a robust hydration shell that prevents this accumulation. Furthermore, this hydration barrier is shown to fundamentally alter bacterial mechanics, forcing microorganisms into a reversible, tethered “hovering” state at a significant biological interaction distance (>100 nm) from the surface, effectively precluding biofilm nucleation. These insights underscore that the future of antifouling material design lies in the precise engineering of interfacial hydration structures. Full article

Wellbore instability in shale formations represents a worldwide challenge in drilling engineering. The development of high-performance shale stabilizers is crucial for enhancing wellbore stability. A core–shell structured shale stabilizer, designated AAD-CaCO₃, was synthesized via inverse emulsion polymerization using acrylamide (AM), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), and dimethyl diallyl ammonium chloride (DMDAAC) as monomers. Nano-CaCO₃ was generated in situ by reacting calcium chloride and sodium carbonate. Sodium bisulfite and ammonium persulfate were used as initiators. The product was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). Its effects on the rheological properties and filtration performance of a bentonite-based mud were evaluated. The stabilizer’s efficacy in inhibiting shale hydration swelling and dispersion was evaluated through linear swelling tests and shale rolling dispersion experiments, while its plugging performance was examined via a filtration loss test with a nanoporous membrane and spontaneous imbibition tests. The results indicated that AAD-CaCO₃ possesses a core–shell structure with the nano-CaCO₃ encapsulated by the polymer. It moderately improved the rheology of the bentonite-based mud and significantly reduced both the low-temperature and low-pressure (LTLP) filtration loss and the high-temperature and high-pressure (HTHP) filtration loss. AAD-CaCO₃ could be adsorbed onto shale surfaces through electrostatic attraction, resulting in substantially reduced clay hydration swelling and an increased shale cutting recovery rate. Effective plugging of micro-nanopores in shale was achieved, demonstrating a dual mechanism of chemical inhibition and physical plugging. Full article

During the transportation of oil and gas pipelines, the adhesion and aggregation of hydrate particles on the pipe wall are prone to cause pipeline blockage, which seriously impairs the safe and efficient transportation of energy. Taking cyclopentane hydrates as the research object, this study investigated the effects of contact time, wall wettability, and the concentration of kinetic hydrate inhibitor poly(N-vinylcaprolactam) (PVCap) on the adhesion force between hydrates and the wall of X80 pipeline steel by combining a high-precision micromechanical force measurement system with microscopic morphology observation and analysis. The results show that the adhesion force increases with prolonged contact time: it is dominated by capillary liquid bridge force in the initial contact stage with slow growth, and after exceeding the critical time, the sintering effect becomes the dominant factor, leading to a rapid rise in adhesion force that eventually tends to stabilize. Wall wettability significantly influences the adhesion force, and enhanced wettability improves the adhesion force by increasing the liquid bridge volume and the hydrate–wall contact area. PVCap concentration exerts a non-monotonic effect on adhesion force—first decreasing and then increasing. At low concentrations (0.25–1 wt%), PVCap molecules adsorb on the hydrate surface to form a physical barrier, reducing adhesion force. At high concentrations (1.5–2 wt%), excessive PVCap damages hydrate shell integrity, releasing free water to expand the liquid bridge volume and increase adhesion force. This study provides a theoretical basis for eliminating or reducing hydrate blockage in deep-sea oil and gas pipelines. Full article

Background: Lewisite, a potent chemical warfare agent, induces rapid and progressive cutaneous damage, necessitating treatment strategies that offer both immediate decontamination and prolonged therapeutic action. This study aimed to develop and evaluate a composite topical formulation comprising 4-phenylbutyric acid (4-PBA)-loaded emulsomes embedded within a foam vehicle to address both aspects of vesicant-induced skin injury intervention. Methods: Emulsomes composed of a stearic acid–cholesterol solid lipid core stabilized by a lecithin shell were prepared via thin film hydration and optimized by varying lipid ratios and drug loading parameters. Formulations were characterized for drug loading, particle size, and zeta potential. Physicochemical compatibility was assessed using Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) analyses. Stability was evaluated under accelerated refrigerated (25 °C/60% RH) and room temperature (40 °C/75% RH) conditions. The optimized formulation was incorporated into a foam base and evaluated for decontamination efficiency, drug release kinetics, in vitro permeation, and in vivo efficacy. Results: The selected formulation (E2) exhibited high drug loading (17.01 ± 0.00%), monodisperse particle size (PDI = 0.3 ± 0.07), and stable zeta potential (−40 ± 1.24 mV). FTIR and DSC confirmed successful encapsulation with amorphous drug dispersion. The emulsome-foam demonstrated dual functionality: enhanced decontamination (66.84 ± 1.27%) and sustained release (~30% over 24 h), fitting a Korsmeyer–Peppas model. In vitro permeation showed significantly lower 4-PBA delivery from E2 versus free drug, confirming sustained release, while in vivo studies demonstrated therapeutic efficacy. Conclusions: This emulsome-foam system offers a promising platform for topical treatment of vesicant-induced skin injury by enabling both immediate detoxification and prolonged anti-inflammatory drug delivery. Full article

This study presents a modification strategy to fabricate core–shell composite aggregates from reclaimed asphalt pavement (RAP), aligning with green chemistry principles for waste valorization. The method involves creating a porous cementitious shell on the surface of RAP particles through a controlled hydration process. This surface modification simultaneously addresses the inherent structural weaknesses and irregular morphology of raw RAP, enabling the design of materials with desired properties. A face-centered central composite design (FCCD) was employed to optimize the synthesis process, elucidating the nonlinear relationships between key synthesis parameters and the final material characteristics. The optimized synthesis yielded porous aggregates with significantly enhanced structural integrity, evidenced by a 43.9% reduction in crushing value. Furthermore, the surface modification effectively regulated the material’s morphology and particle size distribution, leading to a 3.6 mm increase in median particle size (D₅₀) and a 27.69% decrease in the content of fines (<4.75 mm). Microstructural characterization confirmed the formation of a rough, porous cementitious shell composed of hydration products, which provides the structural basis for the material’s enhanced performance. This work establishes a clear structure–property relationship, demonstrating a new pathway for the rational design and synthesis of functional porous materials from solid waste for application in high-grade pavements. Full article

Latent heat thermal energy storage (LHTES) using inorganic salt hydrates is a promising technology for buffering renewable energy fluctuations; however, phase-dependent heat transfer remains insufficiently understood for design optimization. In this study, a shell-and-tube storage module with a circular-finned tube was constructed and filled with 13.17 kg of barium hydroxide octahydrate (BHO). Discharge tests were conducted with heat transfer fluid (HTF) inlet temperatures ranging from 20 °C to 50 °C and flow rates of 10–25 L/min, while charging was performed at 90 °C. The overall heat transfer coefficient (${\mathrm{U}}_{\mathrm{o}}$) was derived using the logarithmic mean temperature difference method, the inside coefficient (h_i) was calculated by the Petukhov correlation, and the outside coefficient (h_o) was obtained via thermal-resistance network. Results show that the average discharge energy was approximately 1.027 kWh (except 0.859 kWh at 50 °C inlet), with a mean utilization efficiency of 79.25%. The ${\mathrm{U}}_{\mathrm{o}}$ was consistently highest in the liquid phase, followed by the latent and solid phases, with ranges of 0.257–0.863, 0.025–0.072, and 0.015–0.044 kW/m²·°C, respectively. Sensitivity analysis revealed that the HTF flow rate strongly influenced U_o across all phases, whereas inlet temperature played only a minor role. The outside coefficient ${\mathrm{h}}_{\mathrm{o}}$ was 0.033–0.162 kW/m²·°C in the latent regime and 0.018–0.064 kW/m²·°C in the solid regime, with a notable peak around Reynolds number 1.3 × 10⁴ in the latent phase. These findings provide detailed phase-resolved ${\mathrm{U}}_{\mathrm{o}}$ and ${\mathrm{h}}_{\mathrm{o}}$ data for inorganic salt hydrate storage and highlight design insights such as the diminishing returns of flow rate increase beyond a threshold, offering valuable guidelines for sizing and operation of LHTES in Power-to-Heat applications. Full article

Cowhide collagen (CC) is a valuable by-product of the meat industry with promising applications in food systems; however, its poor viscosity and limited stability restrict its practical use. This study systematically investigated the interactions between CC and three representative polysaccharides—xanthan gum (XG), gellan gum (GG), and chitosan (CS)—under varying concentrations, pH, and ionic strengths. The physicochemical behaviors of the composite systems were evaluated through turbidity, fluorescence spectroscopy, Fourier transform infrared (FTIR) analysis, and rheological measurements. The experimental results revealed a pronounced increase in the turbidity of the GG–CC system, rising from approximately 0.18 ± 0.01 to 2.14 ± 0.01 as the polysaccharide concentration increased, with maximum values exceeding 2.0 under several conditions. Similarly, both the apparent viscosity and turbidity of the other two PS–CC composite systems exhibited a marked and progressive enhancement with increasing polysaccharide content. FTIR spectra confirmed strengthened O–H stretching and amide I shifts, indicating intensified hydrogen bonding and electrostatic interactions. High NaCl levels disrupted the protein hydration shell, modifying fluorescence intensity and peak sharpness. XG–CC and GG–CC composites exhibited similar behaviors, while CS–CC systems showed opposite pH-dependent trends due to cationic–cationic repulsion. Overall, polysaccharide type and concentration exerted stronger effects on CC structure and rheology than environmental factors. These results clarify how polysaccharide type and environmental factors modulate collagen–polysaccharide interactions and provide practical guidance for selecting polysaccharides and processing conditions to tailor the rheological and stability properties of collagen-based food ingredients. Full article

Increasing evidence suggests that, under physiological conditions, the carbonate anion radical CO₃^•− could be the major source of oxidative stress, instead of the commonly accepted hydroxyl radical HO^•. In aqueous solutions, CO₃^•− exists as a hydrated species, which may influence its properties and activities. CO₃^•− acts as a one-electron oxidant via a single electron transfer (SET) mechanism. Impact of the number of explicit water molecules (0, 4, 6, and 9) on inactivation of CO₃^•− by Trolox, a water-soluble analog of α-tocopherol, was theoretically investigated using the DFT approach. Also, the role of Trolox solvation by H-bonded water molecules was examined. The obtained results indicate that an increased number of explicit water molecules in CO₃^•− hydration shell increases exergonicity and decreases the reaction barrier of the SET pathway, causing minor alterations of intrinsic reactivity, i.e., apparent rate constant. Amongst Trolox species, explicit hydration of the dianion has a notable impact on the reaction rate. Trolox belongs to phenolic antioxidants, but electron transfer to CO₃^•− proceeds from the aromatic part of the chroman moiety rather than from the phenoxide or carboxylate group of ionic species. The presented microhydration approach may serve as a way for estimating the potency of natural and synthetic compounds to suppress oxidative damage caused by CO₃^•−, a topic scarcely computationally considered so far. Full article

As a result of global urbanization, the construction industry has mainly emitted CO₂ from ordinary Portland cement (OPC). Partially replacing cement with supplementary cementitious materials is a widely studied approach for reducing emissions. While previous studies have explored binary systems such as fly ash (FA)–cement and oyster shell powder (OSP)–cement, limited research has been conducted on ternary systems that combine FA, OSP, and cement. The differences in macro- and microsustainability performance between binary and ternary mixes remain unclear and require further exploration. To address this gap, this study verified the feasibility of using FA and OSP for partially replacing OPC in concrete. The environmental and mechanical performances of these materials were evaluated through macro- and microlevel experiments, as well as through life cycle assessments (LCAs). The results show that there is a synergistic effect in the FA-OSP-OPC ternary mixed cement (28-day strength: 40.44 MPa), which promotes the hydration of the three-component cement. Compared with the FA-OPC (28-day strength: 39.38 MPa) and OSP-OPC (28-day strength: 26.85 MPa) two-component cements, the strength is increased by 2.7% and 50.61%, respectively. At the same time, the resistivity of the three-component cement is also increased. The resistivity is increased by 19.27% ((50.69 − 42.5)/42.5) compared with the pure cement group. On this basis, the three-component cement also reduces carbon emissions by about 15% ((13.09 − 11.19)/13.09). FA-OSP-OPC ternary mixed cement improves strength and durability, reduces carbon emissions, and is an excellent new ternary mixed gel material that can be sustainably utilized. Full article

The durability of cement-based materials can be reduced by the invasion of water and ions from external environments. This can be alleviated by reducing the surface wettability. To evaluate the anti-wetting performances of different graphene-based materials, a molecular dynamics simulation was performed to investigate the wetting behaviors of water and NaCl droplets on a tobermorite surface coated with graphene and functionalized graphene (G-NH₂ and G-CH₃). The results demonstrate that functionalized graphene displays weak surface binding with water and ions, significantly weakening droplet wettability. Moreover, functionalized graphene surfaces exhibit reduced ion immobilization capacity compared with a pristine tobermorite surface. It obviously increases the number of free ionic hydration shells, thus amplifying the influence of ionic cage restriction. Specifically for the G-CH₃ surface, the contact angle of the NaCl droplet reaches 94.8°, indicating significant hydrophobicity. Furthermore, the adhesion between functionalized graphene and tobermorite is attributed to the interlocking characteristics of these materials. Hopefully, this study can provide nanoscale insights for the design of functionalized graphene coatings to improve the durability of cement-based materials under harsh environments. Full article

Herein, a brief overview of the cyclodextrin structure is provided, along with its most important derivatives. The difference between the water molecules in the outer hydration shell of cyclodextrin and those in its hydrophobic cavities is discussed. The structural characteristics of surfactants, along with their structural differences, are presented. An insight into the formation of surfactant micelles was given in aqueous solution. A thermodynamic model for the formation of the inclusion complex between surfactants and cyclodextrin in a solution is presented, explaining the hydrophobic effect, which drives the formation of the inclusion complex at lower and room temperatures. The influence of the size of the cyclodextrin cavity and the structure of surfactants on the stoichiometry of the inclusion complex, as well as on the affinity of the surfactant to the hydrophobic cavity of cyclodextrin, is discussed. The most important experimental methods used to study the cyclodextrin-surfactant inclusion complex are listed. Full article

Poly(carboxybetaine methacrylate)s (PCBMA) belongs to a class of zwitterionic polymers that offer promising alternatives to polyethylene glycol (PEG) in biomedical applications. This review highlights how the unique zwitterionic structure of PCBMA dictates its strong antifouling behavior, low immunogenicity, and sensitivity to environmental stimuli such as pH and ionic strength. These features make PCBMA promising for designing advanced systems suited for complex biological environments. This review describes PCBMA-based materials—ranging from hydrogels, nanogels, and surface coatings to drug carriers and protein conjugates—and critically evaluates their performance in drug delivery, tissue engineering, diagnostics, and implantable devices. Comparative studies demonstrated that PCBMA consistently outperformed other zwitterionic polymers and PEG in resisting protein adsorption, maintaining bioactivity of conjugated molecules, and ensuring long circulation times in vivo. Molecular dynamics simulations provide additional information into the hydration shells and conformational behaviors of PCBMA in aqueous dispersions. These insights underscore PCBMA’s broad potential as a promising high-performance material for next generation healthcare technologies. Full article

Electrons localized by water molecules are known as hydrated electrons. The composition of the aqueous environment determines their state and behavior. In this experimental and theoretical work, hydrated electrons were formed in aqueous solutions upon high-energy electron impact, and the dependence of their characteristics on the presence of nanobubbles generated during vibrational treatment was investigated. To explain the results, quantum chemical simulations were carried out, and diverse possible kinetic schemes were considered. Absorbance of deionized water and NaCl aqueous solution was measured at a wavelength of 600 nm, which falls in the range typical of hydrated electrons. The principal differences in the spectral responses of the samples were discovered depending on whether they were preliminarily subjected to repeated vigorous shaking or not. Vigorous shaking caused a noticeable increase in both the integral and maximum absorbance, and the absorbance decay was significantly slower. The effects observed in the vibrationally treated aqueous samples were found to be explained only in the framework of a kinetic scheme that assumes the repeated solvation of electrons, which are transferred from a localized to a delocalized (free) state upon the energy absorption. This repeated solvation is possible only when the secondary electrons are localized on the inner surfaces of the boundary hydration shells of nanobubbles, which are formed in the process of shaking. Thus, nanobubbles substantially change the apparent gross lifetime and properties of hydrated electrons, and these changes, in turn, can indicate the presence of nanobubbles in water and aqueous solutions. Full article

This study aims to clarify the temperature-dependent degradation mechanisms of the steel–concrete interface in NaCl solution environments at the nanoscale, focusing on the key components of calcium silicate hydrate (C-S-H, the primary hydration product of cement) and iron oxyhydroxide (γ-FeOOH, a critical component of steel passive films in highly alkaline environments). Using Materials Studio software (2023) and molecular dynamics simulations, the evolution of the interface’s performance under temperatures ranging from 300 K to 390 K (corresponding to 27 °C to 117 °C) is systematically investigated. The results reveal that elevated temperatures degrade the performance of C-S-H/γ-FeOOH interfaces through three main mechanisms: (1) The stability of the hydration shell around aggressive ions is weakened, enabling these ions to occupy the coordination positions of calcium ions on the interface and form stable ion pairs with surface calcium ions, thereby weakening interfacial bonding. (2) The mobility of surface calcium ions is enhanced, reducing the strength of the interaction of ion pairs and diminishing the mediating role of calcium ions in connecting the C-S-H and γ-FeOOH phases. (3) Hydrogen bond stability at the interface decreases, as indicated by reduced hydrogen bond angles and numbers, coupled with increased hydrogen bond lengths. The above three reasons lead to a decrease in adsorption energy in the C-S-H/γ-FeOOH interface, which degrades the interface bond’s performance. Full article