Physicochemical Interactions Research Articles

Selezen А.О., Piskach L.V. INTERACTION IN THE QUASI-TERNARY Tl2Se–CdSe–SnSe2 SYSTEM

Selezen А.О., Piskach L.V. INTERACTION IN THE QUASI-TERNARY Tl2Se–CdSe–SnSe2 SYSTEM

Thymoquinone-Micellar Interactions: A physico-chemical investigation at molecular level

Thymoquinone (TQ) is considered the most-active component of the well-known essential oil of the black cumin/seeds (Nigella sativa L.), also known for its wide-spectrum anticancer and other pharmacological potentials since ancient times. Apart from its thermo- and photo-sensitive nature, TQ has also been reported to demonstrate strong hydrophobicity and low bioavailability. These physico-chemicals, properties hinder the development of a successful oral dosage formulation. Interaction of the pharmacologically active molecule with biological membranes is crucial step to manifest health-related effects. However, further insight into the biophysical interactions of “active” natural chemotherapeutics with cellular membranes can play a vital role in designing and developing new anti-cancer regimens. In this context pseudo-membrane models comprising ionic and non-ionic micelles offer a useful way to explore in vitro drug-membrane interactions at the molecular level. The present study focuses on the physicochemical interactions of a thymoquinone (TQ) with micelles of ionic (dodecyl trimethylammonium bromide, DTAB; and sodium dodecyl sulfate, SDS) and non-ionic (tween-80 and TX-100) surfactants at the molecular level in aqueous medium. Volumetric and acoustic parameters (apparent molar volume (ɸV), isentropic compressibility (Ks), apparent molar isentropic compressibility (ɸk), specific acoustic impedance (Z), relative association (RA), intermolecular free length (Lf)) are calculated from experimental data of density and sound velocity and interpreted in terms of solute/solvent–solute/solvent interactions using the co-sphere overlap model and the electrostriction effect. Further, UV spectroscopy and conductivity studies are used to predict the locus of TQ in the micelles, binding constant (Kb), partition coefficient (Kc), and free energy changes of TQ-micelle systems in the presence of surfactants. The results show that the binding and partitioning of TQ is more significant with TX-100 as compared with other ionic and non-ionic surfactants used.

A novel thermoplastic water-soluble sizing agent for the interfacial enhancement of carbon fiber/polyether ether ketone composites

Recently reported novel water-soluble polyether ether ketone (PEEK) derivative sizing agents have garnered considerable attention for improving interfacial bonding of carbon fiber-reinforced PEEK (CF/PEEK) composites. However, their extensive application is somewhat limited due to two drawbacks: the use of hazardous organic solvents in production and the retention of emulsifiers in sizing dispersion systems. Herein, an extremely hydrophilic sulfonated PEEK with a cardo group (S-PEEK-WC) was synthesized and used to prepare a water-soluble sizing agent. The S-PEEK-WC exhibits excellent thermal stability, with a 5 % decomposition temperature of 446.5 °C, and its aqueous solution remains stable for over six months. A robust interphase was also constructed in the CF/PEEK composites through multiple physicochemical interactions. Compared with the de-sized CF/PEEK composites, the interlaminar shear strength, flexural strength and interfacial shear strength of the CF2/PEEK composites improved by 57.9 %, 56.3 % and 44.8 %, respectively. This approach may shed some light on the development of a valid and environmentally friendly method for preparing water-soluble sizing agents of polyaryletherketone.

Different physicochemical interactions between varietal wines and human saliva: Correspondence with astringency

Astringency corresponds to the sensation of dryness and roughness that is experienced in the oral cavity in association with the interaction between salivary proteins and food polyphenols. In this study, the phenolic composition of seven varietal wines, the intensity of astringency they evoke and the physicochemical reactivity of these wines with whole human saliva were evaluated.Phenolic composition of wines was characterized by spectrophotometry and HPLC chromatography. Intensity of astringency was evaluated by trained sensory panels. Saliva from a single volunteer subject was used to assess wine-saliva interactions. To this end, binary mixtures were produced at different v/v wine/saliva ratios and each of them assayed for the ability of the salivary protein to diffuse on a cellulose membrane (diffusion test) and to remain in solution (precipitation test). Physicochemical reactivities between wine components and the protein fraction of saliva were contrasted against the astringency and the phenolic profile of each varietal wine. The study supports the view that astringency depends on physicochemical interactions between two complex matrices -wine and saliva- and not between some of their particular components.

Investigating corrosion failure in N80 carbon Steel: Experimental and theoretical insights into isonicotinohydrazide derivatives as inhibitors in acidic conditions

This research work is a detailed analysis of the failure mechanisms related to the corrosion of N80 carbon steel (N80-CS) in an acidic environment (15 wt% HCl), commonly encountered in oil and gas industry pipelines. The study investigates the corrosion failure, focusing on the interactions with two isonicotinohydrazide derivatives, namely N'-[(Z)-furan-2-ylmethylidene]pyridine-4-carbohydrazide (FMI) and N'-[(Z)-phenylmethylidene]pyridine-4-carbohydrazide (BIH). A combination of experimental and theoretical methods, including weight loss (WL), electrochemical analysis, Field Emission Scanning Electron Microscopy (FE-SEM), Atomic Force Microscopy (AFM), Density Functional Tight Binding (DFTB) semi-empirical calculations, frontier molecular orbital analyses, Fukui function studies, and molecular dynamics simulations, was utilized to identify the corrosion and corrosion inhibition behavior of N80-CS. Experimental findings demonstrated that the inhibition performance of FMI and BIH increased proportionally with the concentration of these inhibitors, demonstrating inhibition efficiencies of 95 %, and 98 %, respectively. This performance was reflected by the enhancement of polarization resistance and a significant reduction in corrosion current density at optimum concentrations. Additionally, they demonstrated exceptional corrosion protection capabilities over prolonged immersion times (up to 5 days) and only a moderate decrease in efficiency with increasing temperature, highlighting their robustness under varying operating conditions. The adsorption behavior of these inhibitors was observed to be in agreement with the Langmuir adsorption model, suggesting physicochemical interactions occurring at the N80-CS surface, specifically covalent bonding. Theoretical studies from DFT, molecular dynamics, and DFTB strengthened experimental results, confirming strong interactions between the inhibitors’ atoms and the surface. Through the integrative experimental and theoretical approach of this study, a comprehensive understanding of the mechanisms and inhibition performance of these studied compounds was achieved. The findings can serve as an invaluable resource towards the development of more efficient corrosion inhibitors, further contributing to the broader field of corrosion and prevention strategies.

Protein-protein and protein-nucleic acid binding site prediction via interpretable hierarchical geometric deep learning.

Identification of protein-protein and protein-nucleic acid binding sites provides insights into biological processes related to protein functions and technical guidance for disease diagnosis and drug design. However, accurate predictions by computational approaches remain highly challenging due to the limited knowledge of residue binding patterns. The binding pattern of a residue should be characterized by the spatial distribution of its neighboring residues combined with their physicochemical information interaction, which yet cannot be achieved by previous methods. Here, we design GraphRBF, a hierarchical geometric deep learning model to learn residue binding patterns from big data. To achieve it, GraphRBF describes physicochemical information interactions by designing an enhanced graph neural network and characterizes residue spatial distributions by introducing a prioritized radial basis function neural network. After training and testing, GraphRBF shows great improvements over existing state-of-the-art methods and strong interpretability of its learned representations. Applying GraphRBF to the SARS-CoV-2 omicron spike protein, it successfully identifies known epitopes of the protein. Moreover, it predicts multiple potential binding regions for new nanobodies or even new drugs with strong evidence. A user-friendly online server for GraphRBF is freely available at http://liulab.top/GraphRBF/server.

Methods for the Characterization of the Colloidal Properties of Bacterial Membrane Vesicles.

Bacterial membrane vesicles (BMVs) are extracellular vesicles secreted by either Gram-positive or Gram-negative bacteria. These BMVs typically possess a diameter between 20 and 250nm. Due to their size, when these BMVs are suspended in another medium, they could be constituents of a colloidal system. It has been hypothesized that investigating BMVs as colloidal particles could help characterize BMV interactions with other environmentally relevant surfaces. Developing a more thorough understanding of BMV interactions with other surfaces would be critical for developing predictive models of their environmental fate. However, this bio-colloidal perspective has been largely overlooked for BMVs, despite the wealth of methods and expertise available to characterize colloidal particles. A particular strength of taking a more colloid-centric approach to BMV characterization is the potential to quantify a particle's attachment efficiency (α). These values describe the likelihood of attachment during particle-particle or particle-surface interactions, especially those interactions which are governed by physicochemical interactions (such as those described by DLVO and xDLVO theory). Elucidating the influence of physical and electrochemical properties on these attachment efficiency values could give insights into the primary factors driving interactions between BMVs and other surfaces. This chapter details methods for the characterization of BMVs as colloids, beginning with size and surface charge (i.e., electrophoretic mobility/zeta potential) measurements. Afterward, this chapter will address experimental design, especially column experiments, targeted for BMV investigation and the determination of α values.

Performance and mechanism of sulfonamide-antibiotic adsorption by Ti3C2 MXene

Sulfachloropyridazine (SCP) antibiotics can be effectively adsorbed by Ti3C2 MXene with a qm of 22.62 mg g−1via physicochemical interaction.

Elucidating the role of physicochemical interactions on gel rheology.

Soft materials are characterized by their intricate interplay of structure, dynamics, and rheological properties. This complexity makes it challenging to accurately predict their response to shear stress. Here, we investigate how the nature of bonds - electrostatic attractions, physical entanglements, physical repulsion, and covalent bonds - affects the linear and nonlinear rheology of gels. Specifically, we determine the critical roles these bonds play in the yield transition and thixotropic recovery of gel properties through a combination of linear oscillatory deformations, serial creep divergence measurements, and time-resolved flow sweeps. Different classes of gels are prepared with nearly identical linear rheology but significantly different yield transitions and nonlinear properties post-yielding. These differences are directly related to the kinetics by which the underlying elastic networks rebuild after flow. Gels which exhibit thixotropic hysteresis are able to fully recover their yield stress over time while non-thixotropic gels possess time-independent yielding metrics. This direct comparison between thixotropy and yielding reveals the intimate relationship between these phenomena and their controlling physical mechanisms within soft, amorphous materials.

Research on the effect of microelement salt with fertilizer

The visual-polythermal method was used to study the solubility of components in the ZnSO4 – (NH4)2SO4 – H2O system over the temperature interval of -22.0°С to +36.1°С. Solubility and characteristics of the constituents of the system at different temperatures and concentrations were studied to show the physicochemical interactions between zinc sulfate and ammonium sulfate. The phase description delineates the areas of ice crystallization, (NH4)2SO4, ZnSO4ꞏ(NH4)2SO4ꞏ6H2O, and ZnSO4. A solubility diagram was drawn and a new compound, ZnSO4ꞏ(NH4)2SO4ꞏ6H2O, was isolated. The system ZnSO4 – (NH4)2SO4 – H2O was investigated using thirteen inner sections. At the double and triple points of the system, the equipoise composition of solutions and crystallization temperatures were clarified. The analysis was carried out using contemporary physicochemical analysis methods to confirm the identity of the obtained compound. Analytical data on physicochemical changes, thermal stability and chemical decomposition of the ZnSO4ꞏ(NH4)2SO4ꞏ6H2O sample with temperature change were presented. All the diffractographic changes in the X-ray pattern of a new compound, in particular, the set of distances between the planes, the activation of their reflection angles, and the diffraction lines confirm the individuality of the new compound.

Role of Graphene-related 2D Nanomaterials in Antimicrobial Potentials: An Overview

Microbial infections profoundly impact various facets of everyday life, imposing significant economic strains on healthcare systems worldwide and resulting in death. Researchers have made considerable attempts to restrict microbial proliferation, but effective antimicrobial agents still need to be improved. A highly effective strategy for mitigating this challenge involves utilizing antimicrobial materials with chemically embedded or inherent antimicrobial properties. Recently, carbon-based nanomaterials have shown promising antibacterial results. In particular, graphene- and graphene-derived nanomaterials (GMs) demonstrate a broad range of antimicrobial activity against bacteria, fungi, and viruses. These antibacterial activities are attributed mainly to the direct physicochemical interaction between GMs and bacteria that cause deadly cellular component degradation. GMs hold a high affinity for accumulating, leading to membrane damage; similarly, after internalization, they can interact with the bacterial genome, disrupting the replicative stage. Additionally, GMs can indirectly determine bacterial death by activating the inflammatory cascade after entering the physiological environment. This mini-review delves into the potential parameters influencing antimicrobial efficacy, encompassing the number of graphene layers, concentration, size, and structural characteristics. Additionally, it explores the antimicrobial mechanisms exhibited by the graphene family against a spectrum of pathogens. Finally, it presents various antimicrobial applications underlying GMs as promising materials applicable in different fields.

Detection of Secondary Metabolites in Cucumber (Cucumis sativus) Leaves and Its Potential as Candidates for Acne Drug Using Histochemical Analysis and In Silico Study

<p>Acne is a facial skin problem that is generally experienced by 75-80% of adolescents as a result of excessive production of oil glands and sweat, inflammatory mediators. The acnecausing bacteria, Propionibacterium acnes, involves KAS III and JNK 1 proteins, so it is expected to be an effective anti-inflammatory and antibacterial strategy. Cucumber leaves are known to have biological activity as a candidate for acne medication. This study aims to detect secondary metabolites in cucumber leaves through histochemical and in silico analysis. Histochemical analysis was carried out by preparing fresh leaves through lower leaf incisions by dropping secondary metabolite detection reagents and then observing the color changes microscopically. The in silico test aims to determine the physicochemical properties, pharmacokinetic properties and interactions of the active compounds with KAS III and JNK1 as acne drug targets through molecular docking. Histochemical analysis showed that cucumber leaves positively contained secondary metabolites, namely terpenoids, flavonoids, alkaloids, tannins, and phenols. Meanwhile, it was known that isovitexin, cucurbitacin B & C had fairly good physicochemical properties, but only isovitexin and cucurbitacin C had the best pharmacokinetic properties. Based on the results of molecular docking, there are the same amino acid bonds between isovitexin and the control at the JNK1 receptor, namely the amino acids Ile:32, Val:40 and Leu:168 and the binding affinity value is low so it is predicted to be the most effective in inhibiting JNK1. Therefore, cucumber leaves open up a new potential as a candidate for natural acne preparations.</p><p class="Abstract"><em>Keywords: acne</em><em>, cucumber</em><em>,</em><em> </em>secondary metabolites,<em> histochemical, in silico</em></p>

The relative contribution of mantle and continental crustal sources to primitive arc magmas: Insights from the early Palaeozoic Famatinian - Puna arc

Subduction zone magmatism plays a crucial role in driving the exchange of chemical elements between Earth's interior and surface. This survey focuses on the compositional analysis of primitive mafic rocks within an ancient Early Palaeozoic subduction-related magmatic belt. The primary objective is to assess the petrological processes involved in the cycling of chemical elements from the Earth's surface, through the slab and mantle reservoirs, to the crustal arc magmatic systems. By examining the composition of primitive mafic rocks and utilizing inverse modelling techniques, we estimate the composition of the ambient mantle source, which appears to have undergone depletion due to melt extraction before being metasomatized by slab agents. The inverse approach reveals that fluid-mobile elements (Th, U, La, Ce, and Sr) were primarily derived from the slab contribution and suggests that subduction had influenced the abundances of Nb and Ta in the modified mantle source. Conversely, Zr, Hf, and Ti were sourced from the ambient mantle. However, the available mineral/melt partition coefficients used in inverse modelling may overestimate the contribution of Sr and Nb from the slab. Instead, forward modelling is limited by the incomplete preservation of ancient volcanic arc geology. The forward mixing models that consider the interaction between slab-released sedimentary-derived melts and the ambient depleted mantle can explain the observed variations in Nd and Sr isotopic ratios in primitive mafic rocks. Two-component mixing shows that a small mass fraction (≤1.5 wt%) of average Cambrian continental sediments subducted beneath the Early Ordovician arc into a MORB-depleted mantle source account for the abundance of sedimentary-supplied elements such as Th, La, and Ba, as well as radiogenic isotope ratios of 143Nd/144N and 87Sr/86Sr in the primitive mafic magmas. The chemical and isotopic composition of deep-seated primitive mafic rocks reveals a decoupling between incompatible trace elements, which display minimal variation, and radiogenic isotopic ratios, which exhibit a wide range and reflect contributions from continental crustal reservoirs. To explain the observed variations in trace elements and isotopes, we propose a simple model involving simultaneous bulk assimilation (A) and imperfect fractional crystallization (IFC) in an open igneous system, where crystal accumulation and assimilation occur concurrently. Especially, deep crustal physicochemical interaction of primitive arc magmas with supracrustal host rocks may mask the expected clear signature of subarc mantle petrological processes. Our assessment of the Famatinian-Puna arc, an ancient subduction zone, concurs with estimates from active volcanic arcs, underscoring the general applicability of this study case to subduction zone magmatism.

Microplastics enhance the adsorption capacity of zinc oxide nanoparticles: Interactive mechanisms and influence factors

Microplastics (MPs) are of particular concern due to their ubiquitous occurrence and propensity to interact and concentrate various waterborne contaminants from aqueous surroundings. Studies on the interaction and joint toxicity of MPs on engineered nanoparticles (ENPs) are exhaustive, but limited research on the effect of MPs on the properties of ENPs in multi-solute systems. Here, the effect of MPs on adsorption ability of ENPs to antibiotics was investigated for the first time. The results demonstrated that MPs enhanced the adsorption affinity of ENPs to antibiotics and MPs before and after aging showed different effects on ENPs. Aged polyamide prevented aggregation of ZnONPs by introducing negative charges, whereas virgin polyamide affected ZnONPs with the help of electrostatic attraction. FT-IR and XPS analyses were used to probe the physicochemical interactions between ENPs and MPs. The results showed no chemical interaction and electrostatic interaction was the dominant force between them. Furthermore, the adsorption rate of antibiotics positively correlated with pH and humic acid but exhibited a negative correlation with ionic strength. Our study highlights that ENPs are highly capable of accumulating and transporting antibiotics in the presence of MPs, which could result in a widespread distribution of antibiotics and an expansion of their environmental risks and toxic effects on biota. It also improves our understanding of the mutual interaction of various co-existing contaminants in aqueous environments.

Novel protocol for fouling detection of reverse osmosis membrane based on methylene blue colorimetric method by image processing technique.

In the current study, a novel methylene blue (MB)-based colorimetric method for a quick, inexpensive, and facile approach for the determination of fouling intensity of reverse osmosis (RO) membrane has been reported. This technique is based on the interaction of MB with the organic foulants and shows the corresponding change in the colour intensity depending on the severity of fouling. The organic foulants, such as albumin, sodium alginate, and carboxymethyl cellulose (CMC), were chosen as model foulants, and the membranes were subjected to foul under extreme fouling conditions. The fouled membranes underwent an MB treatment followed by image-processing analyses. The severity of surface fouling of membranes was evaluated in terms of fouling intensity and correlated with the corresponding decline of permeate flux. The maximum fouling intensity of the albumin, sodium alginate, and CMC sodium were found to be 8.83, 23.38, and 9.19%, respectively, for the definite concentration of foulants. The physico-chemical interactions of the given foulants and MB were confirmed by changes in zeta potentials and increased sizes of the foulant by the dynamic light scattering technique. The surface fouling over the membrane surface was confirmed by the characterization of membranes.

Measurement of Acefylline Piperazine Interaction and Dissociation Constants in Polymer Solvent Systems

In this study the physicochemical interactions of acefylline piperazine drug (APD) were examined in aqueous and aqueous polymer systems viz., aqueous polyethylene glycol (1.0 %w/v) and aqueous polyvinyl pyrrolidone (1.0% w/v). The study was carried within the concentration ranges from 2.0×10-2 to 10.0 ×10-2 mol/dm3 at different temperatures (293.15 to 318.15 K with the difference of 5 K). Various analytical methods such as conductometric, refractometry, and liquid chromatographic (RP-HPLC) were applied. In order to observe the interaction of APD, o m was calculated to evaluate the structural influence of polymers on the mobility of solute (APD) at different temperatures. α, Kd and Walden product of APD were also assessed in aqueous polyethylene glycol and aqueous polyvinyl pyrrolidone. Solvation was observed by Walden's product showing strong solvation of APD in water-soluble polymer systems. Thermodynamic parameters for APD such as * E , ΔG*, ΔH*and ΔS* have also been evaluated as a function of temperature to determine the exo/endothermic nature of the drug dissociation process. Specific refraction, molar refraction and polarizability of APD in aqueous and aqueous polymer systems were calculated using the Lorentz-Lorentz equation and various interactions were interpreted. Drug's compatibility studies were also performed by HPLC in aqueous and aqueous polymer systems.

Molecular interactions of cationic/anionic surfactants in presence of anionic antibiotic drug cloxacillin sodium at different temperatures: Micellization and thermodynamic studies

The physicochemical properties and interactions of surfactant–drug aggregates are regarded as essential features to achieve optimum therapeutic action of the drug. In this article, the effect of various concentrations of anionic antibiotic drug cloxacillin sodium (ClxNa) on the micellization of cationic surfactants such as cetyltrimethylammonium bromide (CTAB), tetradecyltrimethylammonium bromide (TTAB) and anionic surfactant sodium dodecyl sulphate (SDS) have been investigated using electrical conductance measurement at different temperatures (288.15 K, 293.15 K, 298.15 K, 303.15 K, 308.15 K, and 313.15 K). The results suggest an increase in critical micelles concentration (CMC) values for cationic surfactants (CTAB/TTAB) with a rise in drug concentration (0 mM up to 10 mM) whereas anionic surfactant SDS shows a decrease in CMC at higher drug concentrations (from 2.5 mM up to 10 mM) at all the studied temperatures. The degree of counterion dissociation (α) values for TTAB aggregates show a slight increase with [ClxNa], except at a few lower temperature ranges whereas such a regular trend was not obtained for CTAB and SDS aggregates. Temperature-dependent CMC values show a nonlinear nature with a rise in temperatures and follow a U-shaped curve for all studied pure surfactant and surfactant–ClxNa systems. Micellization for all surfactant-drug systems is found to be spontaneous. Investigation of other temperature-dependent thermodynamic parameters such as change in standard enthalpy (ΔHm0), and entropy (ΔSm0) of micellization suggest that surfactant–drug interactions are both endothermic (ΔHm0 < 0, particularly at lower temperatures) and exothermic (ΔHm0 < 0, at higher temperatures), whereas micellization is largely entropically driven (ΔSm0 > ΔHm0).

Structural Heredity in Catalysis: CO2 Self-Selective CeO2 Nanocrystals for Efficient Photothermal CO2 Hydrogenation to Methane.

The chemical inertness of CO2 molecules makes their adsorption and activation on a catalyst surface one of the key challenges in recycling CO2 into chemical fuels. However, the traditional template synthesis and chemical modification strategies used to tackle this problem face severe structural collapse and modifier deactivation issues during the often-needed post-processing procedure. Herein, a CO2 self-selective hydrothermal growth strategy is proposed for the synthesis of CeO2 octahedral nanocrystals that participate in strong physicochemical interactions with CO2 molecules. The intense affinity for CO2 molecules persists during successive high-temperature treatments required for Ni deposition. This demonstrates the excellent structural heredity of the CO2 self-selective CeO2 nanocrystals, which leads to an outstanding photothermal CH4 productivity exceeding 9mmol h-1 mcat -2 and an impressive selectivity of >99%. The excellent performance is correlated with the abundant oxygen vacancies and hydroxyl species on the CeO2 surface, which create many frustrated Lewis-pair active sites, and the strong interaction between Ni and CeO2 that promotes the dissociation of H2 molecules and the spillover of H atoms, thereby greatly benefitting the photothermal CO2 methanation reaction. This self-selective hydrothermal growth strategy represents a new pathway for the development of effective catalysts for targeted chemical reactions.

Physicochemical investigations of interaction of antitumor etoposide with ionic and nonionic micelles: a spectroscopic, conductivity and voltammetric study

This work aims to comprehend the physicochemical interaction of etoposide (trade name “VP-16”) with biological membranes using biomembrane models. Surfactants, owing to their remarkable chemical similarity with biomembranes, can be used to simulate the interactions and behavior of VP-16 in biological systems. The present study explores the physicochemical interactions of chemopreventive VP-16 with ionic dodecyltrimethylammonium bromide (DTAB), sodium dodecyl sulfate (SDS), and nonionic TX-100 & Tween-80 surfactants at the molecular level using different techniques. UV-visible spectroscopy results at 298.15 K indicate that both hydrophilic and hydrophobic interactions significantly influence the solubility of the drug in micellar systems. According to the estimated partition coefficient (Kx ) and binding constant (Kb ) obtained from the differential mode of the UV-Vis, VP-16 exhibits better binding and partitioning with nonionic surfactants compared to ionic surfactants. Thermodynamic parameters ( Δ H m o , Δ S m o , & Δ G m o ) are computed from 298.15 K to 318.15 K with a temperature interval of 5 K using conductivity data. The positive values of Δ H m o and Δ S m o and the negative values of Δ G m o indicate the disruption of water structure during the micellization process in the presence of VP-16 and the spontaneous transport of drug molecules into micelles, respectively. Voltammetric data at 298.15 K show that DTAB and TX-100 favor the oxidation of VP-16. This kind of study may be used to modify currently available drugs, design new chemotherapeutics, and formulate effective drug delivery systems to boost the drugs bioavailability.

Development of 1-phenyl-3-(4-(pyridin-4-ylmethyl)phenyl)urea derivatives as robust corrosion inhibitors for mild steel in 1 M HCl environment: Insight from ,molecular, experimental, and microscopic-scale modelling approaches

Cost-effective, novel urea derivatives, 1-phenyl-3-(4-(pyridin-4-ylmethyl)phenyl)urea (U-1), 1‐(4‐fluorophenyl)‐3‐(4‐(pyridin‐4‐ylmethyl)phenyl)urea (U-2), and 1‐(4‐methylphenyl)‐3‐(4‐(pyridin‐4‐ylmethyl)phenyl)urea (U-3) were synthesized to investigate as the corrosion inhibitors for mild steel/1 M HCl interface. Inhibition efficiency increases with the increasing inhibitor’s concentration but decreases with increasing temperature. Thermodynamic adsorption and activation parameters demonstrate that the adsorption of inhibitors follows Langmuir isotherm via physicochemical interactions. Potentiodynamic polarization measurements reveal that the inhibitors are mixed-type, impeding the charge-transfer process. Surface analysis supports a thin inhibitor film formation on the mild steel. The maximum inhibition efficiency of U-1, U-2 and U-3 are 94.97 ± 0.38%, 93.60 ± 0.62% and 97.42 ± 0.48% respectively. The calculated electrochemical impedance spectra (EIS) parameters such as ohmic resistance, double layer capacitance, relaxation time, effective thickness, and conductivity of grain and grain boundary are in-line with the efficiencies of NHUs. The performance of corrosion inhibitors follows a sequence U-3 > U-1 > U-2, emphasizing the influence of the substituent’s inductive effect (-CH3 > -H > -F) in inhibitors. Density functional theory (DFT) was performed to understand the correlation between molecular structure and inhibition efficiency. The Fukui indices confirm the presence of local attacking sites on the metal surface where inhibitors attack. A molecular dynamic (MD) simulation is used to determine the interaction energies between the inhibitors and mild steel. Radial Distribution Function (RDF) measurements confirm the existence of the chemical nature of the interaction. Furthermore, the diffusion coefficient of corrosive particles, self-diffusion coefficient of inhibitors, fractional free volume (FFV), and interaction between inhibitor’s film and corrosive particles are examined. Theoretical studies support experimental results.