Search Results (36)

Wax deposition, driven by the crystallization of long-chain n-alkanes, poses severe challenges across industries such as petroleum, oil and natural gas, food processing, and chemical manufacturing. This phenomenon compromises flow efficiency, increases energy demands, and necessitates costly maintenance interventions. Wax inhibitors, designed to mitigate these issues, operate by altering wax crystallization, aggregation, and adhesion over the pipelines. Classic wax inhibitors, comprising synthetic polymers and natural compounds, have been widely utilized due to their established efficiency and scalability. However, synthetic inhibitors face environmental concerns, while natural inhibitors exhibit reduced performance under extreme conditions. The advent of nano-based wax inhibitors has revolutionized wax management strategies. These advanced materials, including nanoparticles, nanoemulsions, and nanocomposites, leverage their high surface area and tunable interfacial properties to enhance efficiency, particularly in harsh environments. While offering superior performance, nano-based inhibitors are constrained by high production costs, scalability challenges, and potential environmental risks. In parallel, the development of “green” wax inhibitors derived from renewable resources such as vegetable oils addresses sustainability demands. These eco-friendly formulations introduce functionalities that reinforce inhibitory interactions with wax crystals, enabling effective deposition control while reducing reliance on synthetic components. This review provides a comprehensive analysis of the mechanisms, applications, and comparative performance of classic and nano-based wax inhibitors. It highlights the growing integration of sustainable and hybrid approaches that combine the reliability of classic inhibitors with the advanced capabilities of nano-based systems. Future directions emphasize the need for cost-effective, eco-friendly solutions through innovations in material science, computational modeling, and biotechnology. Full article

The insufficient corrosion resistance and high interfacial contact resistance (ICR) of 316L stainless steel (316L SS) severely limit its application as bipolar plates (BPs) in proton exchange membrane fuel cells (PEMFCs). In this study, a graphite/carbon black/PVDF composite coating was first developed by hot rolling on the surface of 316L SS to enhance both corrosion resistance and conductivity. By incorporating 5 wt% polyaniline (PANI) as a corrosion inhibitor, the optimized RP5 coating exhibited further improvements in corrosion resistance. The potentiodynamic polarization tests revealed that the RP5 coating achieved a corrosion current density of 0.977 μA·cm⁻², representing a two-orders of magnitude reduction compared to bare 316L SS (34.1 μA·cm⁻²). The coating also exhibits a satisfactory interfacial contact resistance (ICR) of 8.20 mΩ·cm² at 1.5 MPa, meeting the U.S. Department of Energy (DOE) 2025 targets (<10 mΩ·cm²). Additionally, the RP5 coating exhibited superior hydrophobicity with a water contact angle of 96.5°, which is advantageous for water management within PEMFCs. The results confirm that the RP5 coating achieves an optimal balance between high conductivity, excellent corrosion resistance, and improved hydrophobicity, making it a promising solution for advancing PEMFC bipolar plates’ performance. Full article

Area-selective atomic layer deposition (AS-ALD) is a technique utilized for the fabrication of patterned thin films in the semiconductor industry due to its capability to produce uniform and conformal structures with control over thickness at the atomic scale level. In AS-ALD, surfaces are functionalized such that only specific locations exhibit ALD growth, thus leading to spatial selectivity. Self-assembled monolayers (SAMs) are commonly used as ALD inhibiting agents for AS-ALD. However, the choice of organic molecules as viable options for AS-ALD remains limited and the precise effects of ALD nucleation and exposure to ALD conditions on the structure of SAMs is yet to be fully understood. In this work, we investigate the potential of small molecule carboxylates as ALD inhibitors, namely benzoic acid and two of its derivatives, 4-trifluoromethyl benzoic acid (TBA), and 3,5-Bis (trifluoromethyl)benzoic acid (BTBA) and demonstrate that monolayers of all three molecules are viable options for applications in ALD blocking. We find that the fluorinated SAMs are better ALD inhibitors; however, this property arises not from the hydrophobicity but the coordination chemistry of the SAM. Using nanoscale infrared spectroscopy, we probe the buried monolayer interface to demonstrate that the distribution of carboxylate coordination states and their evolution is correlated with ALD growth, highlighting the importance of the interfacial chemistry in optimizing and assessing ALD inhibitors. Full article

Phospholipase A2 (PLA2) is a superfamily of phospholipase enzymes that dock at the water/oil interface of phospholipid assemblies, hydrolyzing the ester bond at the sn-2 position. The enzymatic activity of these enzymes differs based on the nature of the substrate, its supramolecular assemblies (micelle, liposomes), and their composition, reflecting the interfacial nature of the PLA2s and requiring assays able to directly quantify this interaction of the enzyme(s) with these supramolecular assemblies. We developed and optimized a simple, universal assay method employing the pH-sensitive indicator dye bromothymol blue (BTB), in which different POPC (3-palmitoyl-2-oleoyl-sn-glycero-1-phosphocholine) self-assemblies (liposomes or mixed micelles with Triton X-100 at different molar ratios) were used to assess the enzymatic activity. We used this assay to perform a comparative analysis of PLA2 kinetics on these supramolecular assemblies and to determine the kinetic parameters of PLA2 isozymes IB and IIA for each supramolecular POPC assembly. This assay is suitable for assessing the inhibition of PLA2s with great accuracy using UV-VIS spectrophotometry, being thus amenable for screening of PLA2 enzymes and their substrates and inhibitors in conditions very similar to physiologic ones. Full article

Attalea phalerata Martius ex Spreng is a palm tree that is widely distributed in the Central-West region of Brazil. In this study, we investigated whether the oil-loaded nanocapsules of A. phalerata (APON) have acute and long-lasting antihypertensive effects in male spontaneously hypertensive rats (SHR), as well as explored the underlying molecular mechanisms. APON was prepared using the interfacial polymer deposition method. The particle size, polydispersity index, and zeta potential were investigated using dynamic and electrophoretic light scattering. The antihypertensive effects of APON (administered at doses of 1, 3, and 10 mg/kg) were evaluated after acute intraduodenal administration and after 7 days of oral treatment. To investigate the molecular pathways involved, we used pharmacological antagonists and inhibitors that target prostaglandin/cyclic adenosine monophosphate, nitric oxide/cyclic guanosine monophosphate, and potassium channels. Both acute and prolonged administration of APON (at doses of 3 and 10 mg/kg) resulted in a significant reduction in systolic, diastolic, and mean arterial pressure. Prior treatment with a non-selective nitric oxide synthase inhibitor (Nω-nitro-L-arginine methyl ester), guanylyl cyclase inhibitor (methylene blue), or non-selective calcium-sensitive K⁺ channel blocker (tetraethylammonium) abolished the antihypertensive effects of APON. Our study showed that A. phalerata oil-loaded nanocapsules have a significant antihypertensive effect in SHR after both short-term and long-term (7-day) use. This effect seems to rely on the vascular endothelium function and involves the NO-cGMP-K⁺ channel pathway. This research suggests a new direction for future studies to definitively prove the therapeutic benefits of APON in treating cardiovascular disease. Full article

Three-dimensional (3D) integration has become a leading approach in chip packaging. The interconnection density and reliability of micro-bumps in chip stacking are often threatened by high bonding temperatures. The method of building chip-to-chip interconnections by electroless deposition of metal has its distinct merit, while the interfacial defect issue, especially that related to voiding during the merging of opposite sides, remains largely unsolved. In this study, to trace the influencing factors in the voiding, the growth characteristics of the electroless all-copper interconnections were examined by carrying out deposition experiments in a microfluidic channel device. The results show that when the gap between the opposite copper bumps to be electrolessly merged is as low as 10 μm, significant voids appear at the inflow side and the top of the copper bumps because the hydrogen cannot be expelled in time. A finite-element flow model of the plating solution between the chips was established, which showed that the flow rate of the plating solution around the copper bumps was much higher than in the merging gap, causing an uneven supply of reactants. Based on these findings, we proposed two potential solutions, one is to improve the flow mode of the plating solution, and the other is to add the reaction inhibitor, 2,2′-bipyridine. Finally, the combination of these two approaches successfully achieved an improved merging quality of the copper joints. Full article

To investigate structural changes, the Cu95Fe5 alloy system was subjected to cooling rates of 1 × 10¹³ K/s, 2 × 10¹² K/s, 2 × 10¹¹ K/s, and 2 × 10¹⁰ K/s using the molecular dynamics simulation method. The results revealed that decreasing the cooling rate caused an increase in the phase transition temperature. Further, the structure of the alloy system exhibited a tendency towards increased stability following cooling at lower cooling rates. The Fe precipitation behavior of the Cu95Fe5 alloys during cooling at the rate of 2 × 10¹⁰ K/s was further explored, with the results suggesting that the formation and growth of the Fe cluster is a continuous process governed by the nucleation and growth mechanism. The size and number of Fe clusters formed at different stages were found to be affected by three factors, namely, the interaction force between the Fe atoms, the diffusion ability of the Fe atoms, and the interfacial energy between the Fe cluster and Cu matrix. When the alloy temperature exceeded 1400 K, the accumulation of the Fe atoms was facilitated by their strong interaction. However, the high temperatures and the large diffusion coefficient of the Fe atoms acted as inhibitors to the growth of Fe clusters, despite the intense thermal activities. As the temperature was reduced from 1400 K to 1050 K, the Fe atoms moved with a reduced intensity in a narrower area, and both the number of Fe atoms in the largest cluster and the number of clusters increased due to the action of the interaction force between the Fe atoms. Upon lowering the temperature from 1050 K to 887 K, the size of the largest Fe cluster increased rapidly, while the number of clusters decreased gradually. The growth of the largest Fe cluster could be partly attributed to the diffusion of single Fe atoms into the cluster under the action of the interaction force between the Fe atoms, in addition to the gathering and combination of multiple clusters. When the temperature was lowered from 967 K to 887 K, the diffusion coefficient of the Fe atoms approached 0, indicating that the non-diffusive local structure rearrangements of atoms dominated in the system structure change process. The interface energy governed the combination of the Fe clusters in this stage. At a temperature below 887 K, the alloy crystallized, the activities of the Fe atoms were reduced due to a low temperature, and the movement range of the Fe atoms was small at a fast cooling rate. As such, both the size and number of Fe clusters showed no obvious changes. Full article

Green corrosion inhibitors are gaining recognition for their sustainable, cost-effective, and environmentally friendly nature, along with their impressive water solubility and high corrosion inhibition efficiency. They offer a promising solution to combat corrosion issues that plague various industries. However, to harness the full potential of these eco-friendly corrosion inhibitors, a profound understanding of their development and underlying mechanisms is essential. This knowledge is the key to paving the way for the next generation of corrosion protection materials. Herein, a comprehensive study was conducted to understand the adsorption, corrosion inhibition efficiency, and stability of 3-benzoyl-4-hydroxy-2,6-bis(4-methoxyphenyl)-4-phenylcyclohexane-1,1-dicarbonitrile (BMPD). This study investigated the performance of BMPD applied to carbon steel (CS) in 1 M hydrochloric acid (HCl) solution. The corrosion inhibition effect was examined using weight loss, potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and theoretical studies. The surface morphology was also characterized and Tafel polarization analysis shows that BMPD is a mixed inhibitor. The results obtained by electrochemical impedance spectroscopy indicate that the inhibitory effect increases with increasing inhibitor concentration. The adsorption of BMPD on a CS surface obeyed the Langmuir adsorption isotherm. Thermodynamic parameters were calculated and discussed. Furthermore, this study involved a comprehensive computational analysis of the BMPD compound. Using quantum chemical calculations and first-principle simulations, we delved into the structural and electronic properties of BMPD as well as the interfacial adsorption mechanisms between the studied molecule and the iron surface. Full article

The authors studied the problem of naphthenate deposits in the oil and gas industry. Currently, there are few ways available to inhibit or dissolve naphthenate deposits in oil facilities. Naphthenate deposits can block pipelines and aggregate in other parts of the installation, i.e., in the separators. In Europe, the issue of deposition on oil rigs is commonly encountered in Norway and the United Kingdom, as well as in some African countries, i.e., Angola and Nigeria. Many tons of chemicals are used to combat naphthenate deposition, usually through inhibition, but also via the dissolution of the scale that precipitates over time. The presented work examines the characteristics of naphthenate fouling, historical ways to inhibit it, and current approaches to the problem, as well as the results of the laboratory testing of naphthenate inhibitors and solvents. The process of the naphthenate creation is as follows. When oil exhibits a high TAN (total acid number) and high content of salty water, naphthenate deposits can emerge via the reaction of naphthenic acids and metal salts (mostly calcium ones). Naphthenates are partially insoluble in water, and they usually float below the oil/water interface. The standard methods of naphthenate inhibition involve lowering the pH of the production water, which can result in serious problems, especially related to corrosion. This study addresses experiments conducted in the laboratory in Poland and on oil rigs in Angola and is based on contemporary knowledge and standards. The objective of this paper was to investigate the most suitable naphthenate inhibitors and solvents, as well as to undertake bottle tests of naphthenate inhibitors with a focus on the main indicators (water clarity, quality of separation surface, and clarity of oil). The use of citric and formic acids in this paper is a novelty, and it is compared with the results obtained with the more commonly used acetic acid, hydrochloric acid, and ABS acid. It was proven that formic acid can effectively inhibit and dissolve naphthenic deposits (99% efficiency of inhibition and 100% efficiency of dissolution). It was found that some acids used in naphthenate inhibition create more deposits than were originally present. Formic acid and ABS acid yielded significantly better results than other types. It is also here hypothesized that there are substances other than acids that can effectively remove naphthenate deposits, and the other novelty of this study is in the use of mutual solvents in the removal of naphthenate salts. Another important outcome is the finding that not only acids but also mutual solvents (EGMBE and isopropyl alcohol) can effectively remove naphthenate deposits. The test results show that formic acid dissolved all of the naphthenates, while citric acid had 97% efficacy, isopropyl alcohol had 95% efficacy, and EGMBE showed 94% efficacy. The impacts of commercial naphthenate inhibitors on the bottle test results and interfacial tension measurements were also investigated. It was shown that commercial naphthenate inhibitors can decrease the interfacial tension between oil and water by more than 30% when used at dosages of 400 ppm. Full article

The secreted phospholipases A2 (sPLA2s) play important roles both physiologically and pathologically, with their expression increasing significantly in diseases such as sepsis, inflammation, different cancers, glaucoma, obesity, Alzheimer’s disease and even COVID-19. The fact has led to a large-scale search for inhibitors of these enzymes. In total, several dozen promising molecules have been proposed, but not a single one has successfully passed clinical trials. The failures in clinical studies motivated in-depth fundamental studies of PLA2s. Here we review alternative ways to control sPLA2 activity, outside its catalytic site. The concept can be realized by preventing sPLA2 from attaching to the membrane surface; by binding to an external protein which blocks sPLA2 hydrolytic activity; by preventing sPLA2 from orienting properly on the membrane surface; and by preventing substrate binding to the enzyme, keeping the catalytic site unaltered. Evidence in the literature is summarized in the review with the aim to serve as a starting point for new types of sPLA2 inhibitors. Full article

The newly FDA-approved drug, Axitinib, is an effective therapy against RTKs, but it possesses severe adverse effects like hypertension, stomatitis, and dose-dependent toxicity. In order to ameliorate Axitinib’s downsides, the current study is expedited to search for energetically stable and optimized pharmacophore features of 14 curcumin (1,7-bis(4-hydroxy-3-methoxyphenyl)hepta-1,6-diene-3,5-dione) derivatives. The rationale behind the selection of curcumin derivatives is their reported anti-angiogenic and anti-cancer properties. Furthermore, they possessed a low molecular weight and a low toxicity profile. In the current investigation, the pharmacophore model-based drug design, facilitates the filtering of curcumin derivatives as VEGFR2 interfacial inhibitors. Initially, the Axitinib scaffold was used to build a pharmacophore query model against which curcumin derivatives were screened. Then, top hits from pharmacophore virtual screening were subjected to in-depth computational studies such as molecular docking, density functional theory (DFT) studies, molecular dynamics (MD) simulations, and ADMET property prediction. The findings of the current investigation revealed the substantial chemical reactivity of the compounds. Specifically, compounds S8, S11, and S14 produced potential molecular interactions against all four selected protein kinases. Docking scores of −41.48 and −29.88 kJ/mol for compounds S8 against VEGFR1 and VEGFR3, respectively, were excellent. Whereas compounds S11 and S14 demonstrated the highest inhibitory potential against ERBB and VEGFR2, with docking scores of −37.92 and −38.5 kJ/mol against ERBB and −41.2 and −46.5 kJ/mol against VEGFR-2, respectively. The results of the molecular docking studies were further correlated with the molecular dynamics simulation studies. Moreover, HYDE energy was calculated through SeeSAR analysis, and the safety profile of the compounds was predicted through ADME studies. Full article

Recent studies indicate that surfactants are a relatively new and effective class of corrosion inhibitors that almost entirely meet the criteria for a chemical to be used as an aqueous phase corrosion inhibitor. They possess the ideal hydrophilicity to hydrophobicity ratio, which is crucial for effective interfacial interactions. In this study, a coconut-based non-ionic surfactant, namely, coco monoethanolamide (CMEA), was investigated for corrosion inhibition behaviour against mild steel (MS) in 1 M HCl employing the experimental and computational techniques. The surface morphology was studied employing the scanning electron microscope (SEM), atomic force microscope (AFM), and contact measurements. The critical micelle concentration (CMC) was evaluated to be 0.556 mM and the surface tension corresponding to the CMC was 65.28 mN/m. CMEA manifests the best inhibition efficiency (η%) of 99.01% at 0.6163 mM (at 60 °C). CMEA performs as a mixed-type inhibitor and its adsorption at the MS/1 M HCl interface followed the Langmuir isotherm. The theoretical findings from density functional theory (DFT), Monte Carlo (MC), and molecular dynamics (MD) simulations accorded with the experimental findings. The MC simulation’s assessment of CMEA’s high adsorption energy (−185 Kcal/mol) proved that the CMEA efficiently and spontaneously adsorbs at the interface. Full article

Nanotechnology is a discipline of science and engineering that emphasizes developing, modifying, characterizing, and using nanoscale components in a variety of applications. Owing to their multiple advantages, including adhesion strength, surface hardness, long-term and extra-high-temperature corrosion resistance, improvement of interfacial behavior, etc., nanocoatings are efficiently utilized to minimize the influence of a corrosive environment. Additionally, nanocoatings are often applied in thinner and finer concentrations, allowing for greater versatility in instrumentation and reduced operating and maintenance costs. The exemplary physical coverage of the coated substrate is facilitated by the fine dimensions of nanomaterials and the significant density of their grounded boundaries. For instance, fabricated self-healing eco-sustainable corrosion inhibitors including PAC/CuONPs, PAC/Fe₃O₄NPs, and PAC/NiONPs, with uniform distributions and particulate sizes of 23, 10, and 43 nm, correspondingly, were effective in producing PAC/MONPs nanocomposites which exhibited IE% of 93.2, 88.1, 96.1, and 98.6% for carbon steel corrosion in 1M HCl at the optimum concentration of 250 ppm. Therefore, in this review, further steps are taken into the exploration of the significant corrosion-mitigation potential and applications of nanomaterial-based corrosion inhibitors and nano-modified coatings, including self-healing nanocoatings, natural source-based nanocoatings, metal/metallic ion-based nanocoatings, and carbon allotrope-based nanocoatings, to generate defensive film and protection against corrosion for several metals and alloys. These have been illuminated through the in-depth discussion on characterization techniques such as scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), atomic force microscopy (AFM), energy dispersive spectroscopy (EDS), etc. After providing a general summary of the various types of nanomaterials and their protective mechanisms in wide corrosive media, we subsequently present a viewpoint on challenges and future directions. Full article

In the present work, we present the superior corrosion inhibition properties of three plant-based products, Fraxinus excelsior (FEAE), Zingiber zerumbet (ZZAE), and Isatis tinctoria (ITAE), that efficiently inhibit the corrosion of mild steel in phosphoric acid. The anti-corrosion and adsorption characteristics were assessed using a combination of experimental and computational approaches. Weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy methods were used to evaluate the inhibitive performance of the inhibitors on the metal surface. Then, both DFT/DFTB calculations and molecular dynamic simulations were further adopted to investigate the interaction between organic inhibitor molecules and the metal surface. The protective layers assembled using the active constituents, such as carbonyl and hydroxyl groups, of the three plant-based products offer high electrochemical stability at high temperatures and robust protection against aggressive acidic solutions. All electrochemical measurements showed that the inhibition performance of extracts increased by increasing their concentration and improved in the following order: FEAE > ZZAE > ITAE. Further, these extracts worked as mixed-type inhibitors to block the anodic and cathodic active sites on the mild steel surface. Multi-level computational approaches revealed that FEAE is the most adsorbed inhibitor owing to its ability to provide electron lone pairs for electrophilic reactions. The experimental and theoretical results showed good agreement. These results indicate the possibility of replacing conventional compounds with natural substituted organic products in the fabrication of hybrid materials with effective anti-corrosion performance. Full article

The understanding of the mechanism of Topo I inhibition by organic ligands is a crucial source of information that has led to the design of more effective and safe pharmaceuticals in oncological chemotherapy. The vast number of inhibitors that have been studied in this respect over the last decades have enabled the creation of a concept of an ‘interfacial inhibitor’, thereby describing the machinery of Topo I inhibition. The central module of action of this machinery is the interface of a Topo I/DNA/inhibitor ternary complex. Most of the ‘interfacial inhibitors’ are primarily kinetic inhibitors that form molecular complexes with an “on–off” rate timing; therefore, all of the contacts between the inhibitor and both the enzyme and the DNA are essential to keep the complex stable and reduce the “off rate”. To test this hypothesis, we designed the compound using a C-9-(N-(2′-hydroxyethyl)amino)methyl substituent in an SN38 core, with a view that a flexible substituent may bind inside the nick of a model of the DNA and stabilize the complex, leading to a reduction in the “off rate” of a ligand in a potential ternary complex in vivo. Using docking analysis and molecular dynamics, free energy calculations on the level of the MM-PBSA and MM-GBSA model, here we presented the in silico-calculated structure of a ternary complex involving the studied compound 1. This confirmed our suggestion that compound 1 is situated in a groove of the nicked DNA model in a few conformations. The number of hydrogen bonds between the components of a ternary complex was established, which strengthens the complex and supports our view. The docking analysis and free energy calculations for the receptor structures which were obtained in the MD simulations of the ternary complex 1/DNA/Topo I show that the binding constant is stronger than it was for similar complexes with TPT, CPT, and SN38, which are commonly considered as strong Topo I inhibitors. The binary complex structure 1/DNA was calculated and compared with the experimental results of a complex that was in a solution. The analysis of the cross-peaks in NOESY spectra allowed us to assign the dipolar interactions between the given protons in the calculated structures. A DOSY experiment in the solution confirmed the strong binding of a ligand in a binary complex, having a K_a of 746 mM⁻¹, which was compared with a K_a of 3.78 mM⁻¹ for TPT. The MALDI-ToF MS showed the presence of the biohybrid, thus evidencing the occurrence of DNA alkylation by compound 1. Because of it having a strong molecular complex, alkylation is the most efficient way to reduce the “on–off” timing as it acts as a tool that causes the cog to brake in a working gear, and this is this activity we want to highlight in our contribution. Finally, the Topo I inhibition test showed a lower IC₅₀ of the studied compound than it did for CPT and SN38. Full article