Surface Modifier Research Articles

Study on the properties of biomass carbon quantum dots modified with diamine compounds and their application in iron ion detection

Diamine compounds are widely used as surface modifiers in the functionalization of carbon quantum dots, yet the effects of different diamines on the properties of carbon quantum dots remain unclear. In this study, carbon dots (P-CDs) were synthesized from peanut shell powder via a simple one-step microwave-assisted hydrothermal method. The surface of these carbon dots was modified through co-heating with ethylenediamine (EDA), o-phenylenediamine (OPD), m-phenylenediamine (MPD), and p-phenylenediamine (PPD). The effects of different diamines on the morphology and optical properties of P-CDs were systematically analyzed. The diamine-modified P-CDs exhibited varying sizes and similar crystal structures, with significantly enhanced fluorescence and quantum yields, reaching 35.2% for EDA-CDs. EDA-CDs and OPD-CDs demonstrated excitation-dependent emission behavior, while MPD-CDs and PPD-CDs did not. Based on EDA-CDs, a probe with high sensitivity for Fe3+ was developed, showing a good linear response within the Fe3+ concentration range of 20–100 μM and a detection limit of 2.768 μM. Additionally, the ion probe exhibited a recovery rate of 100.85% in both deionized and tap water, indicating good practical applicability. This study provides essential guidance for the nitrogen surface modification of biomass-derived carbon quantum dots and presents a promising Fe3+ probe with potential applications.

Facet engineering of Cu2O for efficient electrochemical glucose sensing.

Accurate monitoring glucose level is significant for human health management, especially in the prevention, diagnosis, and management of diabetes. Electrochemical quantification of glucose is a convenient and rapid detection method, and the crucial aspect in achieving great sensing performance lies in the selection and design of the electrode material. Among them, Cu2O, with highly catalysis ability, is commonly used as electrocatalyst in non-enzymatic glucose sensing. This feature has attracted great attentions for improving sensing performances by increasing exposed surface area and modifying with other active materials, but the intrinsic electrochemical activity of Cu2O is often diminished. In this work, we synthesized Cu2O cubes with exposed (100) faces, Cu2O octahedron with exposed (111) faces and Cu2O rhombic dodecahedron with exposed (110) faces of similar sizes to investigate the influence of expose facets on its glucose sensing performance. By employing the facets-regulation strategy, the anti-interference performance was largely improved by the Cu2O octahedron when compared with the Cu2O cube and the Cu2O rhombic dodecahedron, while the sensitivity and stability were also improved. Eventually, the Cu2O octahedron with exposed (111) faces based on glucose sensor displayed great practicability in human serum and the relative deviation was less than 3 % when compared with biochemical analyzer. Experimental, calculation and simulation result elucidate that Cu2O octahedron with exposed (111) faces, possessing stronger intrinsic electrochemical activity, comparatively favors the glucose adsorption, electron transfer and current density enhancement, rather than more active sites. This work focuses on the exploration of the intrinsic electrochemical activity of Cu2O and confirms that a facets-regulation strategy is an effective approach for boosting performance of non-enzymatic electrochemical sensors, especially for their sensitivity and selectivity. Moreover, it will lay the foundation for advancing the key field of precision medicine.

Biomedical Application of Bovine Type I Collagen and Its Fabricated Scaffolds: A Review

The transformation of waste into wealth remains a challenging yet essential endeavor, offering opportunities for efficient solid waste management. Type I collagen, abundant in bovine tendons, serves as a valuable feedstock for the extraction of this biomaterial. Derived from slaughterhouse solid waste, bovine type I collagen acts as a foundational biomaterial for tissue engineering and regenerative medicine. This fibrous protein-based eco-material features customizable properties, including biodegradability, mechanical resilience, and surface modifiability, making it a promising alternative to synthetic and biodegradable polymers. The design and development of bioactive scaffolds remain a significant challenge in regenerative medicine, tissue engineering, and drug delivery. Collagen-based biomaterial scaffolds, which mimic the extracellular matrix, are extensively utilized as templates for tissue regeneration in biomedical applications. These scaffolds enhance wound healing and facilitate the maturation of collagen fibers, promoting the rapid formation of mature, aligned tissue at wound sites. This review provides a comprehensive analysis of the biomedical applications of collagen-based biomaterials, including their isolation and purification from bovine tendons, characterization, scaffold fabrication, ciprofloxacin/Triphala conjugation into scaffolds, biochemical and histological wound healing investigations, drug delivery, and cell culture applications. Recent advancements in chemically modified collagen and collagen-biodegradable polymer composites with controlled drug delivery for wound treatment, as well as collagen-based diffusion membranes for prolonged drug release, are also discussed.

Pickering Emulsions: Role of Particle Wettability and Adhesive Force on Droplet Bridging.

This study demonstrates the engineering of bridged Pickering emulsion (PE) gels by tuning the particle position at the interface and adhesive forces. This is achieved through controlled surface modification of hematite particles using oleic acid in a water-decane system. Microscopy observations revealed that the droplets are stabilized through a bridging mechanism, where oil droplets are connected by a shared monolayer of particles, with an intervening water layer between them. The experimental observations reveal that the concentration of oleic acid affects both the position of particles with respect to the interface (wettability) and adhesive forces, leading to the formation of emulsions with bridged droplets at specific oleic acid concentration ranges. To investigate this, the particle position at the interface and the strength of adhesive force are measured as a function of oleic acid concentration by direct visualization and droplet stretching technique, respectively. These studies confirm that at low oleic acid concentrations, the particle position favors the bridging, as particles are preferentially wettable by the continuous phase (water) but adhesive forces are not strong. Thus, this condition promotes the formation of oil-in-water emulsions without bridging. While, at higher oleic acid concentrations, the position of particles with respect to the interface hinders bridging, despite sufficient adhesive forces, because the particle surface becomes preferentially wettable by dispersed phase (oil), thereby supporting the inversion of emulsions. Therefore, a precise amount of oleic acid is necessary to achieve stable bridging with both factors contributing to the bridge formation. Further, the versatility of the process is illustrated by using different types of oil and particle surface modifiers. In all of the cases, stable emulsions are obtained by droplet bridging at a precise concentration of the modifier. The effect of the particle concentration and water-to-decane volume ratio on the stability of these emulsions is also studied. These emulsions show remarkable stability under undisturbed conditions due to gel-like nature despite the droplets being partially covered with particles. Moreover, after such emulsions are destabilized by external stimuli, emulsions with similar features can be readily and reversibly formed.

Polymeric Nanoparticles: Targeted Delivery in Breast Cancer - A Review

Background: Breast cancer is one of the most prevalent cancers affecting the female population worldwide. It is a highly heterogeneous disease mainly classified into three subtypes based on the status of the molecular markers for the hormones (estrogen and progesterone) and epidermal growth factor (HER-2) receptors. Hormone receptor positive breast cancer shows a good prognosis, while tumors that do not show any of these receptors (triple negative breast cancer) are highly invasive. Despite all the conventional therapies for the treatment of breast cancer, it remains the leading cause of cancer deaths of women worldwide. Objective: Chemical grafting of nanoparticles (NPs) with polymers and surface modifiers as a targeted ligand can become an alternative for active targeting. Hence, these polymeric NPs can control drug release with pH-responsive stimuli, and the high selectivity of these NPs allows them to accumulate more inside the cancer cells that overexpress these receptors, leaving normal cells unaffected. Methods: Formulation incorporates various polymers, solvents drug, and stabilizing agents in the aqueous phase. Various techniques discussed in this review are employed for synthesis, resulting in a dry NP formulation. Results: In this context, we shall discuss the development of NPs against distinct forms of cancer malignancies. From here, we know that polymeric NPs can produce a system with good characteristics, effectiveness, and active targeting of different cancer cells. Conclusion: This system is a striking candidate for the targeted drug delivery for cancer therapy, anticipating that NPs could be further developed for various breast cancer therapy applications.

The Study of Tunable Excitation Independent and Dependent Photoluminescence Behaviour of P-Functionalized Carbon Dots

In this article, excitation independent and dependent fluorescence properties of surface functionalized carbon dots were studied. The samples were synthesized using a biomass derived Indian gooseberry as carbon precursor via microwave irradiation technique. Concentrated phosphonic acid is utilized as a surface passivator for carbon dots. The formation of spherical carbon dots in the size range of 6 to 12 nm was shown by transmission electron microscopy images. Raman and Fourier transform IR spectroscopies suggest the creation of highly disordered sp3carbon atoms including presence of surface functional groups and interaction of phosphorus with surface of carbon core. From the UV-visible absorption study, absorbance bands at 231 nm and 283 nm attributed to π-π* molecular transitions from carbon core are found. From the photoluminescence measurements, both excitation independent and excitation dependent tunable fluorescence is obtained from ultraviolet to visible (yellow) region of light respectively. The involvement of carbon core electronic states and surface modifier states are responsible for the origin of luminescence and their distinguished nature. The mechanism is discussed and emitted colour are confirmed by CIE plot. The relative quantum yield of the P-functionalized carbon dots is found to be 18.9% with reference to quinine sulfate. The fluorescence in ultra-violet and visible regions is applicable for bioimaging and potential antimicrobial activities.

Stereolithography 3D printing gyroid triply periodic minimal surface vitrified bond diamond grinding wheel

The pores of vitrified bond diamond grinding wheel play a key role in the grinding process. However, uneven pore distribution and low porosity affect the grinding performance of the wheel significantly. Stereolithography based additive manufacturing provides an effective method to fabricate vitrified bond diamond grinding wheels with a uniform distribution and an interconnected pore structure. The key to high-performance grinding wheel via stereolithography 3D printing lies in the preparation of the slurry with high solid loading, low viscosity and uniform stability. In this study, the dispersion and stability of vitrified bond and diamond slurries were investigated systematically. The effects of resin monomers, surface modifiers, and solid loading on the dispersion, rheological behavior and stability of slurries were studied in detail. Finally, an optimal vitrified bond and diamond slurry for stereolithography based additive manufacturing was obtained, and complex-shaped gyroid triply periodic minimal surface grinding wheel were fabricated. By grinding the SiC ceramics, the material removal rate, grinding temperature, and surface roughness were compared to those achieved using a conventional solid structure grinding wheel. The results show that the gyroid porous grinding wheel can achieve better surface roughness and lower the grinding temperature.

Nanoparticle biosensors for cardiovascular disease detection.

Early detection and management of cardiovascular diseases (CVDs) are crucial for patient survival and long-term health. CVD biomarkers such as cardiac Troponin-I (cTnI), N-terminal pro-brain natriuretic peptide (NT-proBNP), creatine kinase MB (CK-MB), Galectin-3 (Gal-3), etc are released into the circulation following heart muscle injury, ie, acute myocardial infarction (AMI). Biosensor technology including the use of nanoparticles can be designed to target specific biomarkers associated with CVD, enabling early detection and more rapid intervention to decrease morbidity and mortality. To date, with the combination of developed nanoparticles, several optical and electrochemical-based biosensors have successfully been used detection of CVD biomarkers. Nanomaterials, when introduced as the modifiers of sensor surfaces like electrodes and gold chips, can result in the more comprehensive and more effective immobilization of capture molecules, ie, antibodies, aptamers and other ligands, due to their large surface area. In recent years, inorganic nanoparticles have regularly been used in the production of biosensors mostly due to their excellent response intensification, adaptable functionalization chemistry, shape control, good biocompatibility, and great stability. In this review, we discuss the application of different kinds of nanoparticles for the sensitive and specific detection of CVD biomarkers.

Reprint of: M1 macrophage-targeted curcumin nanocrystals with l-arginine-modified for acute lung injury by inhalation.

Acute Lung Injury/Acute Respiratory Distress Syndrome (ALI/ARDS) with clinical manifestations of respiratory distress and hypoxemia remains a significant cause of respiratory failure, boasting a persistently high incidence and mortality rate. Given the central role of M1 macrophages in the pathogenesis of acute lung injury (ALI), this study utilized the anti-inflammatory agent curcumin as a model drug. l-arginine (L-Arg) was employed as a targeting ligand, and chitosan was initially modified with l-arginine. Subsequently, it was utilized as a surface modifier to prepare inhalable nano-crystals loaded with curcumin (Arg-CS-Cur), aiming for specific targeting of pulmonary M1 macrophages. Compared with unmodified chitosan-curcumin nanocrystals (CS-Cur), Arg-CS-Cur exhibited higher uptake in vitro by M1 macrophages, as evidenced by flow cytometry showing the highest fluorescence intensity in the Arg-CS-Cur group (P < 0.01). In vivo accumulation was greater in inflamed lung tissues, as indicated by small animal imaging demonstrating higher lung fluorescence intensity in the DiR-Arg-CS-Cur group compared to the DiR-CS-Cur group in the rat ALI model (P < 0.05), peaking at 12 h. Moreover, Arg-CS-Cur demonstrated enhanced therapeutic effects in both LPS-induced RAW264.7 cells and ALI rat models. Specifically, treatment with Arg-CS-Cur significantly suppressed NO release and levels of TNF-α and IL-6 in RAW264.7 cells (p < 0.01), while in ALI rat models, expression levels of TNF-α and IL-6 in lung tissues were significantly lower than those in the model group (P < 0.01). Furthermore, lung tissue damage was significantly reduced, with histological scores significantly lower than those in the CS-Cur group (P < 0.01). In conclusion, these findings underscore the targeting potential of l-arginine-modified nanocrystals, which effectively enhance curcumin concentration in inflammatory environments by selectively targeting M1 macrophages. This study thus introduces novel perspectives and theoretical support for the development of targeted therapeutic interventions for acute inflammatory lung diseases, including ALI/ARDS.

Complexed hyaluronic acid-based nanoparticles in cancer therapy and diagnosis: Research trends by natural language processing.

Hyaluronic acid (HA) is a popular surface modifier in targeted cancer delivery due to its receptor-binding abilities. However, HA alone faces limitations in lipid solubility, biocompatibility, and cell internalization, making it less effective as a standalone delivery system. This comprehensive study aimed to explore a dynamic landscape of complexation in HA-based nanoparticles in cancer therapy, examining diverse aspects from influential modifiers to emerging trends in cancer diagnostics. We discovered that certain active substances, such as 5-aminolevulinic acid, adamantane, and protamine, have been on trend in terms of their usage over the past decade. Dextran, streptavidin, and catechol emerge as intriguing conjugates for HA, coupled with nanostar, quantum dots, and nanoprobe structures for optimal drug delivery and diagnostics. Strategies like hypoxic conditioning, dual responsiveness, and pulse laser activation enhance controlled release, targeted delivery, and real-time diagnostic techniques like ultrasound imaging and X-ray computed tomography (X-ray CT). Based on our findings, conventional bibliometric tools fail to highlight relevant topics in this area, instead producing merely abstract and broad-meaning keywords. Extraction using Named Entity Recognition and topic search with Latent Dirichlet Allocation successfully revealed five representative topics with the ability to exclude irrelevant keywords. A shift in research focuses from optimizing chemical toxicity to particular targeting tactics and precise release mechanisms is evident. These findings reflect the dynamic landscape of HA-based nanoparticle research in cancer therapy, emphasizing advancements in targeted drug delivery, therapeutic efficacy, and multimodal diagnostic approaches to improve overall patient outcomes.

(Invited) Self-Recovery of Photodegraded CsPbBr3 Perovskite Nanocrystals and Problems By Irreversible Damage

CsPbBr3 perovskite nanocrystals (NCs) synthesized by a typical hot injection method are adsorbed with surface modifiers. The authors have investigated photodegradation and self-recovery phenomena due to photo-induced desorption by excitation light irradiation and re-adsorption of the surface modifiers in the dark, respectively [1-4]. These phenomena occurred when a dry solid sample of NCs was placed in a sample holder covered with a glass plate to shut out the atmosphere. On the other hand, the dried NCs exposed to the air did not show the self-recovery after photodegradation. This was due to irreversible degradation caused by surface oxidation by atmospheric oxygen. When the dried NCs were covered with a resin film instead of a glass plate, the resin with lower gas barrier properties did not prevent oxidation. However, the use of a resin with higher gas barrier properties confirmed the occurrence of photodegradation and subsequent self-recovery. The authors will present recent results including experiments on nanocomposite films of the NCs dispersed in resin.References K. Kidokoro, Y. Iso, T. Isobe, J. Mater. Chem. C, 7, 8546 (2019).K. Miyashita, K. Kidokoro, Y. Iso, T. Isobe, ACS Appl. Nano Mater., 4, 12600 (2021).I. Enomoto, Y. Iso, T. Isobe, J. Mater. Chem. C, 10, 102 (2021).K. Kano, Y. Iso, T. Isobe, ECS J. Solid State Sci. Technol., 12, 056003 (2023). Figure 1

Enhanced Mass Transportation for the Oxygen Evolution Reaction in Flexible Mesoporous Hydrogel Electrodes

Water electrolysis is of great importance for the hydrogen production from renewable energy. The efficiency of water electrolysis depends highly on the performance of anodes because of the high overpotential of the oxygen evolution reaction (OER). Mesoporous electrodes with high surface area and relatively small pore size (2-50 nm) have attracted much attention as highly active OER electrodes; however, the mass transportation of generated oxygen molecules and hydroxide ions in mesopores often limit the OER current density.In this study, we propose a novel class of materials, namely flexible mesoporous hydrogel electrodes which consist of assemblies of CoOOH nanosheets. Flexible mesoporous hydrogel electrodes were prepared by electrochemical deposition of cobalt hydroxide nanosheets modified with tris(hydroxymethyl)aminomethane (depicted as Co-ns [1]) on nickel substrates. Co-ns formed a house-of-cards assembly, having characteristics of hydrogels, during the deposition process. The surface modifying group of Co-ns was anodically decomposed and Co-ns was transformed into CoOOH nanosheets. Because of the weak connections among CoOOH nanosheets the resultant assemblies provided flexible mesoporous frameworks.The flexible mesoporous electrodes with different thicknesses (4-37 μm) were prepared, changing the deposition time. The porosity of the flexible mesoporous electrodes were estimated to be approximately 97% because of the very thin thickness of the CoOOH nanosheets. Rigid mesoporous electrodes with Co3O4 frameworks with different thicknesses (11-60 μm) were also prepared by dip-coating method, using Pluronic F127 as a template. The porosity of the rigid mesoporous electrodes was approximately 78%. The electrochemical tests were performed in a three electrode cell at 30 ºC.The OER polarization curves of the flexible mesoporous electrodes and the rigid mesoporous electrodes in 1.0 M KOH electrolyte are shown in the Figure 1. The OER current densities of the rigid mesoporous electrodes depend quantitatively on the thickness of the films at 1.50 V vs. RHE, though the current densities became independent of the thickness of the films at 1.60 V vs. RHE. On the other hand, the OER current densities of the flexible mesoporous electrodes depend quantitatively on the thickness of the films at wide potential region, even at 1.60 V vs. RHE, indicating that the high mass transport ability of generated oxygen molecules and hydroxide ions in the mesopores.In conventional rigid mesoporous electrodes, oxygen bubbles should form within mesopores with defects, i.e. large nanospace and cracks, and the generated bubbles plug the mass transport paths. The flexible mesoporous hydrogel electrodes are expected to have defect-less mesoporous structures because they can change the mesoporous structures flexibly to reduce defects, and defects can be self-healed once they are formed. It is also expected that the flexible frameworks change their mesoporous structure to optimize the mass transportation path during OER.In conclusion, novel mesoporous hydrogel electrodes were prepared for the first time by the electrochemical deposition of Co-ns. The flexible mesoporous hydrogel electrodes exhibited high OER performance, depending on the thickness of the films quantitatively at high current density region. Flexible mesoporous hydrogel electrodes are promising as novel types of electrodes to improve the efficiency of water electrolysis. This work was supported by the JSPS KAKENHI (grant number 24K01580).

Silane-free superhydrophobic coatings from ball-milled nanosand using eco-friendly polymeric modifiers

A simple immersion method is proposed to develop durable superhydrophobic cotton fabric from low-cost, fluorine and silane-free eco-friendly materials, to address the growing environmental concerns led by hazardous surface modifiers. Herein, silica sand nanoparticles (SS NPs) were synthesized by mechanical ball-milling approach, from a least reported silica abundant natural source, Cherthala sand. Cherthala a small town in the Alappuzha district of Kerala is noted for its high quality sand with 96.5% silica. The synthesis of SS NPs was optimized based on ball-to-powder weight ratio (BPR) and milling time using Central Composite Design of response surface methodology. Minimum crystallite size (∼26 nm) and maximum turbidity (355 NTU) were obtained for the trial loaded with 20:1 BPR and processed for 10 hours. In a traditional nano-coating approach, the milled SS NP was employed as the roughness-enhancer along with polymeric binder for adhesion; silicone oil and stearic acid to lower the surface energy. The standardized coating mixture exhibited maximum water contact angle 158.9 ± 7.6°, long-term water repellency, chemical stability after 12 hours standing in acidic and alkaline pH and more than five detergent washing cycles. The coated fabrics were resilient to O2-plasma, UV-irradiation and adhesive peel test. The study also presented the practical scope of the developed eco-friendly coatings for oil-water separation and in wearable smart textiles. Thus, the present work offers a scalable sustainable route to develop silica NP-based functional textiles with same comfort, touch-proof, and breathability.

Dual‐Site Anchors Enabling Vertical Molecular Orientation for Efficient All‐Perovskite Tandem Solar Cells

AbstractAll‐perovskite tandem solar cells (TSCs) are gaining increasing attention due to their potential to surpass the efficiency limit of single‐junction solar cells. However, as the bottom low‐bandgap subcells, tin‐lead (Sn‐Pb) perovskites suffer from severe nonradiative recombination at the interfaces due to their susceptibility to oxidation and poor crystalline morphology. Here a surface modifier 4‐(trifluoromethyl)benzhydrazide (TFH) is reported to construct a reductive chemical environment on the surface of perovskite films and protect them from water and oxygen erosion. TFH anchors onto the Sn‐Pb perovskites in a preferred vertical orientation through dual‐site binding, forming interface dipoles that facilitate charge extraction. The reductive hydrazine groups of TFH can effectively inhibit the oxidation of Sn2+ and I−, thereby reducing the defect density and energy disorder of Sn─Pb perovskites. Consequently, the TFH‐treated devices achieved a champion PCE of 22.88%, maintaining over 93% of the initial efficiency after continuous one‐sun illumination for 500 h. Combined with a 1.79 eV wide‐bandgap subcell, it has demonstrated a PCE of 28.17% in all‐perovskite TSCs.

Impact of Optimal Silane Concentration on the Rheological Properties and 3D Printing Performance of Al2O3-Acrylate Composite Slurries.

In this study, 3-trimethoxy-silylpropane-1-thiol (MPTMS) was used as a surface modifier for Al2O3 powder to systematically analyze the effects of MPTMS concentration on the rheological properties, photocuring characteristics, and 3D printing performance of photocurable composite slurries. MPTMS concentration significantly influenced the rheological behavior of the slurry. Slurries containing 2 wt.% and 5 wt.% MPTMS exhibited a wide linear viscoelastic range (LVR). However, at concentrations of 10 wt.% and 20 wt.%, the LVR range narrowed, which led to reduced dispersion stability. In dispersion stability tests, the slurry with 2 wt.% MPTMS showed the most stable dispersion, while the 5 wt.% MPTMS concentration exhibited the highest photocuring rate. In 3D printing experiments, the 5 wt.% MPTMS concentration resulted in the most stable printed structures, whereas printing failures occurred with the 2 wt.% concentration. At 10 wt.% and 20 wt.%, internal cracking was observed, leading to structural defects. In conclusion, MPTMS forms silane bonds on the Al2O3 surface, significantly impacting the stability, rheological properties, and printing quality of Al2O3-acrylate composite slurries. An MPTMS concentration of 5 wt.% was found to be optimal, contributing to the formation of stable and robust structures.

Preparation of Diisooctyl Phosphate‐Modified Ultra‐Small Zinc Oxide Nanoparticle and Investigation of Its Tribological Properties as Additive in Alkylnaphthalene

ABSTRACTZnO nanoparticle surface‐modified by diisooctyl phosphate (P204) was prepared by liquid‐phase in situ surface modification technique with zinc acetate as the raw material, P204 as the modifier and anhydrous ethanol as the solvent. The morphology and microstructure of the P204‐ZnO nanoparticle were characterised by transmission electron microscopy, X‐ray diffraction and Fourier transform infrared spectrometry. Its thermal stability was evaluated by thermogravimetric analysis; and its tribological properties as the additive in alkylnaphthalene were evaluated with an SRV‐5 friction and wear tester in reciprocal sliding mode. The results show that the as‐prepared P204‐ZnO nanoparticle has an average particle size of about 4 nm and a P204 content of about 42% (mass fraction); and the surface modifier is grafted onto the surface of ZnO nanoparticle by physical adsorption. With a mass fraction of 0.5% in alkylnaphthalene base oil, P204‐ZnO nano‐additive can mildly reduce the friction coefficient and drastically reduce the wear rate of the steel–steel sliding pair. This is due to the formation of the composite tribofilm via the adsorption and deposition of the nano‐additive on rubbed steel surfaces as well as the tribochemical reactions of the modifier P204 yielding phosphate and of steel substrate yielding iron oxides. The as‐formed composite tribofilm with a thickness of about 20 nm, consisting of phosphate and iron oxides as the binder as well as deposited ZnO nanoparticle as the filling phase, is responsible for the excellent friction‐reducing and antiwear abilities of P204‐ZnO nano‐additive for the steel sliding contact.

Nano-Pd/SiO2 aerogel catalyst prepared via ambient pressure drying process using perlite powder in hydrogenation and cross-coupling reactions

Perlite, a cheap silica source with abundant reserves in countries such as Türkiye, China, and Greece, was used to produce nano Pd-doped silica aerogel powder for the first time in this study. The microstructure and morphology of the prepared silica aerogel powder were examined using SEM, FE-SEM, and TEM. The phases of the silica aerogel powders were analyzed via XRD (X-ray Diffraction) technique. The chemical bonding of the surface modifier with aerogels was analyzed by Fourier transform infrared spectroscopy (FTIR, Spectrum RX-1, Perkin Elmer). Surface areas, pore volumes, distributions, and particle sizes of the alumina-silica-based aerogel powders with a porous structure were measured using a Micromeritics/ASAP 2020 brand BET (Brunauer, Emmet, and Teller) device in a liquid nitrogen gas environment at 77K.The efficiency of this nano Pd-doped silica aerogel powder was investigated as a heterogeneous catalyst for well-known transformations in organic synthesis, such as alkene hydrogenation and cross-linking reactions. The results indicated that the developed method is chemoselective, reducing only carbon-carbon multiple bonds without affecting C-N or C-O multiple bonds, such as carbonyl and nitrile. The effectiveness of the newly developed catalyst was also investigated in Heck and Suzuki-Miyaura reactions, yielding the targeted products with high efficiency.Thus, an inexpensive, economical, and environmentally friendly method has been developed that is potentially applicable in the hydrogenation and cross-coupling reactions of alkenes.

On the mechanism for work function change of gold electrodes by ultrathin polyethyleneimine (PEI) films: Effect of molecular order.

Polyethyleneimine (PEI) is a widely used cationic polyelectrolyte. In organic electronics, it is a universal surface modifier for shifting the electrode work function (Φ) and improving charge injection into electronic devices. This effect may depend on the conformation and dipolar order of the PEI ultrathin film, but their detailed experimental evaluation has not yet been reported. Thus, we used sum-frequency generation (SFG) spectroscopy to probe the net orientation of polar groups of PEI films on glass and gold. The films were fabricated by spin-coating from alcoholic solutions or by dip-coating from aqueous solutions of various pH values, with both branched (b-PEI) and linear (l-PEI) structures. The obtained SFG spectra and atomic force microscopy (AFM) images indicated that the conformational ordering of the PEI layers increases over the period of 14 days after fabrication, being slightly more pronounced for l-PEI vs b-PEI, and for dip-coating vs spin coating fabrication. Furthermore, both the pH of the dip-coating solutions and the substrate nature influence the final morphology and order of the adsorbed films. On glass, they are optimized at an intermediate pH 5, while on gold, the greatest homogeneity is observed at pH 2 and the largest dipolar order is observed at pH 10. The pH dependence of changes in the work function of gold by PEI (|ΔΦ|) suggests that the electronic contribution is dominant. Nevertheless, the evolution of the PEI dipolar ordering was accompanied by small variations of |ΔΦ|, suggesting that it does have a significant contribution, especially at conditions for which the electronic contribution is reduced.

Study on the water and mold resistance of ZnO/polyurethane superhydrophobic coating on circuit boards

In this work, superhydrophobic coatings were prepared on circuit boards based on the susceptibility of circuit boards to harsh environments such as humidity and mold adhesion, leading to reduced service life. Firstly, cetyltrimethoxysilane and γaminopropyltriethoxysilane were used to modify zinc oxide nanoparticles with different particle sizes. Then polyurethane and modified nanoparticles were successively sprayed on the circuit boards with a spraying process, and the superhydrophobic coatings were finally produced. The impact of the zinc oxide mass ratio with different particle sizes, silane coupling agent content, and surface modifier content on the hydrophobicity of the coatings were investigated. The results show that when the mass ratio of zinc oxide (30nm) to zinc oxide (90nm) is 1:1, the silane coupling agent content is 12‰. The surface modifier content is 12‰, the hydrophobicity of the coating is the best, and its CA can be up to 169.5°, and its SA can be up to 2.8°. It exhibits good protection of circuit boards in the tests of adhesion, acid, and alkali corrosion resistance, self-cleaning performance, and anti-mold performance. Performance, so that the coating is in the future field of electronic equipment applications.

Experimental Investigation of the Combustion Characteristics and Thermal Hazards of Methylsilyl-Modified Silica Aerogels.

The thermal safety of hydrophobic silica aerogels (SAs) is essential to thermal insulation applications. Herein, trimethylchlorosilane (TMCS), dimethyldichlorosilane (DMDCS), and methyltrichlorosilane (MTCS) were employed as surface modifiers to prepare three different methylsilyl-modified SAs (i.e., TSA, DSA, and MSA) and their combustion characteristics and thermal hazards were experimentally studied in detail. The cone calorimeter test found that the three SAs have similar combustion processes and the variations in ignition time and fire spread rate with the heat flux obey simple logarithmic and linear relationships, respectively. It further found that TSA has the most methylsilyl groups on silica skeletons and thus has the largest heat release, followed by DSA and MSA in turn, implying that TSA has the greatest fire hazard among the three SAs. These results further demonstrate that the type and quantity of methylsilyl groups on the skeletons of SAs significantly affect the thermal hazard of methylsilyl-modified SAs. In addition, the combustion mechanism of the methylsilyl-modified SAs is discussed. In total, this work experimentally studies the combustion characteristics of methylsilyl-modified SAs and compares their thermal hazards, clarifying the potential fire risk of methylsilyl-modified SAs in practical thermal insulation applications.