Contact Angle Test Research Articles

Preparation and characterization study of composite dust suppressant based on xanthan gum

To address the critical issue of particulate matter emitted from mining operations, which poses a significant risk to human health, production safety, and the environment, a novel dust suppressant based on xanthan gum (XTG) as a coalescing agent was introduced in this study. The formulation innovatively combines anionic surfactants SDS (Sodium dodecyl sulfate) and SDBS (Sodium dodecyl benzene sulfonate) as well as nonionic surfactants OP-10, Tween-20 (Polyoxyethylene anhydrous sorbitan monolaurate) and Tween-80 (Polyoxyethylene anhydrous sorbitan monooleate) with 0.05% XTG to enhance the wettability of the solution. Considering the economy and practicality, 0.05% OP-10 + 0.05% XTG (M-OX) was finally selected as the optimal dust suppressant formulation. Through a series of experiments, including surface tension, contact angle, sedimentation, pH value, water retention, and wind erosion resistance tests, we proved that M-OX, with a pH value of 8.03, has the least impact on the environment, has better water retention, and has a significant dust suppression effect. The curing layer formed by M-OX can adapt to complex weather, maintains its integrity after rain and wind erosion, and exhibits excellent rain and wind erosion resistance. This study provides an environmentally friendly and effective dust suppression solution for surface coal mines with significant social and economic benefits.

Polyvinyl Alcohol Composite with Enhanced Mechanical and Biological Properties for Soft Tissue Application

Polyvinyl alcohol (PVA) is a non-toxic, thermoplastic polymer that is completely biodegradable. So it is based on many composite materials for biomedical applications. In this study, various specimens were prepared by solvent casting method and then tested by tensile, FTIR, contact angle, SEM, antibacterial and cytotoxicity test. The results obtained showed the tensile strength decreased with the addition of PEG and then tended to improve after the addition of collagen and nano-titanium oxide. The wettability test shows the prepared specimens changed from hydrophobic to hydrophilic properties. The biological properties explained that the prepared composite had a better antibacterial effect and none of the samples had a toxic effect.

Silica modified by SiO2/silicone fluoroethylene acrylate emulsion superhydrophobic coating for electromagnetic wire study on the properties of the composite insulating layer

Abstract In this paper, a silicone-containing fluoroethylene acrylate emulsion was synthesized through emulsion polymerization, and a superhydrophobic coating was prepared by compounding it with modified SiO2 particles. The micromorphology, composition, and hydrophobic properties of the coating surface were analyzed using scanning electron microscopy, Fourier-transform infrared spectroscopy, x-ray diffraction, x-ray photoelectron spectroscopy, and water contact angle tests. The results revealed the presence of numerous micro-nanostructures on the coating surface, with a water contact angle of 161 ± 0.5°, indicating the characteristics of a superhydrophobic coating. A superhydrophobic composite insulating layer was created by modifying the quartz fiber insulating layer of electromagnetic wire with the superhydrophobic coating. The quartz fiber-insulated electromagnetic wire, treated with moisture, was evaluated for its insulation and breakdown voltage performance. The findings demonstrate that the superhydrophobic coating significantly reduces moisture absorption in quartz fiber, and the electromagnetic wire, even after moisture treatment, maintains excellent insulation and high breakdown strength, indicating promising applications in the field of electromagnetic wire insulation materials.

A surface engineering strategy for the stabilization of zinc metal anodes with montmorillonite layers toward long-life rechargeable aqueous zinc ion batteries

Rechargeable aqueous zinc-ion batteries (AZIBs) exhibit appreciable potential in the domain of electrochemical energy storage. However, there are serious challenges for AZIBs, for instance zinc dendrite growth, hydrogen evolution reaction (HER), and corrosion side reactions. Herein, we propose a surface engineering modification strategy for coating the montmorillonite (MMT) layer onto the surface of the Zn anode to tackle these issues, thereby achieving high cycling stability for rechargeable AZIBs. The results reveal that the MMT layer on the surface of the Zn anode is able to provide ordered zincophilic channels for zinc ions migration, facilitating the reaction kinetics of zinc ions. Density functional theory (DFT) calculations and water contact angle (CA) tests prove that MMT@Zn anode exhibits superior adsorption capacity for Zn2+ and better hydrophobicity than the bare Zn anode, thereby achieving excellent cycling stability. Moreover, the MMT@Zn||MMT@Zn symmetric cell holds the stable cycling over 5600 h at 0.5 mA cm−2 and 0.125 mA h cm−2, even exceeding 1800 h long cycling under harsh conditions of 5 mA cm−2 and 1.25 mA h cm−2. The MMT@Zn||V2O5 full cell reaches over 3000 cycles at 2 A g−1 with excellent rate capability. Therefore, this surface engineering modification strategy for enhancing the electrochemical performance of AZIBs represents a promising application.

Amphiphilic poly(methacryloxyethyl sulfobetaine)-block-poly(ε-caprolactone) blended polyvinyl chloride plastics: Study on the Relationship between molecular structure and antibiofouling properties

The blending of amphiphilic copolymers with plastics is an important method for preparing antibiofouling medical plastics. However, enhancing the enrichment of amphiphilic copolymers on the plastic surface, thereby improving the antibiofouling performance of the plastics remain challenging tasks. Herein, we designed and synthesized a series of amphphilic copolymers, denoted as PSB-b-nPCL. These copolymers possess similar chemical compositions but exhibit distinct topological structures. Antibiofouling flexible polyvinyl chloride (PVC) films were prepared by blending PSB-b-nPCL with PVC. These films showed excellent mechanical and thermal properties. X-ray photoelectron spectroscopy, water contact angle and hydration capacity tests demonstrated that PSB-b-nPCL which bearing more PCL blocks were more prone to migrating to the film surface, thereby enhancing the film’s hydrophilicity. Furthermore, anti-protein adsorption, anti-bacterial and anti-platelet adhesion properties of the films were investigated. It was found that topological structure can obviously affect the antibiofouling performance of films. Specifically, films blended with PSB-b-nPCL containing more PCL blocks exhibited superior performance. The optimal blended film achieved a reduction of 96.4% in bovine albumin adsorption, 82% in platelet adhesion, and nearly complete inhibition of bacterial adhesion. We anticipate that the strategy presented in this work will pave a new path for the development of high performance antibiofouling plastics.

Enhancing Water Barriers by Protein-Based Surface Treatments for Cellulose-Based Materials

ABSTRACT The global packaging sector has grown consistently, and the use of sustainable materials, including recycled and biodegradable products, is expected to rise. This study focuses on the potential of producing barriers for water and water in moist air (water vapor) from proteins to protect cellulosic materials. Owing to the specific requirements of packaging materials, the main subject of this research was their barrier and strength properties. The scope of this work includes selecting components and their physicochemical treatment to produce functionalized coatings on sprayed paper and pure films, as well as film-coated samples (paper laminated with film). The following tests were used to estimate the hydrophobic, hygroscopic, and strength properties: Cobb absorption, contact angle testing, dynamic vapor sorption, and dynamic mechanical analysis. In most cases, the spray-coated paper and film-coated samples absorbed less liquid water than untreated paper. Wheat gluten protein was the most effective water barrier. In all variants, the vapor sorption, desorption, and hysteresis effects (or the lack thereof) showed significant differences compared to those of cellulosic materials. All variants of the spray-coated and film-coated samples in the dynamic mechanical analysis showed an increase in the strength properties of the samples in comparison to the untreated paper. The increased humidity caused a significant loss in the mechanical properties of all variants, exceeding the strength loss of the untreated control samples.

Epoxy resin‐based biomass composites based on modified corn stalks: Preparation, properties, and toughening mechanism

AbstractIn this study, a series of sustainable eco‐friendly epoxy resin (EP)‐based biomass composites (DSA‐CS/EP) were prepared using bisphenol A EP as matrix, 2‐methylimidazole as curing agent, and corn stalk (CS) esterified with dodecene succinic anhydride (DSA) as filler. The static contact angle test results showed that the hydrophobicity of CS after esterification with DSA (DSA‐CS) was enhanced, which results in the compatibility of DSA‐CS with EP matrix was improved. And then, the DSA‐CSs were dispersed homogeneously in the matrix without agglomerating. The morphology and properties of the biomass composites were studied and analyzed in order to elucidate the toughening mechanism of CS and DSA‐CS. When the content of DSA‐CS is 15 wt%, the tensile strength and impact strength of DSA‐CS/EP reached a maximum value of 30.39 MPa and 3.34 KJ/m2, which were increased by 128.49% and 81.52% compared with pure EP. Finally, it is deduced that the possible toughening mechanism is that DSA‐CS can not only share part of the external stress but also a mutual solute region is formed between DSA‐CS and EP matrix.Highlights Corn stalks esterified by DSA were used as reinforcement filler for epoxy resin. The cellulose in CS was mainly esterified. The tensile and impact strength of DSA‐CS 15/EP reached a maximum value. A mutual solute region is formed between filler and matrix.

Unveiling the Beneficial Effects of N2 as a CO2 Impurity on Fluid-Rock Reactions during Carbon Sequestration in Carbonate Reservoir Aquifers: Challenging the Notion of Purer Is Always Better.

CO2-enhanced oil recovery (CO2-EOR) is widely used in reservoir development, but its implementation is often limited by scarce pure CO2 sources and high carbon capture costs. Flue gas from steam injection boilers typically contains 10-15% CO2 and 80-85% N2, both of which serve as effective gas displacement agents. Injecting flue gas or CO2/N2 mixtures into reservoirs can reduce carbon emissions, sequester CO2, and enhance recovery. Therefore, this study proposes a concept of enriching rather than capturing flue gas for storage, with a focus on how N2 as an impurity affects the safety of CO2 storage. This study examines interactions between gas mixtures with varying CO2 enrichment rates (with N2 impurities) and minerals. It performs microarea analyses of aged rocks using ultradepth-of-field microscope and atomic force microscopy (AFM), assesses calcite wettability via contact angle tests, and evaluates CO2 storage column height under experimental conditions. Results indicate that with a CO2 enrichment of at least 50%, adding N2 creates additional dissolution pits on calcite surfaces. The calcite matrix exhibits optimal water-wettability at 50-75% CO2 enrichment, facilitating greater CO2 storage column heights. This suggests coinjecting N2 and CO2 can enhance long-term CO2 storage safety and reduce capture costs.

Wood adhesive based on polyvinyl alcohol stabilized polyvinyl acetate, vinyl neodecanoate, vinyl trimethoxy silane, and N-methylol acrylamide copolymer emulsion: synthesis and characterization

To improve a polyvinyl acetate (PVAc) emulsion-based glue’s water resistance, this study aims to offer it a controlled ability for cross-linking. Emulsion polymerization was used to synthesize PVAc-vinyl neodecanoate-vinyl trimethoxy silane-n-methyl acrylamide poly (VAc-VeoVa10-VTMO-NMA) copolymers with polyvinyl alcohol (PVA) stabilization. Using Fourier transform infrared spectroscopy and differential scanning calorimetry (DSC), the copolymerization and glass transition temperatures (Tg) of film were analyzed. To assess the effectiveness of the cross-linked emulsions-based adhesive, the tensile shear strength of wood joints under dry and wet conditions was measured in compliance with the EN 204 and EN 205 standards. The experimental results showed that the copolymer-based poly (VAc-VeoVa10-VTMO-NMA) adhesive significantly increased Tg and film hardness when compared to poly (VAc-VeoVa10-VTMO). Tensile shear strength increased by ∼9% in a dry environment after 24 h of bonding (per EN 204) and by ∼18% in a wet environment with poly (VAc-VeoVa10-VTMO-NMA) adhesive, in comparison to a poly (VAc-VeoVa10-VTMO) adhesive. A contact angle test confirmed that cross-linked poly (VAc-VeoVa10-VTMO-NMA) copolymer adhesives performed somewhat better in wet and heat-resistant conditions than cross-linked poly (VAc-VeoVa10-VTMO) copolymer adhesives. The method proposed provides an easy-to-use route to emulsions with enhanced water resistance and bonding strength by including NMA as a reactive co-monomer.

Wettability of polymer materials with different liquids and effect of contact angle test liquids on calculated surface free energy value

In the first stage of this study, the contact angles (θ) of PC (polycarbonate), PMMA [poly(methyl methacrylate)], and PTFE (polytetrafluoroethylene), which are widely used polymers for various purposes, with different polar [water (W), formamide (F), glycerol (GL), and ethylene glycol (EG)] and nonpolar [diiodomethane (DIO), bromonaphthalene (BRO), and also dodecane (DOD), decane (DEC), octane (OCT), heptane (HEP), and hexane (HEX) from the n-alkane homolog series] liquids were measured and the wettability behavior was investigated in detail. In the second stage, 8 different binary liquid groups were arranged from these liquids whose θs were measured, and the surface free energies (SFE) of the polymers were calculated according to the OWRK-Fowkes method and their standard deviations (SDs) were determined. According to the obtained results, the wetting behavior of nonpolar liquids on polymers differed from that of polar liquids. While the decrease in θ due to surface tension (i.e. the increase in wettability) followed a linear trend for polar liquids, there was a sudden decrease in the range of 50.8–25.4 mN/m for nonpolar liquids and there was no significant change afterward. According to the water θ data, the hydrophobic character of the polymers was ranked as follows from largest to smallest: PTFE (θ: 91.1°) > PC (θ: 81.5°) > PMMA (θ: 77.7°). The average SFE and SDs of the polymers calculated by the OWRK-Fowkes method were as follows: PC 43.8 ± 1.1, PMMA 41.1 ± 5.3, and PTFE 38.9 ± 1.4 mJ/m2. Accordingly, it was determined that the effect of the selected liquid groups on the OWRK-Fowkes SFE values of the polymers was between 2.5% and 12.9%.

A novel approach for flotation separation of talc and molybdenite: Scrap steel-molybdenite galvanic corrosion treatment and its mechanism

Molybdenum is an important strategic resource. Talc-type molybdenite is abundant in reserves, but it is difficult to separate talc and molybdenite efficiently and cleanly because of their similar strong hydrophobicity. In this paper, the effect of galvanic corrosion between scrap steel and molybdenite on flotation behavior of molybdenite was studied under different conditions (different scrap steel materials, slurry water content, galvanic corrosion time and galvanic corrosion ambient temperature).The method for flotation separation of molybdenite and talc by galvanic corrosion of scrap steel-molybdenite was established for the first time. In addition, XPS, SEM, TOF-SIMS, contact Angle test and electrochemical test were used to study the effect of galvanic corrosion of scrap steel-molybdenite on the surface properties of molybdenite and talc. The results show that strong galvanic corrosion between scrap steel and molybdenite can significantly reduce the hydrophobicity of molybdenite, but there is no galvanic corrosion between scrap steel and talc under the same conditions, and scrap steel has no significant effect on the surface hydrophobicity of talc. Therefore, the galvanic corrosion of scrap steel-molybdenite can effectively expand the floatability difference between talc and molybdenite, and strengthen the flotation separation of molybdenite and talc. The flotation test results of artificial mixed ore show that in the case of mineral mixing, the galvanic corrosion of scrap steel-molybdenite still shows a strong inhibition effect on molybdenite flotation, so that 97.04 % of molybdenite in the mixed ore is inhibited into the tailings (molybdenite products). The research results expand the new high-value utilization way of scrap steel in sulfide ore flotation, and help to promote the sustainable development of iron and steel industry and sulfide ores industry. In addition, the research results also have reference significance for the use of scrap steel galvanic corrosion to inhibit other sulfide ores such as pyrite and arsenopyrite.

The Combination of Super-Active Platelet Lysate and Acellular Amniotic Membrane Enhances Endometrial Receptivity, While Simultaneously Facilitating Endometrial Repair in Rats.

To investigate the combined effects of super-active platelet lysate (sPL) and acellular amniotic membrane (AAM) in promoting endometrial repair and enhancing endometrial receptivity in rats. The characteristics of sPL-AAM were examined through scanning electron microscopy, contact angle tester, and release experiments. We aimed to establish a rat model for endometrial injury. We divided sixty-four rats into four groups: the Injury group (Control group), the AAM group, the sPL group, and the sPL-AAM group. Our study compared the endometrial thickness, gland count, and fibrotic area recovery in rats at 6 days and 18 days post-treatment. Immunohistochemistry was utilized to assess the expressions of CD34 and ANG. Additionally, we used ELISA to detect the levels of IL-6 and TNF-α, while Western Blot was employed to compare the expressions of CK19, Integrin β3, and TGF-β1. One month after the treatment, we evaluated and compared the pregnancy recovery among the groups. Compared to the Injury group, the sPL-AAM group demonstrated enhanced endometrial regeneration in rats at both 6 days and 18 days post-treatment, resulting in a favorable pregnancy outcome. This was achieved by promoting angiogenesis, suppressing the inflammatory response, and reducing fibrosis. The observed effects were superior to those of the sPL group alone. While sPL, when administered alone, showed some degree of endometrial restoration at 6 days post-treatment, its efficacy was diminished at 18 days post-treatment. The impact of AAM alone appeared inconspicuous compared to the injury group. This suggests that sPL serves as the primary agent in facilitating endometrial repair, while AAM functions as a carrier to extend the duration of sPL's effectiveness. sPL-AAM can release effective cytokines, repair endometrial damage in rats, enhance endometrial receptivity, and ultimately improve pregnancy outcomes.

Titanium Implant Modified With Zinc-Doped Carbon Dot Layer as an Innovative Coating for the Development of Local Drug Delivery System for Ciprofloxacin.

This study presents a new innovative drug delivery system for ciprofloxacin, which is based on the formation of a zinc-doped carbon dots layer on the surface of a titanium alloy (TiAl4V6). In the study, the effectiveness of the synthesis method of a zinc-doped carbon dots layer was determined. The distribution of the layer of carbon dots on the surface of the titanium alloy was investigated using the FT-IR mapping technique, which confirmed the efficiency of the synthesis. The effective synthesis of carbon dots and the coordination of zinc ions on their surface opens the possibility of sorption of ciprofloxacin, which results in a high application potential of the obtained biomaterial. The introduction of zinc cations on the surface of the carbon dots layer resulted in high sorption results of the active substance (40 μg of drug per 1 cm2 of implant). The release profile of ciprofloxacin from the modified surface of the titanium alloy indicates that this active substance can be released for up to 4 h. The biomaterial obtained in this work is also hydrophilic (about 40°), which was shown by the contact angle tests. This is an important feature and indicates a high application potential of the performed modification. The resulting layer has antibacterial properties. Growth inhibition for microorganisms such as Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Bacillus cereus, and Candida albicans ranged from 74% to 96%. The creation of such a layer on the titanium alloy may reduce the risk of infection during the implantation procedure.

Influence of water-repellent admixtures ( Sitren and Stearate materials) on the microstructure and mechanical performance of conventional Portland cement paste and mortar

The longevity of mortar and concrete structures can be compromised by the absorption of water and other fluids, leading to deterioration and aesthetic issues. To address this, water-repellent admixtures are employed to enhance the service life of mortar and concrete components by improving their mechanical and microstructural characteristics. This study focus on the effects of incorporating Sitren P 750 and various stearate materials (calcium, zinc, aluminum, and barium) as admixtures with ordinary Portland cement at mortar and paste dosages of 0.5%, 1.0%, and 1.5% of the cement content. We found that mortars with water-repellent admixtures exhibited competitive mechanical properties at all curing ages. Additionally, the study confirmed the contribution of these admixtures to the production of hydration products and the structural development of the mortars, as investigated through scanning electron microscopy, thermogravimetric–derivative thermogravimetric, and X-ray diffraction analyses. Despite alterations in several physical properties and hydration kinetics due to the water-repellent compounds and their dosages, all admixtures provided effective water-repellent protection. This was further corroborated by water contact angle tests and the measurement of the capillary water absorption coefficient for all samples. Identifying the optimal mixture ratio for construction technology and effectively incorporating repellence features is a crucial aspect of this research.

Facile fabrication of porous fluorinated polyurethane membranes for organic solvent adsorption based on thiol-ene click reaction within high internal phase emulsions

Porous fluorinated polyurethane membranes show tremendous application potential in organic solvent adsorption. However, the solubilization of fluorinated monomers remain the main obstacle during their polymerization. In this work, we launched a new strategy combining high internal phase emulsion with thiol-ene click chemistry for the facile fabrication of porous fluorinated polyurethane membranes for efficient solvent adsorption. The successful construction of high internal phase emulsions and the effective formation of the designed polymer were confirmed by FTIR, SEM, EDS, XRD, XPS, MIP, and TG/DSC analysis. Contact angle and adsorption capacity tests were also carried out to further illustrate the hydrophobic property and adsorption performance. Results demonstrated that fluorinated polyurethane membranes could be successful synthesized through the in-situ thiol-ene click reaction within high internal phase emulsions. The resulting polymer presented abundant porous structure, excellent thermal stability, good hydrophobic property, and competitive adsorption capacity for several solvents, especially dichloromethane. Furthermore, the structure and properties of the prepared membranes can be effectively altered by regulating the ratio of fluorinated monomer and polyurethane prepolymer. This work presents a facial avenue for designing porous fluorinated polyurethane membranes with a remarkable application potential in solvent adsorption.

Flotation separation of molybdenite from talc using carrageenan as depressant

Due to the strong natural floatability of molybdenite and talc, conventional flotation depressants are difficult to separate these two minerals. As a common depressant, starch has a strong inhibitory effect on both minerals (Castro et al., 2016), while sodium carboxymethyl cellulose has a weak inhibitory effect on both minerals (Chen et al., 2024). Therefore, selecting a proper depressant is the key for achieving the efficient flotation separation. This study investigated the flotation separation of talc and molybdenite using carrageenan as the depressant and sodium butyl xanthate (SBX) as the collector. The micro-flotation test results showed that carrageenan exhibited a strong depressing effect on both talc and molybdenite, and even stronger on molybdenite. However, molybdenite could achieve flotation after adding SBX, while talc was still suppressed. In addition, it was observed that the recovery of molybdenite by adding SBX first was higher than that of adding carrageenan first. A concentrate with a molybdenum grade of 50.64% and recovery of 87.1% was obtained in the artificial ore flotation with the initial grade of 28.52%. The adsorption mechanism of carrageenan on the surfaces of molybdenite and talc was studied using contact angle testing, adsorption capacity testing, zeta potential measurement, Scanning Electron Microscopy-Energy Dispersive Spectrometer (SEM-EDS) analysis, Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) analysis. It was concluded that carrageenan physically adsorbs on both mineral surfaces, whereas SBX adsorbs selectively on the surface of molybdenite and competes with carrageenan for adsorption.

Extraction performance of SiO2@COF before and after carbonization and online SPE-HPLC-DAD methods for tetrabromobisphenol A derivatives and phthalates

The property of organic materials can be regulated by a facile carbonization way. In-situ growth of covalent organic framework on silica (SiO2@COF) was achieved by room temperature synthesis, then SiO2@COF was carbonized to get another material, called SiO2@C-COF. The materials were characterized by SEM, BET, XPS, contact angle test and element analysis. Their extraction mechanisms were evaluated by different model analytes. According to thermodynamic functions, SiO2@COF mainly provided π-stacking effect, while SiO2@C-COF had stronger hydrophobic interaction. Results of dynamic adsorption capacity further verified it, SiO2@COF captured more polycyclic aromatic hydrocarbons (273.62 μg g-1) than SiO2@C-COF (216.89 μg g-1), but it had lower adsorption capacity (44.4 μg g-1) for hydrophobic alkylbenzenes than that on SiO2@C-COF (56.22 μg g-1). So, the carbonization was proved as one effective approach to regulate the surface property of COFs and expand the application fields. Based on these, tetrabrombisphenol A derivatives and phthalates were selected as the analytes. After investigating extraction and desorption conditions, two online solid-phase extraction-liquid chromatographic methods were separately established to detect two types of analytes in water samples. Both methods displayed low detection limits (0.005 μg L-1; 0.01 μg L-1), wide linear ranges (0.0165-15.0 μg L-1; 0.033-15.0 μg L-1), acceptable recoveries (75.55%-127.78%; 71.01%-134.80%), and satisfactory precision (RSDs, 0.1%-7.9%; 0.8%-7.9%), respectively. Compared with other methods, these methods presented some superiorities like better sensitivity, online analysis, and better repeatability. In addition, the sorbents were durable more than 100 runs.

Surface characteristics evolution of 316L stainless steel induced by tension loading

316L stainless steel has been employed as a medical implant material owing to its advantageous biocompatibility and durability. The microstructure and surface characteristics of 316L play a crucial role in implant application. Diverse processing methods were utilized to modify the surface properties of 316L to customize the characteristics of medical devices. Mechanical deformation induces changes in the microstructure and causes changes in surface topography. In this study, we introduced deformation to 316L by applying uniaxial tension at strain values ranging from 2% to 25%. During sample preparation, electrochemical polishing was employed to eliminate the deformed layers generated by mechanical grinding. After the tensile test, a contact angle test was conducted. The surface relief of 316L was examined using three-dimensional (3D) laser scanning microscopy and atomic force microscopy. X-ray diffraction with CuK radiation in the Bragg–Brentano (θ–θ) mode was also employed to identify the phase transformation. It can be concluded that higher strain levels increased surface roughness and the number of slip lines. At higher strain levels, samples exhibited a martensitic transformation, affecting topography changes and the surface free energy. The contact angle measurement results and surface free energy determination showed improved wettability following plastic deformation. Determining the factors that affect surface wettability requires an understanding of the relationship between surface free energy, topography, and surface roughness. Deformation-induced martensite can significantly increase the surface free energy and wettability of 316L stainless steel (SS) by altering strain levels. It is important to consider surface characteristics to understand slip mechanisms at grain boundaries, particularly in cases where surfaces have been electropolished. Nevertheless, the surface also manifested deformation-induced martensitic (DIM) transformation, potentially posing a risk to the passive film and contributing to corrosion, consequently reducing the implant’s lifespan.

Research on the anti-frost performance of hydrophobic TiN-polymer composite coating on aluminum alloy surface

It is well known that the heat exchanger of refrigerator or air conditioner is prone to freezing or condensation, which will affect the cooling effect inside the refrigerator or air conditioner, leading to extra power consumption and bacteria growth. In this study, we developed a multi-step method to prepare hydrophobic surfaces. In the first step, a needle-like structure is made on the surface of the aluminum alloy (AA) by alkali etching. To improve the durability and stability of coatings, different polymers, such as thermoplastic polyurethanes (TPU) or epoxy resin (EP), was mixed with titanium nitride (TiN) particles. Subsequently, the titanium nitride composite coating was applied to the substrate by spraying process or physical brushing technology which could be scaled up in the industry directly. After the final fluorination step, the aluminum substrate was covered with a hydrophobic surface. The results of the contact angle test assumed the hydrophobicity of the EP/TiN/FAS-17 and TPU/TiN/FAS-17 composite coatings. Additionally, compared to the pure TiN coating, the light conversion rate of the composite coatings maintained similar levels while better mechanical strength was achieved. Last but not least, both composite coatings demonstrated excellent ability to hinder icing in frosting and facilitate ice melting in defrosting experiments, further demonstrating their potential for use in anti-icing applications.

Surface Functionalization of CaCO3 Whiskers for Improved Asphalt Binder Compatibility: From Microscale Characterization to Molecular Dynamics

CaCO3 whiskers, as a micron-level inorganic fiber material, can enhance and toughen composite materials. In order to study the technical feasibility of CaCO3 whisker-modified asphalt, two types of silane coupling agent (SCA), KH-550 and KH-570, were applied to treat the surface of CaCO3 whiskers, and the treatment effects of the original and treated whiskers were characterized by scanning electron microscopy (SEM), energy-dispersive spectrometer (EDS) and contact angle test. Meanwhile, models of CaCO3 whiskers, SCA, and asphalt molecules were established by Material Studio (MS, 2020 version) software, and the adhesion mechanism between the CaCO3 whiskers-and-asphalt interface was predicted. The results of microscopic characterization experiments indicate that the surface of the whiskers treated with SCA became rougher. Compared with the original whiskers, the contact angle between the treated whisker surface and water increased from 50° to 92.2° and 103.4°, and the surface of whiskers changed from hydrophilic to hydrophobic. The results of molecular dynamics simulation analysis show that the adhesion performance between the CaCO3 whisker surface and asphalt increased from 100.1 mJ/m2 to 112.5 mJ/m2 and 126.6 mJ/m2 after modification with SCA, and the increase in adhesion energy of KH550 is greater than that of KH570. The above research results indicate that the micro-characterization results were consistent with the molecular dynamics simulation results; that is, after treatment with SCA, the adhesion energy between the whiskers and asphalt was increased to varying degrees. The research method in this article combines micro-characterization with molecular dynamics simulation, which has a certain degree of innovation.