Surface Characterization Research Articles

Construction of Mo-Doped CuO Incorporated on Carbon Black Modified Disposable Sensor for the Voltammetric Detection of Metol in Environmental Samples

Abstract In this study, a molybdenum-doped copper oxide (Mo–CuO) composite was synthesized via a hydrothermal method and combined with carbon black (CB) to form Mo–CuO@CB. This composite was used to modify a screen-printed carbon electrode (SPCE) for the detection of Metol (MT), an industrial pollutant harmful to both human health and the environment. Structural and surface characterization was performed using high-resolution transmission electron microscopy, field-effect scanning electron microscopy, energy-dispersive spectroscopy, Raman spectroscopy, X-rssy photoelectron spectroscopy, and X-ray diffraction. Electrochemical techniques, including differential pulse voltammetry and cyclic voltammetry, were used to assess the sensor's performance. The Mo–CuO@CB@SPCE sensor exhibited a low detection limit of 2.7 nM, and limit of quantification is 82 nM, a broad linear range (5.0 × 10−9 – 170 mol L-1), and high sensitivity (4.148 μA μM⁻¹ cm⁻²), benefiting from the catalytic activity of Mo–CuO and the large surface area of CB. With recovery rates ranging from 96 % to 100.6% in pond, river, and tap water, the sensor effectively detects MT in environmental samples, ensuring reliable monitoring of this persistent pollutant.

Modeling and characterizing of surface texture produced by scraping process

Abstract Scraping technology is widely used in the guideways manufacturing of high-precision machine tools, yet the scraped surface texture formation mechanism is still not fully understood owing to the complexity and randomness of the scraping process, which limits the study of the tribological properties of scraped bond surfaces. To reveal the formation mechanism of the scraped surface texture, this study adopts the stratified theory to model and characterize scraped surfaces based on the characteristics of the scraping process. The research found tri-Gaussian stratification features in a scraped surface texture and establishes surface stratified model. Tri-Gaussian segmented separation and continuous separation methods are proposed to calculate the component surface parameters for characterizing the scraped surface texture. Segmented and continuous separation methods are respectively applied to analyze and reconstruct simulated tri-Gaussian stratified surfaces and experimental scraped surfaces. The results indicate that the continuous separation method is superior to the segmented separation method and leads to almost the same height and process parameters as the measured surface in the surface reconstruction. This verifies the feasibility and accuracy of the scraped surface texture model and characterization methods. This paper reveals the surface texture formation mechanism from the viewpoint of the scraping process and provides new insights for modeling and characterizing research on scraped surface texture.

Mechanical and surface characterisation of additively manufactured polyetheretherketone for the tribo test

Purpose The additive manufacturing process, such as fused filament fabrication based on material extrusion, fabricates the samples layer-by-layer. The various parameters in the process significantly affect the dimensions, structure and mechanical properties of the fabricated parts. The purpose of this paper is to investigate the surface and mechanical properties that can affect the contact characteristics with other materials during tribological tests. Design/methodology/approach The investigation of 3D-printed Polyetheretherketone (PEEK) includes the measurement of dimensions, microhardness, surface roughness, surface energy and tensile strength to define material characteristics. The crystallinity is measured using an X-ray diffractometer to understand the hardness behaviour. Findings The printing parameters affect its surface roughness, hardness and crystallinity. This change in parameters such as layer thickness and infill density impacts mechanical properties such as hardness and surface roughness, which will influence the contact mechanism with the counter body during any tribological test. The change in a single parameter during the sample fabrication and the change in the surface and mechanical properties are observed. Research limitations/implications The material cost plays an important role in conducting numerous destructive tests, which is a major limitation to conducting parameter optimisation by varying more parameters. The study is limited to the as-fabricated samples rather than finished samples and without any heat treatment. Achieving optimal parameters is integral to the success of additive manufacturing, ensuring the production of components with consistent performance. Practical implications The study aims at the application of 3D-printed PEEK for bush or journal bearings that can be directly used in practice. The mechanical properties discussed in this paper can fill the gap between theory and practice. Social implications The research provides all fundamental properties, including the printing parameters and their effect on the dimensions and surface structure, which are required to understand the material and its use. The results are consistent as at least four samples were tested for tribological behaviour. The conclusion is updated as per suggestions. Originality/value The study outlines the relationship between the change in layer thickness and infill density with changes in surface energy, surface roughness, hardness and tensile strength. The deformation and adhesion during the friction test depend on these properties.

Process optimization and finite element modeling in magnetorheological abrasive finishing of SS-316L with surface characterization

This study explores the potential of Magnetorheological Abrasive Finishing (MRAF) for ultra-precision finishing of SS-316L using a high-performance Nd-Fe-B (N-35 grade) magnetic tool. Key parameters, including the relationship between normal force (Fn) and working gap, magnetic flux distribution, and finishing spot area, were analyzed using ANSYS 2020 R1® Magnetostatic module simulations. Material removal rate (MRR) and surface roughness (Ra) were optimized through response surface methodology (RSM) using a central composite design (CCD) with two primary input factors: SiC abrasive volume fraction (5%, 10%, 15%) and abrasive mesh size (800, 1000, 1200). Statistical analysis via ANOVA revealed a significant influence of process variables, achieving a remarkable surface finish with a minimum Ra of 52 nm in just 60 min, utilizing an MR fluid with 10% SiC abrasives. Microscopic and spectroscopic evaluations confirmed enhanced surface morphology and microstructural refinement. Moreover, bioactivity studies in simulated body fluid highlighted improved hydroxyapatite layer formation on the finished SS-316L samples, underscoring the process’s potential for biomedical applications.

Femtosecond Laser‐Induced Recrystallized Nanotexturing for Identity Document Security With Physical Unclonable Functions

AbstractCounterfeit identity (ID) documents pose a serious threat to personal credit and national security. As a promising candidate, optical physical unclonable functions (PUFs) offer a robust defense mechanism against counterfeits. Despite the innovations in chemically synthesized PUFs, challenges persist, including harmful chemical treatments, low yields, and incompatibility of reaction conditions with the ID document materials. More notably, surface relief nanostructures for PUFs, such as wrinkles, are still at risk of being replicated through scanning lithography or nanoimprint. Here, a femtosecond laser‐induced recrystallized silicon nanotexture is reported as latent PUF nanofingerprint for document anti‐counterfeiting. With femtosecond laser irradiation, nanotextures spontaneously emerge within 100 ms of exposure. By introducing a low‐absorption metal layer, surface plasmon polariton waves are excited on the silicon‐metal multilayer nanofilms with long‐range boosting, ensuring the uniqueness and non‐replicability of the final nanotextures. Furthermore, the femtosecond laser induces a phase transition in the latent nanotexture from amorphous to polycrystalline state, rather than creating replicable relief wrinkles. The random nanotextures are easily identifiable through optical microscopy and Raman imaging, yet they remain undetectable by surface characterization methods such as scanning electron and atomic force microscopies. This property significantly hinders counterfeiting efforts, as it prevents the precise replication of these nanostructures.

Geology of the Golobar and Rumaceo faults, Basque-Cantabrian Pyrenees

ABSTRACT The lateral transition between different styles of deformation is crucial for understanding local-scale structures since it influences orogenic reconstructions at the crustal scale. This is especially important at the westernmost Basque-Cantabrian Pyrenees, where the transition from the thin-skinned Basque-Cantabrian Pyrenees to the thick-skinned Cantabrian Mountains remains a subject of debate. To address this, detailed geological mapping and proper fault characterisation are critical. This research focused on the surface characterisation of the Golobar Fault System, one of the faults located at the transition between the two styles of deformation. The results of this study include not only a detailed geological map of the Golobar Fault System but also its integration with neighbouring seismic sections and well data. This approach enhances the understanding of the deeper portions and lateral thickness variations, thereby providing a more comprehensive understanding of the Golobar area within the regional framework.

Abraded optical fibre-based dynamic range force sensor for tissue palpation

Tactile information acquired through palpation plays a crucial role in relation to surface characterisation and tissue differentiation - an essential clinical requirement during surgery. In the case of Minimally Invasive Surgery, access is restricted, and tactile feedback available to surgeons is therefore reduced. This paper presents a novel stiffness controllable, dynamic force range sensor that can provide remote haptic feedback. The sensor has an abraded optical fibre integrated into a silicone dome. Forces applied to the dome change the curvature of the optical fibres, resulting in light attenuation. By changing the pressure within the dome and thereby adjusting the sensor’s stiffness, we are able to modify the force measurement range. Results from our experimental study demonstrate that increasing the pressure inside the dome increases the force range whilst decreasing force sensitivity. We show that the maximum force measured by our sensor prototype at 20 mm/min was 5.02 N, 6.70 N and 8.83 N for the applied pressures of 0 psi (0 kPa), 0.5 psi (3.45 kPa) and 1 psi (6.9 kPa), respectively. The sensor has also been tested to estimate the stiffness of 13 phantoms of different elastic moduli. Results show the elastic modulus sensing range of the proposed sensor to be from 8.58 to 165.32 kPa.

Effect of Plasma Treatment on Self-Cleaning Features of Acrylic Paint/TiO2-Coated Surfaces for Environmental Pollutant Removal

This study investigates the characterization and performance of self-cleaning TiO2 surfaces synthesized through a one-step preparation process, followed by enhancement via plasma treatment. The process involved coating aluminum foil with an acrylic paint mixture containing nanoparticles of different mass compositions and subsequent plasma treatment using a continuous plasma arc. Scanning electron microscopy revealed the morphology of the treated surfaces, showing an increase in surface area of plasma-treated materials. Energy-dispersive X-ray spectroscopy revealed changes in oxygen and titanium in acrylic paint/TiO2 surfaces as the TiO2 content increased, indicating successful TiO2 incorporation. Raman spectroscopy showed that the bulk structure of self-cleaning acrylic paints is mainly preserved after plasma treatment. Alternating current impedance spectroscopy assessed that plasma treatment reduced agglomeration and increased active sites, especially for the acrylic paint/TiO2 surfaces with 0.5 mg/cm3 TiO2. The contact angle measurements indicated that plasma treatment enhanced the superhydrophobic characteristics and potential self-cleaning abilities of produced acrylic paint/TiO2 surfaces. The efficacy of these plasma-treated surfaces in self-cleaning was evaluated by testing their performance against puddle sediment and automotive oil samples. The study demonstrated that plasma treatment positively impacted the self-cleaning ability of the acrylic paint/TiO2 surfaces, particularly those with 0.5 mg/cm3 TiO2. This enhancement was attributed to the formation of functional groups, improved water repellency, and possible increases in surface area, which collectively contribute to the sustainable self-cleaning properties of the treated surfaces.

Surface characterization of the diamond polishing pads and their performance evaluation in nanofinishing of electroless nickel plating

Surface characterization of the diamond polishing pads and their performance evaluation in nanofinishing of electroless nickel plating

Characterization of Surface and Bottom Longline Artisanal Shark Fisheries in the Northern Gulf of Tehuantepec, Mexico

Characterization of Surface and Bottom Longline Artisanal Shark Fisheries in the Northern Gulf of Tehuantepec, Mexico

Insight into the Corrosion Inhibition Performance of Pistia stratiotes Leaf Extract as a Novel Eco-Friendly Corrosion Inhibitor for Mild Steel in 1 M HCl Solution

In this research, the Pistia stratiotes leaf (PSL) extract was evaluated as a green corrosion inhibitor for the corrosion of mild steel in 1 M HCl using electrochemical measurements and surface characterization. Electrochemical impedance spectroscopy (EIS) spectra showed that the inhibitory activity of the phytochemical compounds enhanced with increasing concentration up to 400 ppm, which was reflected in the increase in the charge transfer resistance and double-layer capacitance. Regarding the effect of immersion time, EIS results indicated that the persistence of the PSL extract was between 4 h and 8 h of exposure time. From polarization curve (PCC) results, the best performance of the corrosion inhibitor was achieved at 400 ppm with an inhibition efficiency of 93.7%. The PSL extract acted as a mixed-type corrosion inhibitor. The adsorption of the phytomolecules on the metal surface obeyed the Langmuir isotherm through a mixed mechanism (physical and chemical interactions) dominated by physisorption. Scanning electron microscopy (SEM) examinations and energy-dispersive X-ray spectroscopy (EDS) elemental analysis of the corroded samples confirmed the anticorrosive protection of the PSL extract. Chemical characterization of the PSL extract by GC-MS revealed the presence of phytol, steroids, and aromatic and long-chain unsaturated fatty acid esters, in order of abundance. Chemical quantum calculations by DFT allowed for determining that the phthalic acid, di(2-propylpentyl) ester compound has the most significant potential to act as the main active component in corrosion inhibition activity.

Formation of bone tissue apatite on starch-based nanofiber-capped nanohydroxyapatite and reduced graphene oxide: a preliminary study.

In the present study, blends of polyvinyl alcohol (PVA), starch (SH), nanohydroxyapatite (Nano-HA), and reduced graphene oxide (r-GO) were used to fabricate an electrospun nano scaffold (ENS), via electrospinning for their potential application in oral and maxillofacial bone soft and hard tissue regeneration. The scaffold was characterized for its physicochemical and mechanical properties. An invitro study was carried out using human osteoblast MG-63 bone cells. Surface characterization, particularly the analysis of calcium content, was performed before and after immersion in the simulated body fluid (SBF). Additionally, the impact of surface treatment on antimicrobial activity was investigated. The results demonstrated that the tensile strength (18.12 ± 0.14MPa), elongation at break (19.23 ± 0.11%), and flexing index (20.15 ± 0.13%) of the ENS were outstanding, indicating promising performance. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assays demonstrated the biocompatible nature of the ENS. The bioactivity test result of ENS showed excellent deposition of bone apatite crystals. The ENS exhibited antimicrobial properties against E. coli (3.41 ± 0.03mm) and S. aureus (3.12 ± 0.08mm). The ENS, possessing the desired properties, has the potential to be tested in large animals for oral and maxillofacial bone and soft tissue regeneration after obtaining the necessary approvals. The developed ENS offers a promising solution for bone tissue regeneration in the oral and maxillofacial region.

In Situ Solid-State Dewetting of Ag-Au-Pd Alloy: From Macro- to Nanoscale.

Metal alloy nanostructures represent a promising platform for next-generation nanophotonic devices, surpassing the limitations of pure metals by offering additional "buttons" for tailoring their optical properties by compositional variations. While alloyed nanoparticles hold great potential, their scalability and underexplored optical behavior still limit their application. Here, we establish a systematic approach to quantifying the unique optical behavior of the AgAuPd ternary system while providing a direct comparison with its pure constituent metals. Computationally, we analyze their electronic structure and uncover the transition of Pd d states to Pd/Ag hybridized s states in the bulk form, explaining the similar optical properties observed between Pd and AgAuPd. Experimentally, we fabricate pure metal and fully alloyed nanoparticles through solid-state dewetting, a scalable method. During the process, we trace the optical transition in the systems from the initial thin film stage to the final nanoparticle stage with in situ ellipsometry. We reveal the interplay between optical properties influenced by chemical interdiffusion and localized surface plasmon resonance arising from morphological changes with ex situ surface characterizations. Additionally, we analytically implement a metallic layer derived from the ternary system in a trilayer device, resulting in a single-time and irreversible color filter, to demonstrate an application encompassing a lithography-free and cost-effective route for nanophotonic devices.

High-energy Mn2V2O7//C asymmetric supercapacitors in aqueous/organic hybrid electrolytes

The demand for advanced energy storage devices, such as high-energy density supercapacitors, has spurred efforts to develop new environmentally friendly and efficient electrode materials and electrolyte solutions for sustainable development. A prominent strategy is the fabrication of high-voltage and energy-density asymmetric supercapacitors (AS). In this study, dimanganese divanadate (Mn2V2O7, MVO) particles were synthesized via a hydrothermal process and used as pseudocapacitive electrodes for AS. The pseudocapacitive MVO electrode offered synergistic advantages of reversible surface or near-surface Faradaic reactions for charge storage. Another approach to address the challenges of limited energy density in supercapacitors was modifying the electrolyte solution to widen the operating voltage window and increase energy density. A hybrid electrolyte solution of 5 M sodium perchlorate (NaClO4) in a mixture of (2:1) volume ratio of acetonitrile (AN) and water (H2O) was introduced to expand the voltage window in the AS. The fabricated AS with MVO as a pseudocapacitive electrode and activated carbon as a double-layer capacitive electrode operated in a voltage window > 2.0 V with the hybrid electrolyte. The AS device exhibited a capacitance of 156.9 F g−1 at 0.1 A g−1 and a high energy density of 87.2 Wh kg−1, surpassing the carbon-based symmetric supercapacitor (58.9 Wh kg−1). Furthermore, the pseudocapacitive supercapacitor showed exceptional long-term stability over 50,000 cycles. Structural and surface characterization of the MVO electrode after CV testing validated that the charge storage mechanism in Mn2V2O7//C was a surface-controlled process. The performance of the AS pouch cell revealed the great promise of the pseudocapacitive electrode in practical applications.

Insights into the degradation mechanism of Fe-40Ni-15Co superalloy exposed to marine atmospheric and high-temperature conditions

This study investigated the corrosion and oxidation mechanism of the Cr-free Fe-40Ni-15Co superalloy with exposure to a tropical marine atmosphere for one year and a subsequent high temperature of 650 °C for 300 h. The degradation behavior of the samples was evaluated based on surface characterization and analysis. In the tropical marine atmospheres, the corrosion process of the Fe-40Ni-15Co superalloy presented an initial localized type after one month of exposure and gradually developed into uniform. The corrosion products were mainly comprised of Fe2O3 and NiO, suppressing the pitting process. During the high-temperature oxidation process, all samples presented super-parabolic oxidation kinetics. Except for the initial active oxidation due to salt deposits, the corrosion products after atmospheric exposure could significantly enhance the oxidation resistance at 650 °C. An explanation for the degradation mechanism of the Fe-40Ni-15Co superalloy was developed based on the synergistic effects of atmospheric corrosion and high-temperature oxidation.

Evaluation of 14-(p-tolyl)-14H-dibenzo[a,j]xanthene as a Highly Efficient Organic Corrosion Inhibitor for Mild Steel in 1 M HCl: Electrochemical, Theoretical, and Surface Characterization

Corrosion of mild steel, particularly in acidic environments such as hydrochloric acid (HCl), remains a critical issue due to its impact on material durability, economic costs, and safety concerns. This study introduces 14-(p-tolyl)-14H-dibenzo[a,j]xanthene (ZM5), a novel and highly effective organic corrosion inhibitor, to mitigate this challenge. Employing advanced electrochemical techniques: electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP), we evaluated ZM5’s performance in a 1M HCl solution, revealing an impressive inhibition efficiency of 94.7%. Surface characterization using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) further confirmed the formation of a robust protective film on the steel surface, shedding light on ZM5’s adsorption mechanisms. Complementing the experimental findings, Density Functional Theory (DFT) simulations provided theoretical insights into the anti-corrosion mechanism of ZM5, aligning well with observed results. These findings underscore ZM5's potential as a highly promising corrosion inhibitor for industrial applications, effectively enhancing the corrosion resistance of mild steel in aggressive environments.

Fluoro-polymer/TiO2 based photocatalysts for hydrogen generation

In view of limited number of studies on photoreforming of synthetic polymers, herein, a series of new glycopolymers are synthesized via RAFT polymerization to obtain diblock copolymers containing fluorinated and non-fluorinated segments in the glucopyranoside. These glycopolymers are used as probes to investigate photocatalytic reactions at different pH values of the modulated TiO2 photocatalyst. Through structural and surface characterizations, photocatalytic activities are investigated. Fluoro-polymers with deacetylated glucose, hydrophilic segment, PGD such as PPFPM-b-PGD and PPFBM-b-PGD could synergistically increase hydrogen generation rate up to 1368 μmol g-1h−1 and 1549 μmol g-1h−1 with quantum yields of 3.34 % and 3.79 % compared to non-fluoro glycopolymers. The presence of both fluorinated and non-fluorinated groups in diblock copolymers enhanced the rate of photocatalytic hydrogen generation compared to the homopolymer. The accelerated photo-reforming is attributed to in-situ fluorine-doped TiO2 along with high affinity and activation of water molecules. These polymers can generate hydrogen via photo-reforming process.

Numerical investigation into the acid flow and reaction behavior in the tight, naturally fractured carbonate reservoir during acid fracturing

Tight naturally fractured carbonate reservoirs require acid fracturing to build the connectivity between the wellbore and natural fractures (NFs), where hydrocarbon is stored. The high leakoff nature of the NF complicates the acid flow and etching pattern, raising the difficulty in acid fracturing design and optimization. To explore the acid flow and reaction behavior in such reservoirs, an acid fracturing model accounting for the NF distribution is developed, which consists of a fracture surface characterization model, a fracture propagation model, and an acid-etching model. Based on the model, the effects of injection parameters and the NF properties on the effectiveness of acid fracturing are investigated. Then, strategies for acid fracturing the tight naturally fractured carbonate reservoirs are proposed. Results show that high pumping rates and retarded acids with low hydrogen ion (H+) diffusion coefficient is conducive to achieving a long acid penetration distance, while a low pumping rate and acids with a high H+ diffusion coefficient facilitates the NF etching. Therefore, a large stimulated area can be achieved by applying a multi-stage alternating injection of the crosslinked acid with a high pumping rate followed by the gelled acid with a low injection rate. NFs impact acid fracturing in two distinct ways: enhancing the non-uniform etching of the fracture surface and reducing the effective acid-etched fracture length through high leakoff. When NF density is high, leakoff control techniques should be employed; and when the NF inclination is high, non-uniform etching techniques should be used to generate acid-etched channels in flow barriers.

Dual layer-coating of PDMS to prevent calcification and bacterial infection for the potential use of urinary tract biomaterials

Polydimethylsiloxane (PDMS) is widely used in medical devices because of its exceptional properties. However, challenges, such as biofouling and bacterial infections, arise from their hydrophobic nature, especially in devices intended for the urinary tract. To address these issues, this study pioneered a surface modification strategy aimed at enriching PDMS with both hydrophilicity and antifouling attributes, making it ideal for urinary tract device applications. We introduced a novel dual-layer coating process, initially grafting a hydrogel-like poly(acrylic acid) (PAA) layer onto PDMS through benzophenone-mediated photoinitiated polymerization to enhance surface hydrophilicity. Subsequently, polyethyleneimine (PEI) was covalently bonded to the PAA layer, ensuring the formation of a stable antifouling surface that prevented bacterial adhesion and calcium deposition. This method guarantees a robust coating that performs consistently across various environmental conditions, including the fluctuating pH levels typical of the urinary tract. Comprehensive surface characterization validated the substantial improvements in hydrophilicity along with significant reductions in bacterial adhesion and calcium deposition. The innovative PAA/PEI dual-layer coating demonstrated marked superiority over conventional uncoated and single-layer-coated PDMS samples, offering a promising solution for enhancing the safety and efficacy of PDMS-based urinary tract devices. The implications of this study extend beyond immediate applications and provide valuable insights into the domains of biomaterials and medical device engineering.

Promising corrosion resistance of mild steel, copper, and aluminum in hydrochloric acid solution using an environmentally friendly corrosion inhibitor

The current study assessed the anticorrosion features of 6-chloro-2-(4-chlorophenyl)imidazo[1,2-a]pyridine-3-carbaldehyde (AIM) in mitigating corrosion of three different metals: Mild Steel (MS), Copper (Cu) and Aluminum (Al) in 1 M HCl solution. The adsorption process of AIM on these metal surfaces, as well as the stability of the adsorbed layer and its relationship with the type of metal were comprehensively investigated. To achieve our objectives, several techniques were used, such as: Potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), SEM surface characterization, and theoretical approaches. Electrochemical impedance spectroscopy investigations revealed high corrosion inhibition rates, reaching 99.01 %, 96.06 %, and 84.8 % for Cu, MS and Al, respectively, at a concentration of 10−3 M of AIM. Potentiodynamic polarisation validated the mixed type nature of inhibitor, a satisfactory correlation was observed between the results obtained by EIS and those obtained by the PDP technique. The adsorption study showed that the process was mainly controlled by chemical adsorption, and metal dissolution was an endothermic process. Additionally, surface analysis by scanning electron microscopy (SEM) confirmed the formation of a protective AIM film on the electrode surface, resulting in a significant reduction in metal dissolution in the presence of aggressive ions. The exploration of the relationship between molecular structure, inhibitory properties of AIM and the studied metals, was conducted through quantum chemical analysis and dynamic molecular simulation.