Surface Properties Of Materials Research Articles

Ultrasensitive electrochemical detection of thymol using areca nut fibre-derived carbon sensors for environmental protection

The increasing use of thymol (THY) as a common pesticide in agriculture raises significant concerns regarding its potential environmental and human health risks. Therefore, developing a sensitive detection method for thymol residues is essential for monitoring and ensuring safety standards. This study presents a novel approach for sensitively detecting thymol using activated carbon derived from areca nut (Arecanut catechu L) fibre, an agricultural by-product as the precursor. Cetyltrimethylammonium bromide (CTAB) is added to the test solution to improve the material's surface properties and increase the number of active sites. Electrochemical sensing techniques, specifically cyclic voltammetry (CV) and square wave voltammetry (SWV), are employed to evaluate the performance of Cetyltrimethylammonium bromide mediated activated carbon as a thymol detection sensor. The sensor exhibits outstanding sensitivity with an ultralow limit of detection (DL) of 1.84 × 10⁻⁸ M and a limit of quantification (QL) of 6.14 × 10⁻⁸ M, enabling the quantification of trace amounts of thymol in complex matrices. Furthermore, the sensor demonstrates exceptional reproducibility and long-term stability, making it suitable for real-time applications. Utilizing areca nut fibre as a precursor represents a sustainable and eco-friendly approach. This method offers a promising solution for pesticide detection, contributing to enhanced food safety, environmental protection, and regulatory compliance in the agricultural sector.

Fluorescence Behavior of Cyanine Fluorophore Cy3 Confined in Anodic Porous Alumina: Advanced Surface Analysis

In this study, an advanced analysis of the three-dimensional (3-D) surface microtexture of anodic porous alumina (APA) arrays was conducted to investigate their efficacy in confining cyanine fluorophore Cy3. The microstructural characterization of APA plays a pivotal role in enhancing the understanding of the material's surface properties, especially when applied to biological arrays and fluorescent dye confinement. To achieve this, Atomic Force Microscopy (AFM) was employed to obtain precise 3-D surface microtexture data. These measurements were complemented by stereometric analyses, adhering to ISO 25178-2: 2012 standards, ensuring a robust quantitative and qualitative evaluation of the surface micromorphology. The analysis revealed a clear correlation between surface roughness parameters and micromorphological changes as a function of varied processing conditions. Notably, the increase in certain fabrication parameters led to significant alterations in the superficial texture, with observable changes in the fractal dimension of the surface structure. The APA arrays, fabricated using a specialized anodization technique followed by a tailored annealing procedure, exhibited extraordinarily large pore sizes, ranging from 1 to 2 μm, which are well-suited for accommodating the Cy3 dye molecules. These pore dimensions offer an enhanced capacity for dye confinement, providing a stable environment for the cyanine fluorophore while promoting optimal fluorescence behavior.

Neural Basis of Perceptual Surface Qualities and Materials: Evidence from EEG Decoding

Abstract The human visual system can easily recognize object material categories and estimate surface properties such as glossiness and smoothness. Recent psychophysical and computational studies suggest that the material perception depends on global feature statistics. To elucidate dynamic neural representations underlying surface property and material perception in humans, we measured visual evoked potentials (VEPs) for 191 natural images consisting of 20 categories of materials and then classified material categories and surface properties from the VEPs. As a result, we found that material categories were correctly classified by the VEPs even at latencies of 150 msec or less. The apparent surface properties were also significantly classified within 175 msec (lightness, colorfulness, and smoothness) and after 200 msec (glossiness, hardness, and heaviness). The subsequent reverse-correlation analysis revealed that the VEPs at these latencies are highly correlated with low- and high-level global feature statistics of the surface images, indicating that neural activities about such global features are reflected in the VEPs. Moreover, by using deep generative models (multimodal variational autoencoder models) to reconstruct surface images from the VEPs via style information, we demonstrated that the reconstructed surface images are judged by observers to have very similar material categories and surface properties as the original natural surfaces. These results support the notion that neural representations of statistical features in the early cortical response play a crucial role in the perception and recognition of surface materials in humans.

Surface Speciation in Microwave-Assisted CO Oxidation over Perovskites─The Role of Water and Activation Pretreatment.

As a model for the energy-efficient aftertreatment of exhaust gas components, we studied microwave-assisted (MW) CO oxidation over a (La,Sr)CoO3-δ (LSC) perovskite oxide catalyst under dry and humidified conditions. We found that the use of a MW-based process can offer multiple advantages over traditional thermocatalysis in this scenario, as the nature of the MW-solid interaction offers quick, adaptive, and energy-efficient heating as well as improved yield and lower light-off temperatures. As found by combined CO and water MW-desorption experiments, the presence of technically relevant amounts of water leads to a competition for surface active sites and thus slows the reaction rate without indications for a fundamental change in the mechanism. Remarkably, the performance loss related to the presence of water was less pronounced in the MW-assisted process. Additionally, while we recorded a temperature-dependent degradation of the reaction rate in extended MW-catalysis experiments both in dry and humidified conditions, it quickly recovered after a short reactivation MW-treatment. Our study confirms that surface reaction can be driven by the use of MW-radiation in a similar magnitude that can be achieved by thermal activation at significantly higher temperatures. The nature of the effect of the MW-treatment on the structural and electronic surface properties of the LSC material was investigated by X-ray absorption (XAS) and X-ray photoelectron spectroscopy (XPS). We found evidence of a significant structural, chemical, and electronic reorganization of the oxide surface, possibly consistent with the occurrence of overheated surfaces or "hotspots" during MW-exposure, which may explain the increased catalytic and heating properties of the LSC after the MW-pretreatment. The good catalytic performance, quick response to MW-heating, and long-term stability of the catalyst all indicate the promising potential of a MW-based process for the energy-efficient exhaust aftertreatment using noble-metal-free oxide catalysts.

Strategic design of cobalt-based bimetallic compounds using NH4BF4 as a structure-directing agent for enhancing energy storage ability of battery supercapacitor hybrids

Modifying morphology and composition of metal-organic frameworks (MOFs) can enhance their electrical conductivities and redox states. Structure-directing agents (SDAs) play a key role in shaping surface properties of materials. Ammonium fluoride-based complexes are useful in designing MOF derivatives with excellent energy storage capabilities. Metal species involved also affect redox reactions, which are crucial for energy storage in battery-type electrodes. In this study, cobalt-based bimetallic compounds derived from ZIF-67 are synthesized using 2-methylimidazole and the SDA of NH4BF4. The secondary metal species contain Cu, Al, Zn and Mn, and resulting compositions include hydroxides and hydroxide nitrates. With the optimal 2-methylimidazole to NH4BF4 ratio, the best-performed cobalt-based compound is related to Ni (MB21-CoNi) which demonstrates the highest specific capacitance (CF) of 763.2 F/g at 20 mV/s, attributed to high theoretical capacities and sheets-assembled flower-like structures. A battery-supercapacitor hybrid (BSH) composed of carbon and MB21-CoNi electrodes achieves a maximum energy density of 17.2 Wh/kg at 650 W/kg. A CF retention of 94.9% and a Coulombic efficiency of 88.9% after 10,000 cycles are attained for this BSH. This work provides a blueprint for designing novel active materials with helps of 2-methylimidazole and NH4BF4, and for discussing significant parameters to achieve excellent energy storage ability.

Hybrid Particle Size Template Method for Controllable Synthesis of Nitrogen-Doped Multilevel Porous Carbon as High-Rate Zn-Ion Hybrid Supercapacitor Cathode Materials.

Achieving high rate performance without compromising energy density has always been a critical objective for zinc-ion hybrid supercapacitors (ZHSCs). The pore structure and surface properties of carbon cathode materials play a crucial role. We propose utilizing a hybrid particle size (20 and 40 nm) magnesium oxide templates to regulate the pore structure of nitrogen-doped porous carbon derived from the soybean isolate. The multilevel pore structure enhanced ion transport efficiency while also improving the utilization of micropores. Nitrogen doping and oxygen-containing functional groups enhanced the wettability of carbon materials with aqueous electrolytes and facilitated the chemisorption of Zn2+ on the carbon material surface. The nitrogen-doped multilevel porous carbon material (HT-NMPC-1/1) prepared with a 1 : 1 mass ratio of the two templates exhibited a specific capacity of 146.65 mAh g-1 at 0.2 A g-1. Moreover, the Swagelok cells assembled with HT-NMPC-1/1 and Zn foil achieved a high energy density of 121.5 W h kg-1, high power output of 166 W kg-1, and 93.09 % capacity retention after 8000 cycles at 2 A g-1. Therefore, HT-NMPC-1/1 is a highly promising candidate for ZHSCs cathode materials. Furthermore, the novel pore regulation strategy and straightforward preparation method offer valuable reference points for other porous carbon-based functional materials.

Zn-Modified TiO2 Thin-Films for Real-Time Formaldehyde Sensing at Room Temperature

Abstract This study explores the fabrication and application of zinc-modified titanium dioxide (Zn-TiO2) thin-films for real-time recognition of volatile organic compounds (VOCs), with a particular emphasis on formaldehyde (HCHO) sensing at room temperature. The Zn-TiO2 thin-films were produced using an economical spray-pyrolysis method. Structural, morphological, and optical characterizations confirmed the successful integration of zinc with varied Wt.% (0, 2, 4, and 6) into the TiO2 lattice. The real-time monitoring capabilities of the sensors were assessed against a range of VOCs, highlighting its specificity for formaldehyde detection amidst diverse environmental constituents. The fabricated thin film sensors with zinc dopant were optimized to enhance the sensor's performance. 4 Wt.% Zn-TiO2 demonstrated excellent sensitivity to formaldehyde vapor at ambient conditions, showcasing a rapid and selective response. The underlying sensing mechanism was explored, emphasizing the role of zinc doping in tailoring the material's surface properties and facilitating enhanced adsorption of formaldehyde molecules. The study underscores the potential of Zn-modified TiO2 thin films as a reliable and efficient platform for real-time VOC monitoring, with a specific focus on HCHO sensing at room-temperature. The sensor shows remarkable stability and repeatability, making it a promising candidate for continuous monitoring applications.

Orthogonal Nano‐Engineering (ONE): Modulating Nanotopography and Surface Chemistry of Aluminum Oxide for Superior Antibiofouling and Enhanced Chemical Stability

AbstractDecoupling certain material surface properties can be key to attaining critical property‐activity relationships that underpin their antibiofouling performance. Here, orthogonal nano‐engineering (ONE) is employed to decouple the influences of nanotopography and surface chemistry on surface antibiofouling. Nanotopography and surface chemistry are systematically varied with a two‐step process. Controlled nanotopography is obtained by electrochemical anodization of aluminum, which generated anodic aluminum oxide (AAO) surfaces with cylindrical nanopores (diameters: 15, 25, and 100 nm). To modify surface chemistry while preserving nanotopography, an ultrathin (≈5 nm) yet stable zwitterionic coating of poly(divinylbenzene‐4‐vinylpyridyl sulfobetaine) is deposited on these surfaces using initiated chemical vapor deposition (iCVD). Antibiofouling performance is assessed by quantifying 48‐h biomass formed by gram positive and negative bacteria. The ONE surfaces demonstrated enhanced antibiofouling performance, with small‐pore nanotopography and zwitterionic chemistry each lowered biomass accumulation by tested species, with potential additive effects. The most effective chemistry‐topography combination (ZW‐AAO15) enabled an overall reduction of 91% for Escherichia coli, 76% for Staphylococcus epidermidis, 69% for Listeria monocytogenes, and 67% for Staphylococcus aureus, relative to the uncoated nanosmooth control. Additionally, the composite ZW coating exhibited encouraging anticorrosion properties under both static and turbulent cleaning conditions, vital to antibiofouling applications in healthcare and food industries.

Field‐based estimation of cation exchange capacity using induced polarization methods

AbstractThis study investigates the potential of field‐based induced polarization (IP) methods to provide in‐situ estimates of soil cation exchange capacity (CEC). CEC influences the fate of nutrients and pollutants in the subsurface. However, estimates of CEC require sampling and laboratory analysis, which can be costly, especially at large scales. Induced polarization (IP) methods offer an alternative approach for CEC estimation. The sensitivity of IP measurements to the surface properties of geological materials ought to make them more appropriate than DC resistivity and electromagnetic induction methods, that are sensitive to bulk electrical properties . Such abilities of IP are well demonstrated in the laboratory; however, applications are lacking at field scales. In this work, the ability of field‐based IP to characterize the CEC of floodplain soils is assessed by implementing a methodology that allows for direct comparison between IP and soil parameters. In one field, soil polarization and CEC exhibited the expected positive correlation; but multi‐frequency measurements showed no clear advantage over single‐frequency measurements. In another field, coarser soils (with low CEC) exhibited a high polarization. These coarser soils were characterized by anomalous magnetic susceptibility values, and hence the polarization was attributed to the presence of magnetic minerals. Although better than order‐of‐magnitude estimates of CEC were possible in soils without substantial magnetic minerals, better characterization of porosity, saturation, cementation and saturation exponents, and pore fluid conductivity would improve predictions. However, the measurement of these parameters would require similar efforts as direct CEC measurements. This study contributes to bridging the gap between laboratory‐derived relationships and their applicability in field applications. Overall, this work provides valuable insight for future studies seeking to understand polarization mechanisms in soils at the field scale.

Understanding adhesive sliding nanocontact mechanics in an exponentially graded coating–substrate structure

The objective of this study is to investigate the frictionally adhesive nanocontact characteristics between a sliding rigid cylinder and an exponentially graded coating–substrate structure. Adhesive forces are modeled using the Maugis–Dugdale adhesive theory, while the Steigmann–Ogden surface mechanical theory describes the surface effects of the graded coating. Within the contact region, normal and tangential tractions adhere to the extended Amontons’ friction law. The governing equations and boundary conditions of the nanocontact problem are reformulated into Fredholm integral equations, which are solved numerically using Gauss–Jacobi quadratures and a self-designed iterative algorithm. Validation against existing literature results demonstrates the accuracy and reliability of the proposed solution method and numerical algorithm. Extensive parametric studies are conducted to investigate the effects of various parameters, including surface material properties, coefficient of friction, Tabor’s parameter, inhomogeneity index of the exponentially graded coating, and external loads. Results reveal that sliding friction significantly influences adhesive nanocontact, affecting nanocontact boundaries, contact traction distribution, and adhesive region boundaries. Additionally, surface effects play a crucial role, leading to smaller nanocontact length and maximum pressure but larger adhesive zone. Furthermore, the interplay between sliding friction, surface effects, and adhesion is underscored, emphasizing the importance of considering these factors in the analysis of sliding nanocontact problems involving graded materials. Ultimately, this work provides a comprehensive solution framework for addressing such complex nanocontact scenarios, offering insights valuable to the field of materials science and engineering.

Novel sol-gel derived layered double oxides and layered double oxide/γ-Al2O3 with tunable selectivity as promising adsorbents for L-lactate uptake from the myoblast culture medium

Cultured meat production, a biotechnological solution for global protein demand and sustainability, faces economic challenges due to the high demand for cell culture medium. Contamination with cell metabolites, particularly L-lactate, impedes myoblast proliferation in high-density suspension culture. Eliminating L-lactate is crucial for reusing the medium and overcoming economic barriers in mass myoblast culture. Retaining essential nutrients like D-glucose, amino acids, and vitamins after L-lactate removal is imperative for sustained myoblast growth. This study proposes a sustainable and economically feasible adsorption technique utilizing novel sol-gel derived Mg-Al layered double oxides and Mg-Al layered double oxide/γ-Al2O3 with tunable selectivity as a promising tool for L-lactate uptake from the myoblast medium. In an aqueous solution, L-lactate uptake and selectivity over D-glucose were enhanced with the decrease in total Mg/Al ratio and crystallinity, increase in Al2O3 dispersion in adsorbent, specific surface area, and porosity. The latter was achieved successfully by metal alkoxide sol-gel method employing an organic structure-directing agent, where LDO/amorphous alumina nanohybrid with Mg/Al = 1.23 was successfully prepared in mixed methanol-ethanol solution in a relatively short time. A simple mixture of Mg-Al LDO with Mg/Al = 2 and nano-γ-Al2O3 prepared by a sustainable and economically feasible co-precipitation method was found to have comparable efficiency and selectivity to a costly sol-gel derived material. In myoblast medium, lower total Mg/Al was associated with higher cytocompatibility, pH-stability, and selectivity, while surface properties of materials did not play a significant role. Nano-γ-Al2O3 was identified as the most promising material for selective L-lactate uptake from the myoblast culture medium. Thus, further optimization of the medium treatment process with nano-γ-Al2O3 can realize cost-effective high-density myoblast culture with circular use of the medium – a novel sustainable process in the biotechnology field.

Surface properties of anode materials as an indicator of dendrite growth

Surface properties of anode materials as an indicator of dendrite growth

Emerging Advances around Nanofluidic Transport and Mass Separation under Confinement in Atomically Thin Nanoporous Graphene.

Membrane separation stands as an environmentally friendly, high permeance and selectivity, low energy demand process that deserves scientific investigation and industrialization. To address intensive demand, seeking appropriate membrane materials to surpass trade-off between permeability and selectivity and improve stability is on the schedule. 2Dmaterials offer transformational opportunities and a revolutionary platform for researching membrane separation process. Especially, the atomically thin graphene with controllable porosity and structure, as well as unique properties, is widely considered as a candidate for membrane materials aiming to provide extreme stability, exponentially large selectivity combined with high permeability. Currently, it has shown promising opportunities to develop separation membranes to tackle bottlenecks of traditional membranes, and it has been of great interest for tremendously versatile applications such as separation, energy harvesting, and sensing. In this review, starting from transport mechanisms of separation, the material selection bank is narrowed down to nanoporous graphene. The study presents an enlightening overview of very recent developments in the preparation of atomically thin nanoporous graphene and correlates surface properties of such 2D nanoporous materials to their performance in critical separation applications. Finally, challenges related to modulation and manufacturing as well as potential avenues for performance improvements are also pointed out.

Argon Ion Implantation as a Method of Modifying the Surface Properties of Wood-Plastic Composites.

Wood-plastic composites (WPCs) combine the properties of plastics and lignocellulosic fillers. A particular limitation in their use is usually a hydrophobic, poorly wettable surface. The surface properties of materials can be modified using ion implantation. The research involved using composites based on polyethylene (PE) filled with sawdust or bark (40%, 50%, and 60%). Their surfaces were modified by argon ion implantation in three fluencies (1 × 1015, 1 × 1016, and 1 × 1017 cm-2) at an accelerating voltage of 60 kV. Changes in the wettability, surface energy, and surface colour of the WPCs were analysed. It was shown that argon ion implantation affects the distinct colour change in the WPC surface. The nature of the colour changes depends on the filler used. Implantation also affects the colour balance between the individual variants. Implantation of the WPC surface with argon ions resulted in a decrease in the wetting angle. In most of the variants tested, the most significant effect on the wetting angle changes was the ion fluence of 1 × 1017 cm-2. Implantation of the WPC surface also increased the surface free energy of the composites. The highest surface free energy values were also recorded for the argon ion fluence of 1 × 1017 cm-2.

Rapid surface acetylation of cellulosic materials at room temperature by immersion method

Regulating the surface hydrophobicity of cellulosic materials via surface acetylation can greatly extend their applications. However, most of the existing surface acetylation methods for cellulosic materials are time-consuming and costly. Herein a simple but practical immersion method for the rapid surface acetylation of cellulose materials was reported, which involved soaking cellulosic materials in alkaline aqueous solution followed by immersed them in vinyl acetate. Results showed that simply wetting the surface of cellulosic materials with aqueous alkaline solutions can satisfy their surface acetylation requirement, and the consumption of esterifying agent can be significantly reduced. The immersion method can rapidly improve the surface properties of the cellulosic materials at room temperature within minutes and which is highly attractive to the surface acetylation of cellulose fibers. The moisture regain of the viscose filament obviously decreased after surface acetylation. When the surface acetylated viscose fiber was used as cigarette filter, the total particulate matter in the filtered cigarette smoke significantly reduced from 11.03 mg/cigarette to 6.03 mg/cigarette. The products are promising alternatives to the existing cigarette filters.

Fe oxide modification of yerba mate waste-derived biochar and activated biochar via three methodologies: Effects of material surface properties on the Fe oxides grown and implications for paracetamol and atenolol sorption

This work presents, for the first time, the development of magnetic composites using activated biochar (BC-Act) derived from yerba mate waste. It includes an analysis of the effect of the activation process on the formation of iron oxides using the most applied methodologies, an aspect that has not been studied before. Three methodologies have been considered for Fe oxides grown: coprecipitation (COP), impregnation-pyrolysis (IP), and alkaline oxidation in the presence of nitrates (AOPN). The materials with magnetic response and good enough BET area have been used to sorb Paracetamol (PCT) and Atenolol (ATE) from aqueous solutions. The activation process has resulted in the formation of mesopores, an increase of surface area due to the destruction/release of impurities, the transformation of whewellite to calcite, and changes in magnetic behavior. These changes seem to affect the formation of Fe oxides. The COP and IP methods allow the development of magnetic composites based on BC-Act, BC-Act-COP and BC-Act-IP, with saturation magnetization of 3.1 Am2/kg and 1.5 Am2/kg, respectively, attributed to magnetite/maghemite formation and a minimal distance for manipulation by a magnetic field of 12.1 mm and 7.9 mm, respectively. These distances must be considered when developing efficient removal systems using magnetic composites. PCT was sorbed faster and more efficiently than ATE, associated with its smaller molecular size. This presents a valuable contribution to environmental sustainability and advancements in water purification, highlighting the dual advantage of converting the widely available waste product, predominantly found in South America, into an effective sorbent with magnetic characteristics, capable of removing pharmaceutical contaminants from aqueous solutions. This is done in the circular economy, avoiding the final deposition of yerba mate waste in landfills, increasing their lifespan, and safeguarding other natural and non-renewable resources, such as clays, whose preservation rather than exploitation improves environmental quality and saves energy.

Molybdenum carbide nanosheets with iron doping as electrocatalysts for highly efficient ammonia electrosynthesis

The electrochemical reduction of nitrogen to ammonia represents a greener alternative to the Haber-Bosch process, demanding a shift towards low-cost and high-efficiency electrocatalysts. Recent advances in research have demonstrated the potential of molybdenum carbide-based catalysts to have their unique electronic structure and physicochemical properties. This study introduces ultrathin iron-doped molybdenum carbide nanosheets (Fe-MoC) as a novel catalyst for ammonia electrosynthesis. Demonstrating a remarkable ammonia production rate of 16 µg h−1 mg−1 and a Faradaic efficiency (FE) of approximately 13 % at −0.2 V, our synthesized Fe-MoC nanosheets stand out for their superior catalytic activity and selectivity towards nitrogen activation. The indophenol technique was employed to identify the generation of NH3 in our experiments, followed by UV–vis spectrometry for quantitative analysis. Additionally, various characterization techniques, including XRD, Raman, and XPS, were used to analyze the material structure and surface properties. Through comprehensive characterization and electrochemical studies, we reveal the pivotal role of iron doping in enhancing the electrocatalytic performance for nitrogen reduction reaction (NRR), offering insights into the mechanistic pathways facilitated by Fe-MoC. The future development and perspective of Fe-MoC towards high performance are proposed.

Evaluation of Hardness and Elastic Modulus of Polymer Materials Through Micro-Scratch Method: An Empirical Study

ABSTRACT A number of researchers have focused on scratch methodologies to examine the surface properties of materials. Scratch testing is primarily employed to examine tribological behavior and coating failure. This study attempts to determine the hardness (H) and elastic modulus (E) of polymeric materials via the scratch method. The research performed a progressive loading scratch test on Poly-(ether-ether ketone) (PEEK), Poly(methyl methacrylate) (PMMA), Poly-tetra-fluoro-ethylene (PTFE), polyvinyl chloride (PVC), and High-density polyethylene (HDPE). The least-squares curve fitting model was used to develop two models for assessing the H and E of materials based on indentation and scratch parameters. The H is determined by tangential force, scratch width, residual depth, and E calculated from the recovered depth and additional scratch parameters. Validation of both models indicates a maximum error of around 5%, indicating that the recently established models align well with experimental data. This study presents two robust models for assessing material surface attributes derived from a single scratch test with additional parameters.

Evaluation of optical and mechanical properties of crown materials produced by 3D printing.

The various advantages of crown materials produced using three-dimensional (3D) printers have increased their use in restorative and prosthetic dentistry in recent years. Accordingly, their optical and mechanical properties have become more important. To evaluate the mechanical, surface and optical properties of crown materials produced with 3D printing and computer-aided design (CAD)/computer-aided manufacturing (CAM), which has recently been used frequently in the clinic. The 3-point bending test was used to evaluate the mechanical properties of 2 different crown materials produced with 3D printing (Permanent Crown and VarseoSmile Crown Plus) and a crown material produced using CAD/CAM (Vita Enamic). After the initial color and surface roughness measurements were made, the specimens were immersed in 4 different solutions. The most translucent material was VarseoSmile Crown Plus (p < 0.05). In all specimens, coffee caused the most discoloration (p < 0.05). The effects of the solutions on the roughness were mostly observed in Permanent Crown specimens (p < 0.05). Vita Enamic showed the highest statistically significant values in terms of flexural strength (p < 0.05). The stereolithographic technique among the materials produced by 3D printing can be recommended for use in restorations due to its higher flexural strength.

Flexible SERS chips for rapid on-site detection of tricyclazole pesticide in agricultural products.

A flexible, ultrasensitive, and practical SERS chip is presented based on a paper/f-TiO2/Ag structure. The chip enhances the self-assembly of Ag nanoparticles on a cellulose fiber matrix, facilitated by smart functionalized TiO2 nanomaterials (f-TiO2). This design enables superior detection of the hazardous pesticide tricyclazole (TCZ) on crops using an advanced, simple, and efficient analytical method.Despite its straightforward fabrication process via a solvent immersion method, the intrinsic smart surface properties of the TiO2 bridging material -both hydrophilic and hydrophobic-enable the uniform and dense self-assembly of hydrophilic Ag nanoparticles (NPs) on the cellulose fiber paper substrate. This innovative design provides superior sensing efficiency for TCZ molecules with a detection limit reaching 2.1 × 10-9M, a remarkable improvement compared to Paper/Ag substrates lacking f-TiO2 nanomaterials, which register at 10-5M. This flexible SERS substrate also exhibits very high reliability as indicated by its excellent reproducibility and repeatability with relative standard deviations (RSD) of only 5.93% and 4.73%, respectively. Characterized by flexibility and a water-attractive yet non-soluble surface, the flexible Paper/f-TiO2/Ag chips offer the convenience of direct immersion into the analytical sample, facilitating seamless target molecule collection while circumventing interference signals. Termed the "dip and dry" technique, its advantages in field analysis are indisputable, boasting in situ deployment, simplicity, and high efficiency, while minimizing interference signals to negligible levels. Through the application of this advanced technique, we have successfully detected TCZ in two high-value crops, ST25 rice and dragon fruit, achieving excellent recovery values ranging from 90 to 128%. This underscores its immense potential in ensuring food quality and safety. As a proof of concept, flexible Paper/f-TiO2/Ag SERS chips, with a simple fabrication process, advanced analytical technique, and superior sensing efficiency, bring SERS one step closer to field applications beyond the laboratory.