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Gratings are widely used for coupling into and out of evanescent and propagating electromagnetic modes, which are otherwise not accessible due to their large in-plane wave vector. A precise description of the optical response requires the knowledge of the grating geometry. Here, we present an investigation of the optical properties of dielectric gratings of sub-micron periodicity fabricated on a multilayer structure, which supports Bloch surface waves, by means of spectroscopic ellipsometry. Taking into account non-idealities, such as the finite spectral bandwidth, in the modeling process is shown to be a necessity for an accurate description of the observed spectra. The grating geometry determined from the analysis of ellipsometry data agrees very well with atomic force microscopy scans. Thus, our ellipsometric model is corroborated. [ABSTRACT FROM AUTHOR]

Piezoresponse force microscopy (PFM) is one of the most widespread methods for investigating and visualizing ferroelectric domain structures down to the nanometer length scale. PFM makes use of the direct coupling of the piezoelectric response to the crystal lattice, and hence, it is most often applied to spatially map the three-dimensional (3D) near-surface domain distribution of any polar or ferroic sample. Nonetheless, since most samples investigated by PFM are at least semiconducting or fully insulating, the electric ac field emerging from the conductive scanning force microscopy (SFM) tip penetrates the sample and, hence, may also couple to polar features that are deeply buried into the bulk of the sample under investigation. Thus, in the work presented here, we experimentally and theoretically explore the contrast and depth resolution capabilities of PFM, by analyzing the dependence of several key parameters. These key parameters include the depth of the buried feature, i.e., here a domain wall (DW), as well as PFM-relevant technical parameters such as the tip radius, the PFM drive voltage and frequency, and the signal-to-noise ratio. The theoretical predictions are experimentally verified using x-cut periodically poled lithium niobate single crystals that are specially prepared into wedge-shaped samples, in order to allow the buried feature, here the DW, to be "positioned" at any depth into the bulk. This inspection essentially contributes to the fundamental understanding in PFM contrast analysis and to the reconstruction of 3D domain structures down to a 1 μ m-penetration depth into the sample. [ABSTRACT FROM AUTHOR]

The nonlinear interaction between the tip of a scanning probe microscope (SPM) and a sample is manifested in the emergence of bifurcations and unstable branches in the frequency response of a driven cantilever. While extensively investigated theoretically, exploring the unstable branch in an actual SPM experiment is lacking so far, reflecting the broader challenge in studying mechanical nanojunction oscillators under strongly varying external forces. Here we demonstrate experimental tracking of unstable periodic orbits between two saddle-node bifurcation points in the attractive regime, revealing the full set of stationary oscillatory states. This is achieved by a minimally invasive control scheme based on fast adaptive phase extraction and Fourier discretisation of the tip dynamics. Stabilization of unstable branches of oscillating AFM cantilevers opens avenues for novel experimental modes, potentially enabling ultrasensitive surface detection at considerably large amplitudes with minimal tip-surface interaction, new insights in tip-surface interaction mechanisms, as well as new AFM modes enabling arbitrary setpoint choice while inherently avoiding discontinuities. Unstable dynamic states are of technological importance, however, increasingly smaller systems, down to the nanoscale, are challenging to control due to fast time constants. In this work, the authors present an easy to implement way of accessing unstable branches of an oscillating microcantilever tip in the vicinity of a surface and explore possible applications in the context of Scanning Force Microscopy. [ABSTRACT FROM AUTHOR]

Hospital-acquired infections cause severe patient problems because of the augmented appearance of antibiotic-resistant bacteria, including Pseudomonas aeruginosa. Material surfaces modified with several biophysical parameters can decrease bacterial biofilm formation, which could be an advantageous alternative to treatment with antibiotics. Since stainless steel is an extensively used material for manufacturing medical implants and in healthcare settings, in this study, we used stainless steel (SS 316L and SS 304) to examine the result of the material surface topographies on bacterial biofilm establishment. This work used the electrochemical etching method to modify the stainless steel surface topography as an anode. The electrochemical etching method influenced the nanocones' formation on stainless steel surfaces of both SS316L (Disk-6: 2682 peaks/ μ m 2) and SS304 (Disk-12: 1654 peaks/ μ m 2) estimated by atomic force microscopy and 3D Profilometer reduced the biofilm by 78% and 85%, respectively. Additionally, the higher negative potential on an average of 600 mV measured by Kelvin probe atomic force microscopy reduced the biofilm formation on both SS316L and SS304 surface synergistically compared to the non-electrochemically etched surface. Biofilm growth and nanopotrusions on the stainless-steel surface examined by atomic force microscopy and scanning electron microscopy demonstrated significantly dead bacterial cells (20%) on the electrochemically etched surface than on the non-electrochemically etched surface after 2 h contact time. Our observations exhibit that the nanotextured surface topographies and surface negative potential effectively inhibit bacterial adhesion and biofilm formation. [ABSTRACT FROM AUTHOR]

In this work, we report the properties of molybdenum disulfide (MoS2) thin films deposited on the p-type silicon substrate using RF magnetron sputtering. The structural, vibrational and morphological properties of MoS2 thin films were investigated using the Raman spectroscopy, X-ray diffraction technique (XRD), atomic force microscope (AFM) and scanning electron microscope (SEM). Raman spectroscopy result showed the appearance of broad E12g and A1g Raman peaks even without DC biasing the substrate and becomes sharp and distinct when the substrate is DC biased at 60 V. Post-deposition annealing in sulfur ambient resulted in sharp and distinct Raman E12g and A1g peaks confirming the formation of MoS2 thin film and improved Mo-S bonding on the top surface. X-ray diffraction spectra of the samples validates the formation of MoS2 thin film with the appearance of [002] XRD peak, when the substrates are biased. Improved morphological effects with the reduction in nano-sized defects, advent of continuous film and low surface rms roughness value of 0.872 nm, were observed on samples deposited with substrate biasing and post sulfur annealing. A back-gated thin film transistor was fabricated with Al as source-drain contacts and MoS2 as the semiconducting channel. The fabricated transistor exhibited p-type transfer characteristics with threshold voltage of −3.8 V. As a result of annealing and ambient exposure, MoO3 fragments on the top of thinned MoS2 layer resulted in extraction of hole from MoS2, resulting in the p-type behavior in the fabricated thin film transistor. The combination of XRD analysis, Raman measurements and EDS data of the film confirmed MoO3 inclusions in the MoS2 thin film. [ABSTRACT FROM AUTHOR]

ScN in the rock salt structure is a well-investigated material due to its desirable properties like the high hardness or large thermal conductivity. Recent computations by Adamski et al. [Appl. Phys. Lett. 115, 232103 (2019)] showed that ScN/GaN heterostructures exhibit an outstanding polarization gradient which would be beneficial for polarization induced electron gases. The pseudobinary semiconductor Sc x Al 1 − x N, when maintaining the cubic rock salt structure, could be beneficial for tailoring the polarization gradient using the Sc dependency of material properties. The structural properties of rs-Sc x Al 1 − x N are not fully discovered yet, thus in this work, DC-magnetron sputtered cubic rock salt Sc x Al 1 − x N thin films with 0.55 < x < 1.00 were grown and analyzed on ScN(111)/Si(111). The epitaxial relation of ScN(111) thin films on the Si(111) substrate is determined to be ScN[110] ∥ Si[100]. Furthermore, concentration dependent properties like the lattice parameter of Sc x Al 1 − x N were measured [a(ScN) = 4.50 Å, a(Sc0.55Al0.45N) = 4.30 Å] and the stress σ within the layers was determined. The crystal quality was evaluated using ω -scans, revealing FWHM = 1.14 ° for Sc0.95Al0.05N. The diameters of the columns were determined by atomic force microscopy and scanning electron microscopy and they are range from 34 to 59 nm for 0.55 < x < 1.00. At x = 0.55 , Sc x Al 1 − x N columns in the hexagonal wurtzite as well as cubic rock salt structure were detected. This information about the structural specifications of Sc x Al 1 − x N in the rock salt structure forms the basis for further investigations and experimental confirmation of the electric properties of ScN/GaN heterostructures or even a Sc x Al 1 − x N/GaN based approach for improved structures for high-electron-mobility transistors. [ABSTRACT FROM AUTHOR]

As an effective method to fabricate a large-area cross-sectional sample for lithium-ion battery electrodes, we perform in-plane polishing of LiNi0.8Co0.15Al0.05O2 (NCA) cathode samples and obtain a large cross-sectional area with a diameter of 1.5 mm. The polished cross-sections of NCA cathode particles are sufficiently flat to perform the atomic force microscopy (AFM) measurements on each cathode particle. Following AFM-based Kelvin probe force microscopy and scanning spreading resistance microscopy measurements, an identical in-plane polished NCA sample is assembled into a coin cell for the charge and discharge processes. After 90 charge/discharge cycles, the in-plane-polished sample is successfully disassembled from the coin cell without causing critical damage. In addition, a microcrack structure, which is a typical degradation feature of the cycles of NCA particles, is observed for the identical in-plane polished NCA sample. This indicates that the in-plane polishing method is effective for investigating identical NCA electrode samples before and after the charge/discharge process. Furthermore, the in-plane polishing method can be successfully applied to the large-area polishing of a Si-based anode which is a mixture of Si carbon complexes and graphite particles. This study presents a novel methodology for analyzing the degradation of lithium-ion battery electrode materials. [ABSTRACT FROM AUTHOR]

Dielectric capacitors have garnered significant attention for their promising attributes in advanced pulse power systems of the future, owing to their rapid charge/discharge capabilities, high power density, and remarkable stability. Whereas environmentally friendly lead‐free ceramics are facing serious challenges of low breakdown strength, poor energy storage density, and/or conversion efficiency, which has been an obstacle to developing desirable dielectric capacitors. In this study, high‐quality ultrathin (<20 µm) lead‐free ceramic dielectrics are successfully produced via the tape‐casting method. The local structural characteristics of these ceramics are verified using piezoresponse force microscopy and aberration‐corrected scanning transmission electron microscopy. By introducing Ta5+ ions into Bi0.39Na0.36Sr0.25TiO3 ceramics, the polar clusters tend to decrease together while the maximum applied electric field tends to increase. This phenomenon can be attributed to the decreased grain size and complex polar structure characterized by extremely small polar clusters, enabling the simultaneous achievement of high applied electric field, large polarization, and minimized polarization hysteresis. Notably, the tape‐casted lead‐free ceramics exhibited exceptional comprehensive energy storage performance with a recoverable energy storage density of ≈10.06 J cm−3 and an efficiency of ≈93% under a high electric field of 915 kV cm−1, surpassing the capabilities of most reported lead‐free ceramics. This work offers a viable solution for developing lead‐free ceramic dielectrics with outstanding energy storage capabilities. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Kagome lattices have garnered significant attention due to their promising applications in catalysis, electronics, and magnetics. Although many efforts have been paid to the design and synthesis of Kagome lattices, there is a limited focus on constructing this lattice by multiple interaction forces. In this work, we employ 2,7‐dibromo‐carbazole as precursors to successfully fabricate the two‐dimensional self‐assembly Kagome lattices stabled by multiple interaction forces on Au(111) substrate. Using low‐temperature scanning tunneling microscopy, non‐contact atomic force microscopy and density functional theory calculation, we visualize and identify the four interaction forces within Kagome lattices: Au—N coordination bonds, Au—H hydrogen bonds, Br—Br halogen bonds, and Br—H hydrogen bonds, respectively. This study provides a basic understanding for designing and constructing more complex Kagome lattices. [ABSTRACT FROM AUTHOR]

Thin-walled cylinders are commonly used in the oil and gas pipeline industry. To ensure processing quality, the microstructure and residual stress of AISI 4135 steel samples before and after heat treatment were investigated nondestructively by magnetic hysteresis loop and Barkhausen noise techniques. Surface hardness measurements and microscopic investigations using optical, atomic force and scanning electron microscopies were also conducted to analyze microstructural behavior. The evolution process that occurs in the microstructure and magnetic domains during heat treatment has been characterized in terms of Barkhausen noise activity and coercivity mapping. With an appropriate precalibration procedure, the residual stress variations in the samples under the as-received, quenched and tempered states were monitored quantitatively. The results show that there is a linear correlation between the coercivity and hardness values, and the internal dependence was also validated by the observed microstructural and morphological features of the samples. Finally, the hysteresis behavior dependence of the steel samples on the quenching and tempering process was interpreted from the micromagnetic domain structure. It is shown that the magnetic hysteresis loop and Barkhausen noise techniques could be reliable tools for the quality control of steel components in line production. [ABSTRACT FROM AUTHOR]

Scanning probe microscopy (SPM) is a versatile tool for studying a wide range of materials. It is well suited for investigating living matter, for example, in single-cell neutrophil studies. SPM has been extensively utilized to analyze cell physical properties, providing detailed insights into their structural and functional characteristics at the nanoscale. Its long-standing application in this field highlights its essential role in cell biology and immunology research, significantly contributing to understanding cellular mechanics and interactions. In this review, we discuss the application of SPM techniques, specifically atomic force microscopy (AFM) and scanning ion-conductance microscopy (SICM), to study the fundamental functions of neutrophils. In addition, recent advances in the application of SPM in single-cell immunology are discussed. The application of these techniques allows for obtaining data on the morphology, topography, and mechanical and electrochemical properties of neutrophils with high accuracy. [ABSTRACT FROM AUTHOR]

The growth of NiO epitaxial thin films on (‐201) β‐Ga2O3 by mist chemical vapor deposition (CVD) and the effects of carrier gas selection (N2 and O2) and substrate preannealing treatment on the structural and morphological properties on the grown thin films are explored. X‐ray diffraction analysis reveals successful epitaxial growth with the orientation relationship (111) NiO [0‐11] || (‐201) β‐Ga2O3 [010]. As a carrier gas, O2 results in single‐domain NiO films while N2 leads to the formation of rotational domains. Atomic force microscopy and field‐emission scanning electron microscopy confirm the lateral growth of NiO films, thus highlighting the importance of substrate preannealing at 1200 °C in oxygen atmosphere to obtain flat, high‐quality films. The results demonstrate that the method of mist CVD combined with appropriate substrate preparation and carrier gas selection is effective for the growth of high‐quality NiO/β‐Ga2O3 heterostructures. This achievement opens new possibilities for the development of wide‐bandgap p–n heterojunctions, potentially advancing the field of high‐power oxide‐based electronic devices. [ABSTRACT FROM AUTHOR]

It has been demonstrated that almost all polymer-clay nanocomposites show higher temperature stability than that of pure polymer, which is attributed to the active exfoliated clay nanosheet firmly adsorbed onto the polymer chains, due to polerization and nucleation effect, the clay nanosheets could protect the polymer chains from destroying. To prove such mechanism, the water-soluble polymer nanocomposites (AAA/SLS-MMT) were synthesized by the in-situ polymerization of 2-acrylamide-2-methyl-propane sulfonic acid, acrylamide, 4-acryloylmorpholine, and organically modified montmorillonite. The techniques of nuclear magnetic resonance, atomic force microscopy and scanning electron microscopy etc., clearly characterized the successful synthesized of sample's structure, the exfoliated MMT nanosheet adsorbed polymer chain's scale, and well-dispersed morphology, espectively. The adsorption model, X-ray photoelectron spectroscopy presented the existence of strong adsorption, while molecular simulation calculations first concluded that the strong adsorption energy was -13032.06 kcal/mol. Thermo-gravimetric-analysis proved the temperature of maximum thermal degradation of powder sample (AAA/1.0 wt% SLS-MMT) was over 298 ℃. After ageing at 180 ℃ for 4 h, the apparent viscosity of 5 g/L AAA/1.0 wt% SLS-MMT aqueous solution was 326.7 mPa,s, while that of pure polymer (AAA) was only 8.3 mPa,s. This optimized sample has the smallest FLAPI value at all test temperatures from 180 to 220 ℃ in both fresh and salt water based drilling fluid. All the evidences of high temperature resistance indicate that the strong adsorption can enhance the thickness of hydrated shell and adsorption of clay particles in drilling fluid at high temperature. Such mechanism supplied the better way to design hightemperature resistant fluid loss additives for deep and ultra-deep oil and gas formation engineering. [ABSTRACT FROM AUTHOR]

Herein, a low‐temperature sublimation‐based vapor deposition (SVD) method is developed to synthesize hexagonal crystal plates of cyanuric acid‐melamine (CAM) with outstanding crystallinity. Through meticulous design of the reaction apparatus and careful selection of source materials, substrate‐confined SVD in a tube furnace is explored to grow single crystals of CAM in hexagonal shapes. Additionally, the orientation preference of the (202) facet is revealed, corresponding to the 2D arrangement of the H‐bonded network, of single‐crystalline plates on surfaces using selected area electron diffraction and X‐ray diffraction techniques. By employing atomic force microscopy and scanning electron microscopy for topography characterization, a mechanism of three‐stage step‐growth crystallization is proposed, including nucleation, in‐plane expansion, and out‐of‐plane growth. Furthermore, it is found that the interactions among melamine molecules in CAM synthesized via SVD are more intense compared to those in CAM synthesized via water‐based methods, as evidenced by infrared and photoluminescent spectra studies. Subsequent nanoindentation tests on the (202) facet of CAM single‐crystalline plates reveals a reduced modulus and hardness of 12.8 and 0.82 GPa, respectively. This methodology addresses the longstanding challenge of synthesizing hexagonal CAM single crystals and provides valuable insights for the fabrication of functional organic crystalline materials. [ABSTRACT FROM AUTHOR]

We consider a ring that carries an arbitrary electric charge density in the presence of a scanning force microscopy tip. We propose an algorithm that predicts this charge density from knowledge of the electrostatic ring-tip contribution to the total scanning force microscopy force–distance curves. We first solve the direct electrostatic problem of finding the electrostatic forces by the ring on a scanning force microscopy conducting probe. These forces are in the pN and nN range and, therefore, measurable with current technologies. Finally, we describe a method based on the least squares minimization method to measure the charge on the ring. [ABSTRACT FROM AUTHOR]

The formation and colonization of biofilms inside the oral cavity are still not understood in detail, although biofilms inside the oral cavity can lead to expensive dental diseases like caries, periodontitis, or the detachment of implants. Such biofilms consist, to a large extent, of proteins, carbohydrates, and other macromolecules. Whereas the interaction of proteins with dental materials is widely studied, the literature does not report interactions of polysaccharides. Here, scanning force spectroscopy is used to investigate the adhesion forces of dextran as an abundant polysaccharide on different dental materials. The focus is dental titanium, accompanied by comparisons with dental gold and silicon as reference material. Different pH values and dental materials mimic representative conditions in the oral cavity. The main finding is that dextran adheres very well to dental materials, but with lower adhesion forces than proteins of similar mass, such as bovine serum albumin. As proteins, the adhesion forces increase with the contact time until a plateau is reached and the forces differ with the dental material. However, in contrast to proteins, pH does not play a role because dextran is uncharged over the measured range between pH 4.5 and pH 13. [ABSTRACT FROM AUTHOR]

Plant viruses are perfect candidates for the construction of nanobiotechnological devices. When employed in intricate 2D or 3D architectures, a stable, ordered virus layer, as the foundational plane, is a prerequisite. In former investigations, Coulomb‐force‐assisted self‐assembly is utilized. However, these layers demonstrate instability in further processing in a solution. In this study, an innovative strategy for immobilizing tomato bushy stunt viral (TBSV) nanoparticles through specific binding is reported on. Genetically engineered TBSV nanoparticles with Strep‐Tag II side chains are anchored using surface‐immobilized Strep‐Tactin. Strep‐Tactin, an engineered type of streptavidin with a strong specific interaction with the Strep‐Tag II protein, is immobilized on a silicon wafer through 3‐aminopropyltriethoxyilane and maleimide functionalization. Herein, the investigation involves optimizing the viral concentration and the pH values of the viral solution, facilitating the achievement of an optimal distribution of viral nanoparticles without vacancies during immobilization. The Strep‐Tactin/Strep‐Tag II system significantly improves the coverage of viral particles on the silicon substrate compared to the direct immobilization onto the untreated silicon substrate. The formed layers exhibit remarkable stability, even under sonication. To validate the findings, scanning force microscopy serves as a critical tool for imaging. [ABSTRACT FROM AUTHOR]

Nickel (II) oxide, NiO, is a wide band gap Mott insulator characterized by strong Coulomb repulsion between d-electrons and displays antiferromagnetic order at room temperature. NiO has gained attention in recent years as a very promising candidate for applications in a broad set of areas, including chemistry and metallurgy to spintronics and energy harvesting. Here, we report on the fabrication of polycrystalline NiO using spray-pyrolysis technique, which is a deposition technique able to produce quite uniform films of pure and crystalline materials without the need of high vacuum or inert atmospheres. The composition and structure of the NiO thin films were then studied using x-ray diffraction, and atomic force and scanning electron microscopies (SEM). The phononic and magnonic properties of the NiO thin films were also studied via Raman spectroscopy, and the ultrafast electron dynamics by using optical pump probe spectroscopy. We found that the NiO samples display the same phonon and magnon excitations expected for single crystal NiO at room temperature, and that electron dynamics in our system is like those of previously reported NiO mono- and polycrystalline systems synthesized using different techniques. These results prove that spray-pyrolysis can be used as affordable and large-scale fabrication technique to synthesize strongly correlated materials for a large set of applications. [ABSTRACT FROM AUTHOR]

Simple Summary: Intervertebral disc disease is a very common problem in dogs. The disease causes pain and paralysis and leads to the death of many dogs annually. The disease is intimately associated with disc degeneration and calcification, but the precise mechanisms by which these pathological processes are linked remain a mystery. Most studies to date have focused on imaging changes and histopathology of affected discs, but here we take a novel approach exploring the use of a number of different techniques associated with mineralogy and materials science, including atomic force microscopy and scanning and electron microscopy, and assessing the information they are able to provide. Our results have allowed us to generate some testable hypotheses which could ultimately help to unravel the way in which disc degeneration and disease are linked, and lead to novel methods of prevention and treatment. Intervertebral disc degeneration in dogs occurs in an accelerated way and involves calcification, which is associated with disc herniation or extrusion. The degenerative process is complex and involves the transformation of collagen fibres, loss of proteoglycans and notochord cells and a reduction in water content; however, how these processes are linked to future disc extrusion remains unknown. We have employed techniques including Fourier Transform Infra-red Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Uniaxial Compression Loading and Atomic Force Microscopy (AFM) in an attempt to gain a greater understanding of the degenerative process and its consequences on the physical properties of the disc. FTIR verified by TEM demonstrated that calcium phosphate exists in an amorphous state within the disc and that the formation of crystalline particles of hydroxyapatite occurs prior to disc extrusion. AFM identified crystalline agglomerates consistent with hydroxyapatite as well as individual collagen fibres. SEM enabled the identification of regions rich in calcium, phosphorous and oxygen and allowed the visualization of the topographical landscape of the disc. Compression testing generated stress/strain curves which will facilitate investigation into disc stiffness. Ongoing work is aimed at identifying potential areas of intervention in the degenerative process as well as further characterizing the role of calcification in disc extrusion. [ABSTRACT FROM AUTHOR]

The hierarchic assembly of fibrillar collagen into an extensive and ordered supramolecular protein fibril is critical for extracellular matrix function and tissue mechanics. Despite decades of study, we still know very little about the complex process of fibrillogenesis, particularly at the earliest stages where observation of rapidly forming, nanoscale intermediates challenges the spatial and temporal resolution of most existing microscopy methods. Using video rate scanning atomic force microscopy (VRS-AFM), we can observe details of the first few minutes of collagen fibril formation and growth on a mica surface in solution. A defining feature of fibrillar collagens is a 67-nm periodic banding along the fibril driven by the organized assembly of individual monomers over multiple length scales. VRS-AFM videos show the concurrent growth and maturation of small fibrils from an initial uniform height to structures that display the canonical banding within seconds. Fibrils grow in a primarily unidirectional manner, with frayed ends of the growing tip latching onto adjacent fibrils. We find that, even at extremely early time points, remodeling of growing fibrils proceeds through bird-caging intermediates and propose that these dynamics may provide a pathway to mature hierarchic assembly. VRS-AFM provides a unique glimpse into the early emergence of banding and pathways for remodeling of the supramolecular assembly of collagen during the inception of fibrillogenesis. [ABSTRACT FROM AUTHOR]

The topological and morphological changes of the (001) surface of single‐crystal (La0.3Sr0.7)(Al0.65Ta0.35)O3 during treatment with high‐purity deionized water (DI) have been investigated by atomic force microscopy and scanning transmission electron microscopy (STEM). Etching by DI treatment at room temperature proceeded mainly in anisotropic etching mode, resulting in rectangular etch pits with {001} inner surfaces forming in the surface. The dominant etching mode changed from anisotropic to isotropic with increasing DI‐treatment temperature, and the lowest surface roughness occurred for DI treatment at 50°C for 60 min. Direct observation of the atomic structure of the surface by STEM showed that the etched surface was the B‐site‐terminated (001) surface after anisotropic etching at 50°C for 60 min, in which the B‐site‐terminated atomic layer was found to maintain the B‐site ordered structure existing in the crystal. This is because DI treatment, which does not require high‐temperature heat treatment of the substrate, suppresses element diffusion, sublimation, and formation of point defects on and in the vicinity of the surface. [ABSTRACT FROM AUTHOR]

Candida albicans is one of the agents of invasive candidiasis, a life-threatening disease strongly associated with hospitalization, particularly among patients in intensive care units with central venous catheters. This study aimed to evaluate the synergistic activity of the antifungal peptide ToAP2 combined with fluconazole against C. albicans biofilms grown on various materials. We tested combinations of different concentrations of the peptide ToAP2 with fluconazole on C. albicans biofilms. These biofilms were generated on 96-well plates, intravenous catheters, and infusion tubes in RPMI medium at two maturation stages. Scanning electron microscopy and atomic force microscopy were employed to assess the biofilm structure. We also evaluated the expression of genes previously proven to be involved in C. albicans biofilm formation in planktonic and biofilm cells after treatment with the peptide ToAP2 using qPCR. ToAP2 demonstrated a synergistic effect with fluconazole at concentrations up to 25 µM during both the early and mature stages of biofilm formation in 96-well plates and on medical devices. Combinations of 50, 25, and 12.5 µM of ToAP2 with 52 µM of fluconazole significantly reduced the biofilm viability compared to individual treatments and untreated controls. These results were supported by substantial structural changes in the biofilms observed through both scanning and atomic force microscopy. The gene expression analysis of C. albicans cells treated with 25 µM of ToAP2 revealed a decrease in the expression of genes associated with membrane synthesis, along with an increase in the expression of genes involved in efflux pumps, adhesins, and filamentation. Our results highlight the efficacy of the combined ToAP2 and fluconazole treatment against C. albicans biofilms. This combination not only shows therapeutic potential but also suggests its utility in developing preventive biofilm tools for intravenous catheters. [ABSTRACT FROM AUTHOR]

The objective of this study was the formulation of green, ecofriendly and sustainable nanobiopesticides of Ocimum basilicum with improved pest control efficiency. Preparation of nanobiopesticides was done by nanoprecipitation method. Optimization of formulative parameters was carried out by Response Surface Methodology (RSM). Nanosuspentions were characterized by zeta sizer, atomic force microscopy and scanning electron microscopy. Impregnated filter paper method was used for evaluation of pesticidal activity of nanosuspensions. Optimized nanosuspension showed particle size of 21.65 nm, poly dispersity index 0.1895 and zeta potential -11.3 mV. Nanobiopesticides depicted the significantly (p<0.005) higher morality rate 99.0 ± 4.95 and 95.0 ± 4.75% against Sitophilus oryzae and Tribolium castaneum respectively as compared to crude extract. Stability of nanobiopesticides was examined at 4 °C and 25°C after 3 months of storage. Small change in particle size and PDI value was observed. Particle size was increased from 125.18 nm to 155.6 nm while PDI value was enhanced from 0.1895 to 0.246 after 3 months of storage at 4 °C. Pesticidal efficacy of Ocimum basilicum biopesticides was significantly (p<0.005) increased by the formulation of its nanobiopesticides. [ABSTRACT FROM AUTHOR]

Stable silver nanoparticles were synthesized in solutions containing sodium‐carboxymethylcellulose and polyvinyl alcohol, and their structure, morphology, and physicochemical properties were studied. The morphology and diameter sizes of the nanofibers of carboxymethylcellulose/polyvinyl alcohol containing silver nanoparticles were investigated using atomic force microscopy and scanning electron microscopy. The investigations showed that nanofibers with diameter sizes ranging from 50 to 130 nm were obtained from the carboxymethylcellulose/polyvinyl alcohol/silver nanoparticles solution. The size and form of silver nanoparticles formed within the solution of carboxymethylcellulose/polyvinyl alcohol based on nanofiber were determined by X‐ray diffraction (XRD), UV–visible (UV–VIS) spectroscopy, and dynamic light scattering (DLS) investigations, revealing nanoparticles with diameters ranging from 5 to 26 nm. The nanofiber mat containing silver nanoparticles exhibited significant antimicrobial activity against both Staphylococcus epidermidis and Candida albicans. The nanofiber mat containing stable silver nanoparticles could be utilized as an antimicrobial facemask for air filtration and for the treatment of burn wounds. [ABSTRACT FROM AUTHOR]

A detailed investigation of the structural and vibrational properties of various prestressed silicon nitride membranes patterned with one-dimensional photonic crystal structures is presented. The tensile stress related deformation of the structure in the vicinity of the patterned area is determined by atomic force microscopy scans, while the resonance frequencies and quality factors of the out-of-plane membrane vibrations are measured using optical interferometry. We show that these noninvasive measurements, combined with the results of finite element simulations, provide accurate information on the tensile stress, the elasticity modulus, and the density of these nanostructured thin films. The obtained results are interesting in two ways: first, they show that such highly reflective thin membranes already exploited in various photonics applications possess high-mechanical quality, which also makes them attractive for optomechanics and sensing applications. Second, they represent a nondestructive method to determine key material parameters, which can be applicable to a broad range of fragile nanostructured thin films. [ABSTRACT FROM AUTHOR]

In this work, it was studied the possibility of improving the sEMG signal collected from surface electrodes placed on the skin by depositing metallic nanofilms of three metals (gold, silver, and aluminum) with three different thicknesses (100, 200, and 300) nm on EMG electrodes as an alternative to the used wet gel. To increase the efficiency of electrodes in diagnosis. The properties of metallic nanofilms deposited on the electrodes have been studied by several techniques. X-ray diffraction shows good crystallization, especially for gold samples, and the crystal size increases with increasing sample thickness. Atomic force microscopy scans show that the roughness and size of the particles increase with increasing thickness. The thermal and electrical conductivity also increased, especially with gold plating, compared to the other two metals. The sEMG signal results show acceptable signal enhancement with reduced noise with nanoplating, especially with gold. [ABSTRACT FROM AUTHOR]

The deposition of thin uniform dielectric layers on graphene is important for its successful integration into electronic devices. We report on the atomic layer deposition (ALD) of Al2O3 nanofilms onto graphene grown by chemical vapor deposition onto copper foil. A pretreatment with deionized water (DI H2O) for graphene functionalization was carried out, and, subsequently, trimethylaluminum and DI H2O were used as precursors for the Al2O3 deposition process. The proper temperature regime for this process was adjusted by means of the ALD temperature window for Al2O3 deposition onto a Si substrate. The obtained Al2O3/graphene heterostructures were characterized by Raman and X-ray photoelectron spectroscopy, ellipsometry and atomic force and scanning electron microscopy. Samples of these heterostructures were transferred onto glass substrates by standard methods, with the Al2O3 coating serving as a protective layer during the transfer. Raman monitoring at every stage of the sample preparation and after the transfer enabled us to characterize the influence of the Al2O3 coating on the graphene film. [ABSTRACT FROM AUTHOR]

Recently developed Nickel-Titanium (NiTi) instruments with practical changes have resulted in safer instrumentation. In addition, topographical features on the file surface are a contributing factor to clinical durability. Therefore, this study aimed to investigate both the cyclic fatigue resistance and the roughness change of MTwo and Rotate instruments (VDW, Munich, Germany). Each instrument (n = 6/each group) was scanned with an atomic force microscopy prior to and after instrumentation. In addition, cyclic fatigue testing was conducted for each instrument (n = 11/each group) with stainless-steel blocks, including 45°-60°-90° degrees of curvature milled to the instruments' size. The roughness parameters increased for both systems after instrumentation (p<0.05). Both systems presented an increased roughness following instrumentation (p<0.05). The cyclic fatigue resistance was lowest at 90° for both systems (p<0.05), whereas the Rotate files presented a higher resistance than that of the Mtwo files (p<0.05). Compared to the Mtwo files, Rotate files presented better resistance, while the resistance decreased as the curvature increased. [ABSTRACT FROM AUTHOR]

Scanning force microscopy (SFM) is one of the most widely used techniques in biomaterials research. In addition to imaging the materials of interest, SFM enables the mapping of mechanical properties and biological responses with sub-nanometer resolution and piconewton sensitivity. This review aims to give an overview of using the scanning force microscope (SFM) for investigations on dental materials. In particular, SFM-derived methods such as force–distance curves (scanning force spectroscopy), lateral force spectroscopy, and applications of the FluidFM® will be presented. In addition to the properties of dental materials, this paper reports the development of the pellicle by the interaction of biopolymers such as proteins and polysaccharides, as well as the interaction of bacteria with dental materials. [ABSTRACT FROM AUTHOR]

Epitaxial regrowth of GaN pn junctions is a key technology for realization of a variety of high-performance GaN power electronic devices. However, the regrowth process can introduce impurities and defects that degrade a device's performance. Here, we show that scanning Kelvin probe force microscopy and scanning capacitance microscopy can be used in a cross-sectional geometry to probe dopant distributions and an electronic structure in epitaxially grown GaN pn junctions. These measurements enable profiling of potential and dopant distributions across GaN pn junctions produced by uninterrupted epitaxial growth and by regrowth on an etched surface. Clear differences are observed in comparisons to the electronic structure of these two types of junctions that can be correlated with results of complementary characterization of dopant distributions reported for similarly grown structures. These measurements also suggest the presence of defects in etch-and-regrow pn junction structures that extend nearly 1 μm below the regrown interface. [ABSTRACT FROM AUTHOR]

The fogging of transparent surfaces—condensation of water vapor in the air to a small liquid surface at specific environmental conditions—scatters incident light, creating a blurry vision. Fogging presents a significant challenge in various industries, adversely affecting numerous applications including plastic packaging, agricultural films, and various optical devices. Superhydrophobic or superhydrophilic coatings are the main strategies used to induce antifogging to minimize light scattering. Here, an innovative approach is introduced to mitigate fogging by modifying the surface properties of polymeric films, focusing on corona-treated polyethylene as a model. Coatings were prepared in two successive steps: the addition of radical co-polymerization of methacryloxypropyltriethoxysilane and N-vinylpyrrolidone followed by the step-growth Stöber polymerization of the formed silane monomer. The polymeric dispersion was spread on oxidized films via a Mayer rod and dried. Scanning and force microscopy, FIB, XPS, and UV-vis spectroscopy revealed a thin coating composed of cross-linked siloxane (Si-O-Si) covalently bonded to surface hydroxyls exposing pyrrolidone groups. Contact angle measurements, hot-fog examination, and durability tests indicated a durable antifogging activity. [ABSTRACT FROM AUTHOR]

This study outlines the fabrication process of an electrochemical platform utilizing glassy carbon electrode (GCE) modified with multi-walled carbon nanotubes (MWCNTs) and palladium nanoparticles (PdNPs). The MWCNTs were applied on the GCE surface using the drop-casting method and PdNPs were produced electrochemically by a potentiostatic method employing various programmed charges from an ammonium tetrachloropalladate(II) solution. The resulting GCEs modified with MWCNTs and PdNPs underwent comprehensive characterization for topographical and morphological attributes, utilizing atomic force microscopy and scanning electron microscopy along with energy-dispersive X-ray spectrometry. Electrochemical assessment of the GCE/MWCNTs/PdNPs involved cyclic voltammetry (CV) and electrochemical impedance spectroscopy conducted in perchloric acid solution. The findings revealed even dispersion of PdNPs, and depending on the electrodeposition parameters, PdNPs were produced within four size ranges, i.e., 10–30 nm, 20–40 nm, 50–60 nm, and 70–90 nm. Additionally, the electrocatalytic activity toward formaldehyde oxidation was assessed through CV. It was observed that an increase in the size of the PdNPs corresponded to enhanced catalytic activity in the formaldehyde oxidation reaction on the GCE/MWCNTs/PdNPs. Furthermore, satisfactory long-term stability over a period of 42 days was noticed for the GCE/MWCNTs/PDNPs(100) material which demonstrated the best electrocatalytic properties in the electrooxidation reaction of formaldehyde. [ABSTRACT FROM AUTHOR]

Atomic force microscopy (AFM) was successfully used to study spin‐coated, amine‐cured epoxy film microstructure and morphology. The air‐epoxy and epoxy‐substrate interfaces were examined using tapping‐mode height and phase imaging AFM. The impact of relative humidity on the morphology and microstructure of the surfaces was determined. AFM was able to elucidate the changes on the surface as relative humidity during processing increased. It was observed that large nodular formations formed on the epoxy surface expose to the air but not epoxy surface formed on the substrate in addition to varying regions of more or less compliant structures, which was attributed to carbamate formation caused by the amine curing agent reaction with atmospheric CO2. Scanning electron microscopy (SEM) was used to further elucidate interface and interphase morphology of spin‐coated epoxies. Experimentation also demonstrated that post‐curing above the glass transition did not change the morphology structure, suggesting surface structures are "locked‐in." SEM was used to further elucidate how the interface and interphase change with changing environmental conditions at both the air‐epoxy and epoxy‐substrate interface/interphases, including the impact of atmospheric CO2 on Marangoni cell formation. [ABSTRACT FROM AUTHOR]

Among the methods commonly used to obtain polymer‐metal hybrids, sputtering has stood out for its ability to deposit thin films at room temperature. Another highlight is that it does not produce toxic gases or residues to the environment, making it an eco‐friendly solution. This work aimed to produce and characterize stainless steel (SS) films on acrylonitrile‐butadiene‐styrene (ABS) polymer using a magnetron sputtering with a direct current source. The ABS‐SS surface and interface, the ABS thermal behavior, and the film‐substrate adhesion quality were analyzed. The characterization techniques were atomic force microscopy and scanning electron microscopy to reveal the surface, x‐ray fluorescence spectroscopy to determine the chemical composition, and transmission electron microscopy to determine the phases on the ABS‐SS interface. The samples' thermal behavior was analyzed through thermogravimetry and differential scanning calorimetry. Method B from the ASTM D3359 standard qualitatively evaluated the film‐substrate adhesion. The characterizations showed that the ABS did not degrade significantly during SS deposition and that the sample had acceptable film‐substrate adhesion quality, making the technique and deposition parameters suitable for the obtention of this hybrid material. [ABSTRACT FROM AUTHOR]

[Display omitted] Contact angle can be a key parameter in chemical engineering. However, the development and the optimization of numerous processes using supercritical CO 2 , considered as environmentally friendly, require new measurements under dense CO 2 atmosphere. Besides, the influence of the roughness or the wetting regime on the contact angle is known at ambient conditions but remains to be discussed for systems under high pressure. Contact angle measurements of ethanol, water, and their mixtures, with ethanol mass fractions ranging from 0.25 to 0.75, on two stainless steels in saturated CO 2 at pressures ranging from 0.1 MPa to 15.1 MPa, and at 313 K and 333 K were carried out in a set-up improving mass transfer between the studied liquid and the continuous fluid phase. Stainless steel surfaces have been characterized by atomic force and scanning electron microscopies allowing the application of the Wenzel equation. Ethanol wetted totally both stainless steels while contact angles of all other liquids were increased by the rise of pressure, with contact angles up to 128° for water at 15.1 MPa. Trapped bubbles were observed at the solid/liquid interface and the bubble formation is discussed. Furthermore, the potential influence of bubble presence on the wetting regime is prospected through the question: could the pressure rise modify the wetting regime? [ABSTRACT FROM AUTHOR]

Techniques for effectively harnessing lead (Pb) deposits for optimum utilization have attracted a lot of research interest. Results obtained from investigating the elemental composition, vibrational modes, and structural properties of a fired Pb composite deposit, which is purified using an electric kiln furnace and further annealed in palladium‐diffused hydrogen ambient, are reported in the present study. Both atomic force microscopy and scanning electron microscopy analysis on the deposit indicate that the Pb composite is composed of crystal‐like morphology. The vibrational modes obtained from the material are identical to the Raman spectrum reported for PbSO4. Also, data acquired from the energy‐dispersive X‐ray analysis of the annealed Pb composite material confirm the presence of zinc, carbon, silicon, sulfur, and oxygen in the material. At the same time, Pb appears to be the primary constituent with reference to its weight percentage composition compared to other elements. The findings from the present study may be vital for providing an improved understanding of the electronic and structural properties of the annealed Pb composite deposit while promoting the development of a feasible approach for the recovery and recycling of Pb for future related applications. [ABSTRACT FROM AUTHOR]

The growth of InAs quantum dots (QDs) by droplet epitaxy (DE) in metal–organic vapor phase epitaxy is demonstrated for the first time on an InGaAsP layer lattice matched to InP(100). The nucleation of indium droplets on InGaAsP shows a strong dependence on the deposition temperature, with an unexpectedly low density, pointing to a strongly increased surface diffusion compared to bare InP or InGaAs surfaces previously reported. Droplets and surface morphology are characterized via atomic force microscopy and scanning electron microscopy. Droplet crystallization into InAs QDs is explored, where the crystallization process follows a modified DE growth which resembles the one on InGaAs but strongly differs from bare InP. Also, no formation of quantum dashes (QDashes) is observed, as the DE growth technique used here allows for a better control of QD nucleation, decoupled from the layer/epilayer mismatch, favoring the formation of QDs over QDashes. Optical characterizations suggest a more efficient carrier capture into the QDs if these are grown on InGaAsP compared to InGaAs. Finally, bright single‐dot emission at low‐temperature is detected from QDs ranging from 1300 to 1600 nm, covering the technologically relevant telecom C‐band. [ABSTRACT FROM AUTHOR]

Vanadium redox flow battery (VRFB) electrodes face challenges related to their long‐term operation. We investigated different electrode treatments mimicking the aging processes during operation, including thermal activation, aging, soaking, and storing. Several characterization techniques were used to deepen the understanding of the treatment of carbon felts. Synchrotron X‐ray imaging, electrochemical impedance spectroscopy (EIS) with the distribution of relaxation times analysis, and dynamic vapor sorption (DVS) revealed differences between the wettability of felts. The bulk saturation after electrolyte injection into the carbon felts significantly differed from 8 % to 96 %. DVS revealed differences in the sorption/desorption behavior of carbon felt ranging from a slight change of 0.8 wt % to over 100 wt %. Additionally, the interactions between the water vapor and the sample change from type V to type H2. After treatment, morphology changes were observed by atomic force microscopy and scanning electron microscopy. Cyclic voltammetry and EIS were used to probe the electrochemical performance, revealing different catalytic activities and transport‐related impedances for the treated samples. These investigations are crucial for understanding the effects of treatments on the performance and optimizing materials for long‐term operation. [ABSTRACT FROM AUTHOR]

This study reports the synthesis of a flexible light‐emitting polymer film by casting the solution formed by blending poly[2‐methoxy‐5‐((2‐ethylhexyl)oxy)‐1,4‐phenylenevinylene] (MEH‐PPV) with poly(styrene‐co‐butadiene‐co‐styrene) (SBS). Scanning force microscopy (SFM) and differential scanning calorimetry (DSC) confirm that MEH‐PPV molecules are selectively positioned in the polystyrene (PS) domain of the fabricated film. As MEH‐PPV molecules are dissolved in the PS phase without aggregation, the photoluminescence (PL) spectrum of the MEH‐PPV/SBS film exhibits a nanometer‐scale bicontinuous luminescent domain with low aggregation quenching. Furthermore, the MEH‐PPV/SBS film exhibits typical elastomeric characteristics (with linear elasticity, a plateau, and densification regions in its stress–strain curves), and its tensile properties are comparable to those of neat SBS films. As MEH‐PPV molecules are almost absent in the polybutadiene (PB) phase (which influences the bulk‐film elastic properties), the concentration of MEH‐PPV shows very little effect on the elastic properties of the composite film. [ABSTRACT FROM AUTHOR]

Van der Waals heterostructures are an excellent platform for studying intriguing interface phenomena, such as moiré and proximity effects. Many of these phenomena occurring in such heterostructures' interfaces and surfaces have so far been hampered because of their high sensitivity to disorder and interface contamination. Here, it reports a dry polymer‐based assembly technique to fabricate arbitrary designer van der Waals heterostructures with atomically clean surfaces. The key features of the suspended dry pick‐up and flip‐over assembly technique are: 1) the heterostructure surface never comes into contact with polymers, 2) the assemble is entirely solvent‐free, 3) it is entirely performed in a glovebox, and 4) it only requires temperatures below 130 °C. By performing ambient atomic force microscopy and atomically‐resolved scanning tunneling microscopy on example heterostructures, it demonstrates the fabrication of air‐sensitive heterostructures with ultra‐clean interfaces and surfaces. It envisions that, due to the avoidance of polymer melting, this technique is potentially compatible with heterostructure assembly under ultra‐high vacuum conditions, which promises ultimate heterostructure quality. [ABSTRACT FROM AUTHOR]

In the twenty-first century, scanning probe microscopy characterization techniques have seen significant progress and are capable of probing complex structures and devices for a variety of near-surface features and phenomena with nanometer scale resolution. With modest customization, we can deploy these techniques for industrial metrology purposes in a simultaneous and multimethod system capable of shedding light on device function and failure modes, as well as determining the most efficient methods for data collection. To demonstrate this concept with a current, complex industrial device under development, several scanning probe microscopy techniques advantageous to the progress of heat-assisted magnetic recording heads were selected. This work describes simultaneous and multimethod approaches for performing heat-assisted magnetic recording head characterization using atomic force microscopy with scattering scanning near-field optical microscopy simultaneously performed with magnetic force microscopy or photo-induced force microscopy that could be extended to applications of other complex nanoscale devices. We demonstrate that the optical and magnetic fields are overlapping for fabricated heads, which is necessary for performing heat-assisted magnetic recording. We also observed that the multimethod atomic force microscopy methods show strong agreement between the measured optical and magnetic fields and the locale of their associated parts on the head. [ABSTRACT FROM AUTHOR]

Combining scanning force microscopy characterization and theoretical modeling, in this work, we performed an in-depth study on the electrical/mechanical switching and electroresistance effect in a BaTiO3 thin film. Correlations of the tip load (bias/force and loading time), the switched polarization magnitude, the surface potential, and the tunnel electroresistance are revealed for both electrical and mechanical switching. It is found that electrical switching (with a maximum bias of 4 V) leads to larger saturated switched polarization and sharper switched domain than mechanical switching (with a maximum force of 6600 nN). Meanwhile, mechanical switching exhibits generally smaller surface potential of the switched domain and a more significant tunnel electroresistance effect. However, the load time-dependence of performance is also more serious for mechanical switching. The different characteristics between electrical and mechanical switching are attributed to the charge injection and the switched domain size, which are believed to further affect the surface potential and the tunnel electroresistance of the thin film. At the end, an optimized hybrid switching strategy, which combines tip force and bias, is proposed and shown to be able to achieve complete polarization reversion, low charge injection, high switch speed, and strong tunnel electroresistance effect. [ABSTRACT FROM AUTHOR]

It is known that high-index perovskite ferroelectric thin films exhibit giant permittivity, piezoelectric response, and a particular switching behavior. However, the fine domain configuration in high-index ferroelectric films is not yet clarified, which triggers difficulties to further modulate their electric properties. In this work, we focus on the tetragonal PbTiO3 thin films with thicknesses of 20, 40, 55, and 70 nm deposited on a [101]-oriented KTaO3 substrate. By using piezoresponse force microscopy and state-of-the-art scanning transmission electron microscopy, the stripe a/c domains with alternately wide c and narrow a domains are observed in all these PbTiO3 films. The periodic stripe a/c domains with {101} domain walls extend along the in-plane [ 11 1 ¯ ] or [ 1 1 ¯ 1 ¯ ] direction, which almost completely relaxes the misfit strain between the PbTiO3 films and the KTaO3 substrate. The domain width decreases as the film thickness is reduced following the square root dependence. This results in an increase of ferroelastic a/c domain walls and promotes the enhancement of the piezoresponse amplitude for the thinner PbTiO3 films. In addition, the piezoresponse amplitude of a 20 nm PbTiO3 film is comparable to that of a 40 nm PbTiO3 film, which indicates that the piezoelectric response of ferroelectric films may saturate at a certain film thickness and scarcely increase even after the film thickness reduces further. These results clarify the domain configurations of [101]-oriented PbTiO3 thin films and provide useful information for understanding the relationship between microstructures and piezoelectric properties in ferroelectric films. [ABSTRACT FROM AUTHOR]

Mixed transition metal oxide films are emerging as efficient and inexpensive potential alternatives to multilayer cermet spectrally selective coatings. However, to replace the current standards involving a complex metal–dielectric structure, oxides must be optimized in terms of their electronic structure and mainly their film morphology. In the present work, a simple ultrasonic nebulized spray pyrolysis technique is used to deposit CuCo2O4 films for solar absorber coatings. Their photothermal efficiencies are studied for solar thermal energy harvesting for different film thicknesses obtained by varying the deposition time. The film surface attributes are studied using atomic force microscopy and scanning electron microscopy. The films deposited for 5 and 10 min show relatively high visible absorptance (∼0.79) and relatively low thermal emittance (∼0.1) and thus are promising candidates for spectrally selective coatings. Meanwhile, increasing the deposition time (>10 min) increases the thickness, thereby increasing the solar absorptance. However, this results in an uncontrolled increase in the surface roughness, which affects the spectral selectivity adversely, leading to the films having higher thermal emittance of between 0.1 and ∼0.25. Analysis of the specular reflection contribution shows that this deterioration is governed predominantly by interference effects due to surface attributes. This study is important for the technological applications of spectrally selective coatings and makes a significant quantitative contribution to emphasize the importance of surface morphology in optics. [ABSTRACT FROM AUTHOR]

BACKGROUND: As a coating material, chitosan can effectively improve biological properties of medical metal surfaces due to its excellent film-forming and metal binding abilities. However, the biological activity and osteoinductive ability of chitosan are insufficient. Graphene oxide can improve the mechanical properties and biocompatibility of various polymer materials, as well as promote osteogenic differentiation. The combination of chitosan and graphene oxide may have better biological properties and osteogenic activity. OBJECTIVE: To construct the graphene oxide-modified chitosan composite coating material, analyze the surface morphology, chemical composition, and physical properties of the coating material, as well as the effects of the coating materials on proliferation, adhesion, and osteogenic differentiation of osteoblasts. METHODS: The titanium surface was treated with 3-aminopropyltriethoxysilane to form silane groups on the surface, and then glutaraldehyde was used to cross-link chitosan with silane groups to prepare simple chitosan coating and graphene oxide/chitosan composite coating, respectively. The surface morphology, chemical structure and hydrophilic properties of the coatings were characterized by atomic force microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, and contact angle measurement system. Rat osteoblasts were seeded on the surface of the two materials, and the proliferation, spreading, and osteogenic differentiation of rat osteoblasts were analyzed by CCK-8 assay, scanning electron microscopy, and reverse transcription-polymerase chain reaction analysis. RESULTS AND CONCLUSION: (1) The thickness of the graphene oxide sheets was about 2 nm as measured by atomic force microscopy; the scanning electron microscopy showed that the surfaces of both coatings were smooth and dense, in which the chitosan molecules were closely arranged and the graphene oxide was uniformly distributed in the chitosan, while wrinkles appeared on the surface of chitosan due to the addition of grapheme. The contact angle of the graphene oxide-chitosan composite coating was significantly smaller than the chitosan coating alone (P < 0.05). (2) CCK-8 assay showed that the graphene oxide-chitosan composite coating better promoted the proliferation of osteoblasts compared with the chitosan coating alone. (3) The scanning electron microscopy showed that better spreading was found in osteoblasts on the surface of the graphene oxide-chitosan composite coating compared with the chitosan coating alone. (4) Reverse transcription-polymerase chain reaction analysis showed that the mRNA expression of alkaline phosphatase and Runx2 was significantly increased in the graphene oxide/chitosan composite coating group compared with in the chitosan coating alone group (P < 0.05). (5) These findings suggest that graphene oxide/chitosan composite coating had good biocompatibility, physicochemical, and osteoinductive properties. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) Ruddlesden–Popper (RP) perovskites hold great potential for novel optoelectronic applications. However, their unconventional optoelectronic properties are often compromised by a vulnerability to light irradiation, which leads to the formation of metallic Pb (Pb0) defects. This study investigates the passivation mechanism of these Pb0 defects in phenylethylammonium lead iodide (PEA2PbI4) using a strong molecular acceptor, 2,2′‐(perfluoronaphthalene‐2, 6‐diylidene) dimalononitrile (F6-TCNNQ). In situ x-ray photoelectron spectroscopy results demonstrate that F6-TCNNQ effectively removes the light-induced Pb0 states, leading to the recovery of photoluminescence intensity in photodegraded PEA2PbI4 samples and significantly improving the photostability of pristine PEA2PbI4. F6-TCNNQ protects the terrace edge of PEA2PbI4, which is the site of initial degradation, as evidenced by atomic force microscopy and scanning electron microscopy analyses. In situ ultraviolet photoelectron spectroscopy measurements confirm substantial electron transfer from Pb0 to F6-TCNNQ, causing the oxidation of Pb0 to Pb2+. Furthermore, the staggered energy level alignment prevents electron transfer from the valence band maximum of PEA2PbI4 to the lowest unoccupied molecular orbital of F6-TCNNQ, thereby preserving the pristine electronic structure of PEA2PbI4. These findings provide new insights into defect passivation in 2D RP perovskites and offer a design strategy for highly stable optoelectronic devices. [ABSTRACT FROM AUTHOR]

Nonspecific adsorption has always been a critical challenge for sensor detection; thus, an efficient and facile approach for fabricating antifouling sensors is highly desirable. Here, we developed an antifouling coating on sensor surfaces, conveniently made with a simple drip of phase-transited BSA (PTB) followed by a modification with a peanut allergen antibody, which unexpectedly provides synergistic antifouling properties in sensors. Atomic force microscopy and scanning electron microscopy were used to evaluate the surface evenness. Optimizations in terms of PTB modification time and concentrations were performed using surface plasmon resonance by measuring protein resistance capabilities. Compared to bare Au surfaces, the PTB-modified surfaces exhibited low adsorption against BSA (<10 ng/cm2) and good resistance against lysozyme (Lyz). After immobilizing antibodies, the antifouling performance of the sensor coatings had an obvious enhancement, with almost no BSA adsorption and low lysozyme adsorption. The target recognition was also analyzed to verify the good sensing performance of the antifouling sensor. This understanding of antibody synergy provides suggestions for the development of antifouling sensors. [ABSTRACT FROM AUTHOR]

The main objective of this research is to investigate how curcumin liposomal nanocarriers influence the drug release behaviour of PVA/PEG hydrogels in relation to physico-mechanical properties. For this purpose, optimal nanoliposomes from drug loading and release viewpoints, prepared by the thin-film hydration method, were incorporated into the hydrogel composition. Hydrogel samples were physically crosslinked using the freeze–thaw procedure. According to the dynamic laser scattering, atomic force microscopy and field-emission scanning electron microscopy observations, negative nanoliposomes with negative surface charges showed a spherical morphology with an average particle size of about 100 nm and narrow size distribution. The X-ray diffraction results revealed that adding nanoliposomes to the hydrogel increases the degree of PVA chains crystallinity, enhances tensile modulus and tensile strength of the hydrogel, while decreasing swelling and dehydration rates. SEM micrographs observation displayed that the porosity in the hydrogel structure in the presence of nanoliposomes increases. Nevertheless, in agreement with physical properties, drug release from nanoliposome-in-hydrogel is slower and more controlled as compared to that from free curcumin hydrogel, especially in the early stages. The MTT assay results indicated that although all hydrogel samples are non-toxic, human foreskin fibroblast cell proliferation on hydrogel in the presence of curcumin-loaded nanoliposomes has improved somewhat. [ABSTRACT FROM AUTHOR]

Surface modifications of dental implants play a crucial role for material stability, durability, and patient contentment; hence optimization of the commonly used techniques can have significant impact. Surface properties affect the osseointegration of implants; however, the surface for the optimal osseointegration is still being researched. Herein, the surface roughness and topography of dental implant screws after polishing, sandblasting, and laser treatment via tapping‐mode atomic force microscopy are investigated. The measurements are performed at the implants' shank, crest, and root sites and evaluated for surface roughness, kurtosis, and skew values. Laser‐treated and sandblasted samples have a significantly higher roughness compared to the machined sample. The roughness at the root of the samples is higher in case of the laser‐treated and machined samples, while lower for the sandblasted implant. It is found that laser treatment leads to a roughness lower than that of sandblasted dental screws but significantly higher than that of mechanically polished implants. Differences in the roughness at different topological sites show the need for more precise treatment of implants in order to optimize the roughness. [ABSTRACT FROM AUTHOR]