Search Results (595)

Cell morphology and its mechanical properties are crucial factors in cancer development, affecting migration, invasiveness, and the potential risk of metastasis. However, most studies address these aspects separately, limiting the understanding of how morphological complexity relates to cellular mechanics. This work presents an integrated approach that simultaneously quantifies morphology and viscoelasticity in the human osteosarcoma cell line MG-63. Stress–relaxation experiments and optical imaging of the same cells were performed using a custom-built system that couples Atomic Force Microscopy (AFM) with an inverted optical microscope. Morphometric parameters were extracted from cell contours, while viscoelastic properties were obtained by fitting AFM data to the Fractional Kelvin (FK) and Fractional Zener (FZ) models. Among the morphological descriptors, the Shape Complexity (SC) was proposed. It is derived from the Lobe Contribution Elliptical Fourier Analysis (LOCO-EFA), which captures fine-scale contour features overlooked by conventional metrics. Experimental results show that, in MG-63 cells, higher SC values are associated with greater stiffness, indicating a correlation between cell shape complexity and cell stiffness. Furthermore, loading-rate analysis shows that the FZ model captures strain-rate-dependent stiffening more effectively than the FK model. This methodology provides a first approach to jointly analyzing quantitative morphological parameters and mechanical properties, underlining the importance of combined studies to achieve a comprehensive understanding of cell behavior. Full article

This study investigated the effects of pH (3, 5, 7, 9, 11) on the structure–activity relationship and stability mechanism of Pickering emulsions stabilized by the gorgon euryale starch–quinoa protein complex. Analyses were performed using reverse compression test, rheology, thermal stability assessment, atomic force microscopy (AFM), and low-field nuclear magnetic resonance (LF-NMR) measurements. Reverse compression test showed that the emulsion at pH 3 exhibited the highest hardness and consistency, but the weakest cohesiveness. Rheological measurements revealed that all emulsions displayed shear-thinning behavior, the emulsion at pH 3 had the highest shear stress and apparent viscosity, while that at pH 11 showed the lowest viscosity due to the destruction of macromolecular structures. Thermal stability assessment indicated that the emulsion at pH 3 did not undergo significant stratification even at 60 °C, whereas the stability of emulsions decreased between pH 5–9. Microscopic analyses (optical microscopy, AFM, and LF-NMR) further confirmed that the emulsion at pH 3 had fine, uniform droplets, strong water-binding capacity, and an interfacial film with a “dense protrusion” structure. This study provides a basis for the environmental adaptability design of functional emulsions and contributes to the high-value utilization of gorgon euryale and quinoa resources. Full article

Most insects secrete special fluids from their tarsal pads which are essential for the function of their attachment systems. Previous studies investigated several physical and chemical characteristics of this pad fluid in different insect species. However, there is not much known about the mechanical properties of fluid from smooth adhesive pads. In this study, we used the stress–relaxation nanoindentation method to examine the viscoelastic properties of pad fluid from Sungaya aeta. Force–displacement and stress–relaxation curves on single fluid droplets were recorded with an atomic force microscope (AFM) and analyzed using Johnson–Kendall–Roberts (JKR) and generalized Maxwell models for determination of effective elastic modulus (E), work of adhesion (Δγ) and dynamic viscosity (η). In addition, we used white light interferometry (WLI) to measure the maximal height of freshly acquired droplets. Our results revealed three different categories of droplets, which we named “almost inviscid”, “viscous” and “rigid”. They are presumably determined at the moment of secretion and retain their characteristics even for several days. The observed mechanical properties suggest a non-uniform composition of different droplets. These findings provide a basis for advancing our understanding about the requirements for adaptive adhesion-mediating fluids and, hence, aid in advancing technical solutions for soft or liquid temporal adhesives and gripping devices. Full article

For the method of focused ion beam (FIB) milling to fabricate lithium tantalate (LiTaO₃) metasurfaces, the use of a Cr-Pt mask can enhance imaging contrast and enable superior drift correction. However, removing the Pt component necessitates the volatile and toxic etchant aqua regia, presenting considerable safety risks. This work introduces a novel lift-off strategy that incorporates thin Ag or Au sacrificial layers (≤30 nm) between the LiTaO₃ substrate and Cr-Pt mask. Systematic evaluation identifies Ag or Au as optimal candidates due to their high sputtering yield for efficient FIB patterning and compatibility with a low-toxicity KI + I₂ etchant. Experiments showed complete mask removal within 60 s while preserving structural fidelity: atomic force microscopy (AFM) results reveal a surface roughness comparable to conventional aqua regia processing, and scanning microscope (SEM) imaging confirms intact sidewall angles (10–11°). The second-harmonic generation (SHG) measurements reveal comparable optical performance upon the introduction of Ag or Au sacrificial layers. This approach eliminates hazardous etchant and maintains process precision, offering a scalable and safer fabrication route for LiTaO₃-based photonic devices. Full article

The present study examined the microstructure and corrosion characteristics of MgCa4Zn1Gd1 and MgCa2Zn1Gd3 alloys that were coated with ZnO thin films, which were deposited by atomic layer deposition (ALD). Coatings of different thicknesses (42.5, 95.4 and 133.7 nm for 500, 1000, and 1500 cycles, respectively) were characterized using X-ray diffraction (XRD), Raman spectroscopy, SEM/EDS, AFM (atomic force microscope), and FTIR (Fourier transform infrared spectroscopy). XRD and Raman analyses were conducted to verify the formation of crystalline zinc oxide (ZnO) with a homogeneous granular morphology. Surface roughness decreased with increasing coating thickness, reaching the lowest values for the 1500-cycle ZnO layer on MgCa2Zn1Gd3 (R_a = 7.65 nm, R_s = 9.8 nm). Potentiodynamic and immersion tests in Ringer solution at 37 °C revealed improved corrosion resistance for thicker coatings, with the lowest hydrogen evolution (20.89 mL·cm⁻²) observed for MgCa2Zn1Gd3 coated after 1500 cycles. Analysis of corrosion products by FTIR identified Mg(OH)₂ and MgCO₃ as dominant and then MgO and ZnO. Phase analysis also indicated the presence of ZnO coating after 100 h of immersion. The ZnO film deposited after 1500 ALD cycles on MgCa2Zn1Gd3 provides the most effective corrosion protection and is a promising solution for biodegradable magnesium implants. Full article

Thin films of nickel oxide (NiO) were deposited on a 5° miscut magnesium oxide (MgO)(100) substrate using electron-beam evaporation to pursue morphology-directed resistive switching. The atomic force microscope (AFM) confirmed a stepped surface with a terrace width of ~85 nm and a step height of ~7 nm. After deposition, the film resistance decreased from 200 MΩ to 25 MΩ by annealing under ambient air at 400 °C, attributed to the increase in the p-type conductivity through nickel vacancy formation. Top electrodes of Ag (500 nm width, 180 nm gap) were patterned parallel or perpendicular to the substrate steps using UV and electron-beam lithography. Devices aligned parallel to the step showed reproducible unipolar switching with 100% yield between forming voltages 20–70 V and HRS/LRS~10² at ±5 V. In contrast, devices formed perpendicular to the steps (8/8) subsequently failed catastrophically during electroforming, with scanning electron microscopy (SEM) showing breakdown holes on the order of ~100 nm at the step crossings. The anisotropic electrodynamic response is due to step-guided electric field distribution and directional nickel vacancy migration, illustrating how substrate morphology can deterministically influence filament nucleation. These results highlighted stepped MgO as a template to engineer the anisotropic charge transport of NiO, exhibiting a reliable ReRAM as well as directional electrocatalysis for energy applications. Full article

Utilizing waste tire crumb rubber (CR) in asphalt modification is a promising method to enhance pavement performance while addressing the issue of waste tire disposal. Elevating CR content without compromising the pavement performance of asphalt is crucial for its practical and sustainable applications. However, conventional crumb-rubber-modified asphalt (CRMA) exhibits weakened physical and pavement properties when the CR content exceeds 25 wt%. Here, we propose a hybridization strategy combining CR and devulcanized CR (DCR) to produce high-performance modified asphalt with a total rubber content of up to 43 wt%. Modified asphalt containing 30 wt% CR and 13 wt% DCR (30CR-13DCRMA) demonstrates remarkable physical properties, with a softening point of 78.4 °C and a ductility of 15.33 cm. Rheology tests further reveal its superior rutting resistance (G*/sin δ), fatigue tolerance (G*·sin δ), and overall pavement performance compared to neat CR- or DCR-modified asphalt. Through rheological analysis, sol fraction measurement, gel permeation chromatography (GPC), and atomic force microscope (AFM) tests, it is revealed that the synergistic effect of CR and DCR can enhance the absorption capabilities of rubber particles, promoting their full swelling and resulting in a biphasic hard/soft microstructure within the asphalt matrix. This structural reorganization contributes to the outstanding comprehensive properties of this modified asphalt. This work establishes a hybrid-rubber asphalt system with high CR incorporation and well-balanced performance, offering a viable pathway toward sustainable pavement engineering. Full article

The control of the quantities of multi-tonnage polymers, in particular, making them biodegradable, is an urgent task. This study suggests a new approach in the application of natural rubber (NR) as an initiator of biodegradation of low-density polyethylene (LDPE) in soil. The study examines the structure, properties and rates of biodegradation of thin LDPE films with different content of NR. Such methods as fourier transform infrared spectroscopy (FTIR), electron paramagnetic resonance (EPR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscope (SEM), atomic force microscopy (AFM), gel-permeation chromatography (GPC), and acoustic microscopy were used for the most complete characterization of NR/LDPE composite systems. It was shown for the first time that at concentrations above 30%, NR is able to form an interpenetrating structure with the LDPE matrix, which has a decisive effect on the initiation of biodegradation during exposure in soil. Thus, the composition with 50% natural rubber exhibits the highest mass loss. The sample with 50% natural rubber content lost 70% of its mass, while the one with 40% NR content lost 38%. Furthermore, after soil burial, a significant decrease in crystallinity was observed: from 39.5% to 31.5% for the 90/10 composition and from 39.1% to 24.2% for the 50/50 composition. The results obtained are confirmed by a noticeable decrease in the molecular weight characteristics of LDPE. Full article

Graphene exhibits great potential as an anti-friction coating material in MEMS. However, its underlying microscopic friction-reduction mechanism remains unclear. In this paper, the microstructural evolution and nanomechanical behavior of graphene coatings on copper substrates were systematically investigated by AFM friction experiments and MD simulations. MD simulations reveal that the anti-friction properties of graphene coatings primarily stem from microstructural regulation and load-bearing reinforcement of the substrate. The graphene coatings increase indentation diameter by forming transition radii at the indentation edges, and suppress the plowing effect of the substrate by restricting atomic upward movement, both of which enhance the dislocation density and load-bearing capacity of the substrate. Additionally, graphene coatings also reduce the scratch edge angle, weakening the interlocking effect between the substrate and tip, further lowering the friction force. Experimental results indicate that the tribological behavior of graphene coatings exhibits staged characteristics: graphene coatings show excellent ultrafriction properties under intact structural conditions, while showing a higher friction force in wear and tear states. This research provides a theoretical basis and technical guidance for the development of anti-friction and wear-resistant coatings for micro-nano devices. Full article

Deicing salt effectively melts ice and snow to maintain traffic flow in seasonal freezing zones, but its erosion effect compromises the water stability and structural integrity of asphalt pavements. To comprehensively explore the impacts of salt erosion on the interfacial behaviors of rubber asphalt–aggregate systems, this study developed a multiscale characterization method integrating a macroscopic mechanical test, microscopic tests, and molecular dynamics (MD) simulations. Firstly, laboratory-controlled salt–freeze–thaw cycles were employed to simulate field conditions, followed by quantitative evaluation of interfacial bonding properties through pull-out tests. Subsequently, the atomic force microscopy (AFM) and Fourier transform infrared spectrometer (FTIR) tests were conducted to characterize the microscopic morphology evolution and chemical functional group transformations, respectively. Moreover, by combining the diffusion coefficients of water molecules, salt solution ions, and asphalt components, the mechanism of interfacial salt erosion was elucidated. The results demonstrate that increasing NaCl concentration and freeze–thaw cycles progressively reduces interfacial pull-out strength and fracture energy, with NaCl-induced damage becoming limited after twelve salt–freeze–thaw cycles. In detail, with exposure to 15 freeze–thaw cycles in 6% NaCl solution, the pull-out strength and fracture energy of the rubber asphalt–limestone aggregate decrease by 50.47% and 51.57%, respectively. At this stage, rubber asphalt exhibits 65.42% and 52.34% increases in carbonyl and sulfoxide indexes, respectively, contrasted by 49.24% and 42.5% decreases in aromatic and aliphatic indexes. Long-term exposure to salt–freeze–thaw conditions promotes phase homogenization, ultimately reducing surface roughness and causing rubber asphalt to resemble matrix asphalt morphologically. At the rubber asphalt–NaCl solution–aggregate interface, the diffusion of Na⁺ is faster than that of Cl⁻. Meanwhile, compared with other asphalt components, saturates exhibit notably enhanced mobility under salt erosion conditions. The synergistic effects of accelerated aging, salt crystallization pressure, and enhanced ionic diffusion jointly induce the deterioration of interfacial bonding, which accounts for the decrease in macroscopic pull-out strength. This multiscale investigation advances understanding of salt-induced deterioration while providing practical insights for developing durable asphalt mixtures in cold regions. Full article

Thermoelectric (TE) materials represent a critical frontier in sustainable energy conversion technologies, providing direct thermal-to-electrical energy conversion with solid-state reliability. The optimizations of TE performance demand a nuanced comprehension of structure–property relationships across diverse length scales. This review summarizes established and emerging spectroscopic and microscopic techniques used to characterize inorganic and polymer TE materials, specifically poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS). For inorganic TE, ultraviolet–visible (UV–Vis) spectroscopy, energy-dispersive X-ray (EDX) spectroscopy, and X-ray photoelectron spectroscopy (XPS) are widely applied for electronic structure characterization. For phase analysis of inorganic TE materials, Raman spectroscopy (RS), electron energy loss spectroscopy (EELS), and nuclear magnetic resonance (NMR) spectroscopy are utilized. For analyzing the surface morphology and crystalline structure, chemical scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) are commonly used. For polymer TE materials, ultraviolet−visible–near-infrared (UV−Vis−NIR) spectroscopy and ultraviolet photoelectron spectroscopy (UPS) are generally employed for determining electronic structure. For functional group analysis of polymer TE, attenuated total reflectance–Fourier-transform infrared (ATR−FTIR) spectroscopy and RS are broadly utilized. XPS is used for elemental composition analysis of polymer TE. For the surface morphology of polymer TE, atomic force microscopic (AFM) and SEM are applied. Grazing incidence wide-angle X-ray scattering (GIWAXS) and XRD are employed for analyzing the crystalline structures of polymer TE materials. These techniques elucidate electronic, structural, morphological, and chemical properties, aiding in optimizing TE properties like conductivity, thermal stability, and mechanical strength. This review also suggests future research directions, including in situ methods and machine learning-assisted multi-dimensional spectroscopy to enhance TE performance for applications in electronic devices, energy storage, and solar cells. Full article

We report combined scanning probe microscopy and electrical measurements to investigate local electronic transport in reduced graphene oxide (rGO) devices. We demonstrate that quantum transport in these materials can be significantly tuned by the electrostatic potential applied with a conducting atomic force microscope (AFM) tip. Scanning gate microscopy (SGM) reveals a clear p-type response in which local gating modulates the source–drain current, while scanning impedance microscopy (SIM) indicates corresponding shifts of the Fermi level under different gating conditions. The observed transport behavior arises from the combined effects of AFM tip-induced Fermi-level shifts and defect-mediated scattering. These results show that resonant scattering associated with impurities or structural defects plays a central role and highlight the strong influence of local electrostatic potentials on rGO conduction. Consistent with this electrostatic control, the device also exhibits chemical gating and sensing: during exposure to electron-withdrawing molecules (acetone), the source–drain current increases reversibly and returns to baseline upon purging with air. Repeated cycles over 15 min show reproducible amplitudes and recovery. Using a simple transport model, we estimate an increase of about $40\%$ in carrier density during exposure, consistent with p-type doping by electron-accepting analytes. These findings link nanoscale electrostatic control to macroscopic sensing performance, advancing the understanding of charge transport in rGO and underscoring its promise for nanoscale electronics, flexible chemical sensors, and tunable optoelectronic devices. Full article

The microstructures and mechanical and corrosion properties of Mg-12Gd-2Zn-xNd-0.4Zr (x = 0, 0.5, and 1.0 wt.%) alloys after hot-extrusion have been studied by scanning electron microscope (SEM), transmission electron microscope (TEM), electron back scattered diffraction (EBSD), X-ray diffractometer (XRD), electronic universal testing machine, atomic force microscope (AFM), immersion, and electrochemical tests. The results show that all the alloys consist of an α-Mg matrix, β phase, and stacking faults (SFs). Obvious texture (<$\overline{1}2\overline{1}0$> parallel to the extrusion direction and the direction close to <0001>) can be found due to the introduction of the Nd element. The yield strength (YS) of the alloys with Nd additions in different testing conditions is higher than that without Nd addition. The addition of 0.5 wt.% Nd achieves the highest tensile YS at room temperature (262 MPa) and 180 °C (251 MPa), along with compression YS (246 MPa), attributable to grain refinement, stacking faults, texture, and solute atom strengthening. Moreover, the compression YS to tensile YS ratio of the as-extruded alloy increases from 0.87 to 0.98, indicating a significant improvement of tension–compression YS asymmetry. The Nd addition also plays a great role in the enhanced corrosion resistance of the alloys. Specifically, the corrosion potential of the different phases in the alloys shows the following order: β phase > SFs > α-Mg matrix. The alloy with 0.5 wt.% Nd addition exhibits the best corrosion resistance owing to its lower corrosion potential difference between the β phase and α-Mg matrix. Full article

In view of the need to increase the durability of working tools exposed to intense friction, this study analysed hybrid coatings (TiAlCN, AlTiCN, AlCrTiN, TiN, CrN) with a DLC (Diamond-Like Carbon) layer, deposited using PVD (Physical Vapour Deposition) methods (arc evaporation and magnetron sputtering). The structural characteristics of the coatings were determined using SEM (Scanning Electron Microscope) and AFM (Atomic Force Microscope) microscopy, as well as Raman spectroscopy, which confirmed the compact structure and amorphous nature of the DLC layer. Tribological tests were performed using a ball-on-disc test, revealing that DLC hybrid coatings significantly reduce the coefficient of friction (stabilisation in the range of 0.10 to 0.14 due to DLC graphitisation), limiting tool wear even under increased load. The SEM-EDS (Scanning Electron Microscope-Energy Dispersive Spectroscopy) microscopic examination revealed that the dominant wear mechanisms are abrasive and adhesive damage, and the AlCrTiN/DLC system is characterised by low wear and high adhesion (L_c = 10⁵ N), making it the optimal configuration for the given loads. Microhardness tests showed that high hardness does not always automatically translate into increased wear resistance (e.g., the AlTiCN coating with 4220 HV showed the highest wear), while coating systems with moderate hardness (TiAlCN/DLC, CrN/DLC) achieved very low wear values (~0.17 × 10⁻⁵ mm³/Nm), which highlights the importance of synergy between the hardness of the sublayer and the low friction of DLC in the design of protective coatings. Full article

Diamond is a promising next-generation semiconductor material, offering a wider band gap, higher electron mobility, and superior thermal conductivity compared with silicon. However, its exceptional hardness makes it challenging to fabricate. In this study, we demonstrate a novel approach to realize material removal on hydrogen-terminated diamond surfaces by atomic force microscope (AFM) tip-based local anodic oxidation. By adjusting both the applied voltage and hydrogen plasma etching parameters, the material is removed over an area larger than the AFM tip size. Notably, the hardness of the material surrounding the removal zone is significantly reduced, enabling it to be scratched with a silicon tip. These findings open a promising pathway for improving the machinability of diamonds in future device applications. Full article