Advanced Materials Interfaces最新文献

Frictional losses play a major role in global energy consumption, making control of friction across length scales essential for improving efficiency. Since friction at the mesoscale often originates from processes at the nanoscale, understanding and controlling nanoscale friction is key to designing low-friction, high-performance materials. Here, nanoscale friction in [LaMnO₃]_m/[SrMnO₃]_n superlattice films using lateral force microscopy is investigated, focusing on the effects of fluorine doping and top-layer thickness. Across all films, the friction force scales linearly with the sum of the applied normal load and adhesion force. While absolute friction forces vary locally due to adhesion variations, the friction coefficient remains consistent for each film but is systematically influenced by fluorine concentration and top-layer thickness. The thickness dependence indicates that frictional energy dissipation extends up to ≈5 nm below the surface, underscoring the role of subsurface structure. This dissipation is attributed to viscoelastic losses in the stress field and evanescent waves generated by the sliding tip, which quantitatively explain the observed friction coefficients. These results demonstrate that, once adhesion is accounted for, the friction coefficient is a reproducible material property that can be systematically tuned—offering a general strategy for tailoring frictional behavior through controlled surface and subsurface modifications.

The uniform orientation of π-conjugated chromophores in thin films is critical for anisotropic charge, energy, and mass transport, with direct implications for optoelectronic and sensing applications. In this study, the molecular orientation and supramolecular organization of a linear amphiphilic BOPHY dye in Langmuir monolayers at the air-water interface are investigated. By combining in situ X-ray reflectivity (XRR), grazing incidence X-ray diffraction (GIXD), and classical molecular dynamics (MD) simulations, the structural evolution of the monolayer through two distinct condensed phases is elucidated. GIXD reveals that the alkyl chains primarily determine the packing density, forming short-range hexagonal domains upon compression, while the chromophores remain locally ordered but lack long-range crystallinity. These results indicate that molecular tilting and bending arise from asymmetries between the BOPHY chromophore and the three alkyl chains. MD simulations further reveal coplanar π-stacked BOPHY dimers or small aggregates with angular distributions that differ between the two phases. The strong agreement between experiment and simulation provides a comprehensive understanding of the alignment of the linear chromophores at the air-water interface and establishes this integrated approach as a powerful framework for predicting and designing functional chromophore assemblies in 2D molecular films.

Dental implants are the standard for replacing missing teeth, with the Ti-6Al-4V alloy dominating the market due to its superior osteointegration. However, long-term implant success is often hindered by peri-implantitis, which stems from bacterial colonization and biofilm formation. To address this challenge, titanium-copper (Ti-Cu) alloys garner attention for their dual antibacterial and osteogenic properties. This review organizes and explores the antibacterial mechanisms of Ti-Cu alloys and their role in promoting osteogenesis in comparison to conventional alloys. Key findings from existing literature underscore the potential of Ti-Cu alloys to enhance implant performance and longevity. Although the literature is promising, further research is needed to determine optimal composition ranges that balance biocompatibility, mitigate cytotoxicity from copper ion release, and facilitate clinical translation. Ti-Cu alloys represent a transformative approach to improving implant outcomes and addressing the limitations of current materials.

Conducting polymers, such as polypyrrole (PPy), are promising coatings for biodegradable vascular implants due to their electrical conductivity and drug-loading capacity. However, their compatibility with cells is not well understood, especially under different synthesis conditions toward endothelial cells. In this study, the effects of deposition parameters and dopants on the viability of human umbilical vein endothelial cells (HUVECs) are systematically examined. PPy coatings are applied to iron substrates using pyrrole (Py, 0.1–0.3 m) and doped with salicylate (SS, 0.1–0.3 m) or dexamethasone (DEX, 0.1–3 mm), with potentials from 1.0 to 1.6 V and deposition charges up to 2.4 C. Coatings prepared at 1.2 V with 0.1 m Py and 0.1 m SS demonstrate the highest biocompatibility conversely, higher voltages or charges produced overoxidized, less conductive films with increased cytotoxicity. SS causes dose-dependent toxicity, while DEX enhanced biocompatibility and reduces surface roughness. HUVECs with low confluence (proliferative) are more sensitive than high-confluence (quiescent) cells. The results reveal a self-powered drug release mechanism driven by Fe/PPy microgalvanic coupling and redox-triggered dopant elution. These findings underscore the importance of optimizing synthesis conditions to balance conductivity, adhesion, and cytocompatibility for safe endothelial applications.

The development of highly efficient semiconducting materials is essential for achieving the high-yield and stable hydrogen and/or oxygen evolution reactions (HER/OER) in photoelectrochemical (PEC) water splitting reactions. The SrTiO₃-TiO₂ eutectic compound has recently emerged as a perspective material with extraordinary activities in the PEC field due to the unique crystallographic and electronic properties caused by the large number of oxygen vacancies in the bulk. In the present study, different experimental techniques (XPS, SEM/EDX, TEM/EDX) are used to provide a detailed investigation of the changes in the structural and electronic properties of the SrTiO₃-TiO₂ eutectic upon annealing under various gaseous environments (in vacuum, air, oxygen, argon). These results demonstrate that thermal annealing in different environments significantly enhances the formation of a sharp interface between the two crystalline phases and allows to control the concentration of the oxygen vacancies within the eutectic material.

Infrared Thermography

The airbrush method is a novel, affordable, black paint preparation method which can achieve thin and high emissivity coatings. The image shows the airbrush being used to paint the cover. The background is an atomic force microscopy image of a prepared black paint coating. More details can be found in the Research Article by Hana Uršič and co-workers (DOI: 10.1002/admi.202500467).

All-solid-state batteries (ASSBs) have gained much interest in recent years because they promise higher energy and power densities as well as improved safety over lithium-ion batteries (LIBs). This is achieved by using non-flammable solid electrolytes (SEs) together with lithium metal or high-capacity silicon anodes. One major hurdle to overcome is the permanent intimate contact of all cell components to enable long-term cycling stability. This study investigates the macroscopic (microstructure) and microscopic (atomistic) effects of uniaxial stack pressure on the transport properties of free-standing, slurry-processed tetragonal $�{\mathrm{Li}}_7$$�{\mathrm{SiPS}}_8$ (t-Li₇SiPS₈) sheets, containing different solid electrolyte (SE)-to-binder ratios (SE:B) and particle size fractions. The results demonstrate that binder content and particle size significantly influence the morphology as evidenced by synchrotron-radiation computed tomography (CT), pressure response, and ionic conductivity of the sheets. Notably, while compression mechanics are consistent across samples, relative densities, and ionic conductivities are more dependent on binder content than particle size. Larger particles and lower binder contents generally led to higher ionic conductivities. The study also reveals that activation volumes appear to increase with binder content, suggesting that extrinsic factors, particularly the binder, may obscure the calculation of the intrinsic activation volumes of t-Li₇SiPS₈. Thus, the obtained values for binder-containing sheets may be considered apparent values. Contrary to expectations, repeated compression cycles led to a decreased ionic conductivity and relative density, likely due to microstructural damage and increased (apparent) activation volumes. Overall, the study serves as a reminder to the community to carefully interpret intrinsic values, such as the activation volume, and by extension the activation energy, in the increasingly popular binder-containing SE sheet systems.

Efficient charge transfer at heterostructure interfaces is crucial for optoelectronic devices. Quasi-2D perovskites with varied layer thicknesses form multiple interfaces, hindering transport. Transient absorption spectroscopy reveals strategic phase distribution enables ultrafast energy transfer across phases and narrow-band emission from high-n phases. Photocurrent and surface potential change indicates directional charge transport exhibits in Quasi-2D perovskites, underscoring the impact of phase distribution on device performance. More details can be found in the Research Article by Sachin R. Rondiya and co-workers (DOI: 10.1002/admi.202500108).

Microscopic carbon/SiO₂ composites are composed of a huge number of interfacial contacts. When those are exposed to moderate ohmic fields gas adsorptivity of the composite is modulated. Herein it shows that it is possible to manipulate, modify, and follow gas adsorption selectivity by in situ spectroscopy under electrical charging. In a model gas mixture of CO₂ and N₂, for the first time it can be shown that a change in gas composition is observed and can be controlled locally above an electrically charged carbon/SiO₂ surface using in situ Raman spectroscopy. The technique is implemented in an ongoing non-stationary adsorption process using the advantage of the fast on-off switchability of the electric field as compared to the typically slow equilibration kinetics of adsorption on activated carbon. An increase in gas phase concentration of 3.5% and 5.5% of CO_2, which is equivalent to a change in selectivity of 11% and 24% of CO₂ over N_2, just by applying an electrical input power of 0.53 and 1.12 W is achieved and quantified by Raman spectroscopy, respectively. The method bears general potential for mixtures of gases with different responses to the electric field, as well as for processes where a local manipulation of gas concentrations is necessary.

Semiconductor thin films are foundational to a broad range of optoelectronic technologies. Solution deposition offers a low-cost, energy-efficient alternative to vapor-based methods, but its practical scalability is hindered by poor reproducibility and high defect densities arising from complex interdependencies among processing variables. Statistical design of experiments (DoE) enables critical insight into the non-intuitive interdependencies that are not accessible by conventional one-variable-at-a-time (OVAT) approaches. Using Sb₂Se₃ as an example semiconductor, DoE is employed with a central composite design (CCD) to systematically vary six processing parameters encompassing ink formulation and deposition parameters. From only 77 experiments, predictive models are constructed for four macro- and microscopic defect types known to interrupt charge transport. All six variables are found to significantly and synergistically influence film quality and are optimized to minimize defect density. Importantly, the optimal film exhibited a threefold enhancement in photoresponse in single-junction devices with no detectable change in composition, nanostructure, or film stability, implicating defect suppression as the critical driver of improved performance. This work highlights DoE as a powerful methodology for uncovering latent structure–processing–property relationships in thin films and provides a general framework for accelerating the development of optoelectronic-grade materials via solution processing.