Advanced Materials Interfaces最新文献

A bilayer of V_0.49N_0.51/V_0.56N_0.44 has been grown epitaxially on MgO(001) by reactive high-power pulsed magnetron sputtering in an industrial-scale deposition system at a temperature of 400°C, and it is demonstrated that the defect structure and interfacial strain are governed by the N concentration. Based on the lattice mismatch between MgO and V_0.49N_0.51 with V vacancies, an interfacial strain of −2.3(1)% is expected. From ab initio calculations, X-ray diffraction, and transmission electron microscopy data, it is inferred that the V_0.49N_0.51 layer exhibits V vacancies, N Frenkel pairs, and a high dislocation density of ≈0.20 nm⁻², causing an interfacial strain of −1.4(5)% at the MgO/V_0.49N_0.51 interface. The phase formation of understoichiometric V_0.56N_0.44 is governed by N vacancy formation, while the dislocation density is reduced to ≈0.04 nm⁻² at the V_0.49N_0.51/V_0.56N_0.44 interface and to < 0.01 nm⁻² within V_0.56N_0.44 at a distance of ≈35 nm from the interface. Based on ab initio calculations, a strain of −1.7(6)% is predicted at the V_0.49N_0.51/V_0.56N_0.44 interface in very good agreement with the experimentally obtained value of −1.6(8)%. It is evident that control of the N concentration allows for the design of layered architectures with well-defined strained interfaces and tailored defect structures.

Lubricating greases play a vital role in reducing friction and wear under dynamic loading, but their performance is often limited by poor dispersion and compatibility of nano-additives. In this study, graphene-coated titanium dioxide (TiO₂@G) hybrids were synthesized via carbothermal treatment and incorporated at 0.5 wt% in lithium grease, alongside pristine graphene, TiO₂, and their physical mixture for comparison. Tribological and thermal behavior were evaluated using ASTM-standard testing, profilometry, transmission electron microscopy and Hamrock–Dowson line-contact film-thickness modeling. The TiO₂@G-800 hybrid demonstrated an 85.7% reduction in wear scar diameter, a 22.0% decrease in operating temperature and a modest increase in calculated film thickness (∼1.5%) relative to the control. Lubrication regime analysis based on Stribeck and Tallian parameter (λ) confirmed mixed lubrication across all samples, with slightly higher λ ratios for TiO₂@G-800 and graphene, consistent with improved film retention and wear protection. The superior performance of TiO₂@G is attributed to its engineered core–shell morphology, wherein the graphene sheath improves interfacial lubricity and thermal conductivity while the TiO₂ core provides structural reinforcement. These findings highlight nanoscale interface engineering as a promising approach for developing next-generation high-performance greases with applications in energy, transportation and advanced manufacturing.

Efficient fog harvesting strategies have attracted increasing attention for addressing global water scarcity. In this study, a bio-inspired slippery surface was engineered by combining hydrophilic–hydrophobic patterning and lubricant infusion based on hydrophobic undecylenic-modified microcrystalline cellulose (UMCC) nanoparticles. The UMCC nanoparticles were synthesized using a dialysis–spraying process, followed by UV-assisted patterning of the hydrophilic domains and infusion with a perfluoropolyether lubricant to create a stable, directionally modified slippery interface. The pristine nanoparticle surface exhibited strong adhesion and high contact-angle hysteresis, which severely hindered droplet removal. However, after lubricant infusion, the contact angle hysteresis was dramatically reduced, enabling rapid droplet mobility, similar to that of Nepenthes pitcher plants. The resulting surface exhibited excellent chemical and environmental stabilities over a wide pH range. Notably, the moderately hydrophilic amino-patterned surface enhanced droplet nucleation, coalescence, and directional removal, achieving an exceptional fog-harvesting rate of 532.8 ± 85.1 mg/(h·cm²), surpassing the performance of all unmodified controls. This study established a simple and sustainable platform for next-generation bio-inspired fog-harvesting and water-management technologies.

A novel atomic layer deposition (ALD) process for highly conducting nickel disulfide thin films is introduced. This simple, sustainable and safe deposition process is based on two solid precursors, nickel acetylacetonate (Ni(acac)₂) and elemental sulfur. The process yields single-phase NiS₂ thin films in the deposition temperature range from 220°C to 270°C, with an appreciably high growth rate of ca. 3.42 Å per cycle. The as-deposited films are highly crystalline and chemically homogeneous. Room-temperature electrical conductivity values up to 2.8 × 10³ S/m and optical bandgap values in the range of 0.8–0.9 eV are measured for the films. The distinctly high surface area of the films, caused by flake-like nanostructures, together with the excellent electrical properties makes the present ALD-grown NiS₂ thin films attractive for various electrochemical applications, such as catalysts for hydrogen evolution reaction.

Organic artificial enzymes, renowned for their stability under non-physiological conditions, have recently attracted attention. In this study, we strategically designed small molecular photo-activated oxidase mimics by incorporating halogen atoms onto styrene-based molecular rotors, termed DAPy-X^m series (X = Cl, Br, and I), to leverage the heavy atom effect and amplify the generation of reactive oxygen species (ROS). In addition, incorporation of halogen atoms at the meta-position of 4-methyl-picolinium unit modulates the internal rotational barrier, thereby enhancing the temperature sensitivity of DAPy-X^m series. Among them, DAPy-I^m exhibited a significant enhancement in generating both superoxide anion (O₂^•−) and singlet oxygen (¹O₂) species. Taking advantage of its unique photo-responsive oxidase-like behavior with cold-adapted property, DAPy-I^m is successfully applied to the visible-light driven synthesis of ergosterol peroxide (EP), a bioactive compound with notable anti-tumor and anti-microbial characteristics. Remarkably, the photo-oxidase activity of DAPy-I^m is significantly improved at low temperatures compared to higher-temperature conditions, highlighting the potential of heavy atom-engineered molecular rotors to achieve an exceptionally low-temperature photocatalytic reaction for synthesizing thermo-sensitive products.

Transient electric birefringence measurements are used to show that brookite titania nanorods dispersed in the apolar liquid butylbenzene possess a large permanent dipole moment of 516 debye (rod length: 39 nm, diameter: 4.1 nm). This dipole moment makes the particles highly susceptible to applied electric fields. Isotropic dispersions at high volume fractions of up to 20% nanorods are aligned on a time scale of tens of microseconds at low field strengths. Alignment becomes nearly complete at a field strength of around 10 V/µm. It is shown that the birefringence of these dispersions is large enough that light transmission can be switched on and off in thin film cells of 150 µm thickness. These properties make brookite nanorod dispersions promising as the active material in optoelectronic applications.

Spheroids have emerged as valuable tools in bone tissue engineering, mimicking the cellular interactions in native tissues. However, the application of small and low-cell-number spheroids for simultaneous bone regeneration and vascularization remains underexplored. In this study, small pre-vascularized spheroids (250 cells each) were developed, using human mesenchymal stem cells (hMSCs) or human periosteum-derived stem cells (hPDCs), co-cultured with human umbilical vein endothelial cells (HUVECs). Spheroids were evaluated for stability, osteogenic differentiation, and angiogenic potential. Results indicated that hMSC and hPDC spheroids formed stable structures, while HUVEC monocultures failed to achieve spheroid stability. Co-cultures showed HUVEC localization patterns mimicking native vascular structures. Gene and protein analyses revealed distinct osteogenic potential between hMSC and hPDC spheroids, with the latter demonstrating superior and earlier differentiation. Additionally, vascular endothelial growth factor expression was higher in co-cultures, suggesting enhanced angiogenic potential, particularly in hPDC spheroids. Using small-diameter spheroids addresses limitations of conventional large spheroids, such as necrotic core formation and heterogeneous differentiation. These findings emphasize the promise of pre-vascularized spheroids for scaffold-free and scaffold-based tissue engineering applications. Furthermore, their small size enables the exploration of their potential applications in 3D bioprinting, paving the way for the future development of more biomimetic vascularized bone constructs.

Adherent cells are highly sensitive to the physical and biochemical properties of their microenvironment, particularly the extracellular matrix (ECM), which regulates cell adhesion, signaling, and overall behavior. Cells also actively modify and remodel the ECM, creating a continuous interaction comparable to a dialogue. Consequently, artificial cell microenvironments are used to influence adherent cell behavior. However, these environments must be carefully modulated to enhance communication with cells. To this end, bio-functionalization of cell culture substrates has been developed to improve interactions between adherent cells and their microenvironment. To optimize cell–biomaterial surface interactions, various protein grafting techniques can be employed, including random grafting via amine groups, semi-oriented grafting via thiol groups, and glycosylation-based grafting. This study specifically focuses on the glycosylation-based grafting method, which creates a natural spacer between the substrate and the immobilized protein. We introduce a novel glycan-based surface functionalization approach using two ECM adhesion proteins commonly used in biomaterials: fibronectin (Fn), a fibrillar protein with low glycosylation (5% w/w), and vitronectin (Vn), a globular protein with high glycosylation (30% w/w). Both proteins are highly purified from human blood plasma to preserve their native state and bioactivity. We analyzed the effects of glycan-based grafting on the conformation and bioactivity of these proteins. Given their essential roles in ECM, human pre-osteoblastic STRO-1⁺A cells are cultured on the bio-functionalized surfaces, and their early-stage behavior is compared for both Fn and Vn. Our results demonstrate that glycosylation-based grafting significantly influences the conformation and bioactivity of Fn and Vn. Cell adhesion, viability, and morphology are assessed, revealing that this grafting method enhances cell–material interactions, making it a promising strategy for improving the performance of biomaterials in biomedical applications.

In-Situ Spectroscopy

This work introduces in situ Raman spectroscopy to monitor the synthesis of phthalocyanine based 2D conjugated MOFs at the air–water interface. Distinct marker bands are identified that reveal linker aggregation versus MOF formation, which are further correlated with crystalline domain size of the MOF using TEM, enabling rapid, non invasive, and reliable quality control throughout the MOF synthesis process. More details can be found in the Research Article by Inez M. Weidinger and co-workers (DOI: 10.1002/admi.202500686).

Local surface potential modification by defect structures in 2D transition metal dichalcogenide (2D-TMDC) is of particular interest for engineering of their optoelectronic and surface chemical properties. Optical irradiation on 2D-TMDC provides facile methodology for the defect structure patterning, however, its effect in surface potential modification has remained largely unexplored. Here, we investigate the changes in surface potential of optical soldering induced defect structures in few-layer MoS₂ by using a Kelvin probe force microscope (KPFM). Measured contact potential difference (CPD) of the defect structures shows Fermi level shift toward conduction band indicating n-doping effect. By correlating CPD with optical soldering laser power and photoluminescence (PL) emission efficiency, we identified two distinct mechanisms governing PL enhancement in two optical soldering laser power regimes. With lower optical soldering powers (<3 mW), defect formation from pristine MoS₂ introduces new edge sites leading to significant PL enhancement with increased CPD. Further increases in optical soldering power show a monotonic rise in CPD accompanied by PL quenching as a result of increased n-doping level. Our results suggest a methodology for optical doping of 2D-TMDC which is relevant to the development of Defect Engineering, Kelvin probe force microscope, optical doping, optical soldering, transition metal dichalcogenidepractical applications such as ultrasensitive chemicals and biosensors.