Advanced Materials Interfaces最新文献

Solution-based atomic layer deposition (sALD) is an emerging technique that transfers the principle of traditional atomic layer deposition (ALD) from the gas phase into a wet chemical environment. This new preparation technique has new and unique properties and requirements. A large number of new surfaces and reactants are available to produce active 2D materials.

In this work a reproducible procedure to coat silicon wafers with a densely packed monolayer of (3-Mercaptopropyl)trimethoxysilane (MPTMS) molecules is presented. These highly functionalized surfaces can be used to seed the nucleation of SnS₂ in a solution-based ALD procedure. A coating routine for the production of SnS₂ is adapted from ALD to sALD and insight into the nucleation behavior of the reactands is given. X-ray reflectometry (XRR) is used to resolve the nucleation process of SnS₂ on an MPTMS self assembled monolayer (SAM) during the first three cycles of an sALD procedure. The comparison of ex situ XRR, in situ XRR, grazing incidence wide-angle X-ray scattering (GIWAXS), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDX) measurements, and density functional theory (DFT) calculations find that SnS₂ first forms a closed layer and then continues to grow in islands on thiol functionalized silane SAMs. Subsequent coating cycles will continue the growth of the islands laterally and in height.

Fracture non-union occurs due to various factors, leading to the development of potentially substantial bone defects. While autograft and allograft are the current gold standards for non-union fractures, challenges related to availability and immune rejection highlight the need for improved treatments. A strategy in bone tissue engineering is to harness growth factors to induce an effect on cells to change their phenotype, behavior and initiate signaling pathways which lead to increased matrix deposition and tissue formation. Bone morphogenetic protein-2 (BMP-2) is a potent osteogenic growth factor however, given its rapid clearance time in vivo, there is a specific therapeutic window for efficacy while avoiding potential deleterious side-effects. It is demonstrated that a Laponite nanoclay coating on a 3D printable and bioresorbable poly(caprolactone) trimethacrylate-based resin enables binding of BMP-2, decreases the rate of release, enabling reduced concentrations to be used while enhancing osteoinduction in both in vitro and in vivo models.

The crystalline quality and degree of c-axis orientation of hexagonal AlN thin films correlate directly with their functional properties. Therefore, achieving AlN thin films of high crystalline quality and texture is of extraordinary importance for many applications, but particularly in electronic devices. This systematic study reveals, that the growth of c-axis-orientated AlN thin films can be governed by a chemical stabilization effect in addition to the conventionally known structural, strain-induced, stabilization mechanism. The promotion of in-plane growth of AlN grains with c-axis out-of-plane orientation is demonstrated on Y, W, or Al seed layers with different thicknesses and crystallinity preliminary exposed to N₂ at room temperature. It is established that the stabilization mechanism is chemical in nature: the formation of an N-rich surface layer on the metal seed layers upon exposure to N₂ pre-determines the polarity of AlN islands at the initial stages of thin film growth while the low energy barrier for the subsequent coalescence of islands of the same polarity contributes to grain growth. These results suggest that the growth of c-axis oriented AlN thin films can be optimized and controlled chemically, thus opening more pathways for energy-efficient and controllable AlN thin film growth processes.

Control of exposed crystal facets in nanostructures is scientifically important, but technically challenging due to the inherent difficulty in manipulating surface energy of crystals. Here, laser-induced periodic surface structures (LIPSS) induced by femtosecond laser is applied to produce periodic subwavelength 1D nanostructures with high index crystal facets on epitaxial CoFe₂O₄ surfaces, providing an efficient, maskless, cost-effective “top-down” method for nanostructure fabrication. Homogenous 1D LIPSSs (1D-LIPSSs) with a period of 131 ± 15 nm and a depth of 90 ± 5 nm are obtained. The orientation of LIPSS nanostructures is finely controlled by tuning the polarization of fs laser beam, therefore flexibly producing 1D-LIPSSs along various crystallographic orientations. Gas sensing performance evaluation shows that the fabrication of 1D-LIPSSs on CoFe₂O₄ enlarges its surface area and contributes to enhanced gas sensing response. Compared to CoFe₂O₄ with LIPSSs faceted along {100} orientation, CoFe₂O₄ with LIPSSs faceted along high-index {110} facets exhibits further improved gas sensing performance, suggesting the critical role of high-index crystal facets in promoting surface reactivity and sensing sensitivity. The development of a laser-based nanostructure fabrication route with high controllability of exposed crystal facets provides a novel solution for high-density film-based gas sensing applications.

Vesicle Immobilization

Vesicles filled with chemosensors are immobilized into regular arrays on a polymer brush antifouling surface. Analytes entering the vesicle can turn off the chemosensor fluorescence. In article 2400200, Michael Hirtz and co-workers investigate the stability of these systems and their potential for membrane permeability assays.

Industrial Manufacturing

Metallic single-walled carbon nanotubes networks on the surface and inside the pores of polysulfone substrates are manufactured in industrial scale to support sub-10 nm polyamide reverse osmotic desalination membranes for high performance that are demonstrated in spiral wound elements. The industrial scale manufacturing of PA nanofilm is saving materials at low fabrication expenses. More details can be found in article 2400168 by Huaping Li and co-workers.

Improving the efficiency of bifunctional electrocatalysts is a decisive challenge in the area of long-lasting rechargeable zinc-air batteries. Enhancing the catalysts' performance is crucial for advancing zinc-air batteries. Transition-metal oxides have emerged as promising non-precious, noble-metal-free catalysts. Herein, a unique precursor directed approach is introduced for preparing a cobalt ferrite@nitrogen doped carbon nanohorns (CoFe₂O₄@N-CNHs) nanohybrid catalyst in a single step annealing process involving stoichiometric amounts of single-source cobalt and iron molecular precursors and carbon nanohorns (CNHs) under an argon/ammonia (Ar/NH₃) atmosphere. This procedure enables a simultaneous CoFe₂O₄ ferrite synthesis and nitrogen functionalization of CNHs. The precious metal free nanohybrid CoFe₂O₄@N-CNHs-30% containing 30% of carbon presents an oxygen reduction reaction (ORR) half wave potential and onset potential comparable to the standard ORR catalyst 20% Pt/C. CoFe₂O₄@N-CNHs-30% also establishes superior oxygen evolution reaction (OER) performance with a low overpotential and a small Tafel slope than benchmark OER catalyst RuO₂. Furthermore, the rechargeable zinc-air battery with the CoFe₂O₄@N-CNHs-30% nanohybrid as air electrode demonstrates steadier and more durable charge–discharge cycles, and outstanding energy density relative to the state-of-the-art 20% Pt/C-RuO₂ catalyst.

The superhydrophobicity of submerged surfaces typically pertains to the trapped air film at the liquid–solid interface, subject to wettability transitions from a Cassie–Baxter state to more unstable states that gradually collapse to high retention regimes, which are energetically more favorable. In this work, the dynamic evolution of those transient metastable states is correlated to the underwater acoustic performance of laser textured superhydrophobic surfaces, resolving the dependence of the ultrasound spectral response with the immersion time to capture the genuine contribution of the hierarchical subwavelength morphology, regardless of the air layer effects. Acoustic wave attenuation of the incident ultrasound energy is extensively quantified in transmission, accounting for instantaneous broadband sound blocking (>30 dB) within the spectral range 0.5–1.5 MHz. As a result of the air layer detachment with the immersion time, transmission coefficients increase accordingly, while acoustic fields in reflection unexpectedly evolve toward stealthiness and naïve acoustic camouflage, mostly ascribable to dissipative mechanisms at air layer interfaces. The intrinsic decay of the air layer effect is tentatively determined at different frequencies, since quantitative understanding of the transient lifetime governing underwater surface wettability is critical to design stable superhydrophobic character of laser induced subwavelength metastructures on the most promising acoustic materials – from eco-friendly natural to artificial.

TiO₂-based composite photocatalysts are currently being explored to address concerns intrinsic to TiO₂, specifically high charge carrier recombination and UV light activation. Among various materials utilized for composite formation, carbon nanomaterials stand out due to their high electron conductivity, charge storage, photosensitization, and surface properties. However, high carbon content in composites has been shown to reduce performance with potential toxicity concerns. To harness the diverse properties of carbon nanomaterials in a single composite while optimizing the carbon content below 1% by weight, multi-walled carbon nanotubes (MWCNT)/TiO₂ sensitized by carbon nanodots (CND) are synthesized. The heterojunction formed between MWCNTs and TiO₂ in the binary composite reduced the charge carrier recombination rate compared to TiO₂. The addition of CNDs to MWCNT/TiO₂ induced visible light absorbance of the resulting ternary composite, due to the forbidden electron transitions undergone in CND aggregates. CND/MWCNT/TiO₂ exhibited a fivefold and 1.6-fold increase in photocatalytic degradation of acid orange 7 and tetracycline under visible light compared to TiO₂. This enhancement is attributed to the photosensitizing property of CNDs working in synergy with the charge storage ability of MWCNTs. A plausible charge transfer pathway for the activity of CND/MWCNT/TiO₂ is proposed.