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The spontaneous generation of hydrogen peroxide (H2O2) within atmospheric microdroplets, such as raindrops and aerosols, plays a crucial role in various environmental processes including pollutant degradation and oxidative stress. However, quantifying hydroxyl radicals (•OH), essential for H2O2formation, remains challenging due to their short lifespan and low concentration. This study addresses this gap by presenting a highly sensitive and selective surface-enhanced Raman scattering (SERS) nanosensor specifically designed for quantifying •OH within water microdroplets. Utilizing a phthalhydrazide (Phth) probe, the SERS technique enables rapid, interference-free detection of •OH at nanomolar concentrations. It achieves a linear detection range from 2 nM to 2 μM and a limit of detection as low as 0.34 nM. Importantly, the SERS sensor demonstrates robustness and accuracy within water microdroplets, paving the way for comprehensive mechanistic studies of H2O2generation in the atmosphere. This innovative approach not only offers a powerful tool for environmental research but also holds potential for advancing our understanding of atmospheric H2O2formation and its impact on air quality and pollutant degradation.

Li-rich layered oxide (LLOs) cathode materials are gaining increasing attention as lithium-ion batteries (LIBs) pursue greater energy density. However, LLOs still suffer from severe capacity fading and voltage decay due to their unstable crystal structure. Hence, the anion–cation dual-ion multisite doping strategy based on Mg and S atoms is used to stabilize the crystal structures of LLOs. Mg substitutes Li atoms in the Li and transition-metal (TM) layers, while S atoms occupy tetrahedral interstitial sites and lattice O sites, all of which contribute to the crystal structure stability of LLOs. Theoretical calculations show that Mg/S dual-ion multisite doping successfully reduces the energy levels of the TM 3d–O 2p and isolated O 2p orbitals, which effectively stabilizes the lattice oxygen. Therefore, multisite-doped samples exhibit promising electrochemical performance. This strategy provides a new approach to enhance the crystal structure stability of LLOs for the design of high-energy-density Li-ion batteries.

Reducing lunar dust adhesion to various material surfaces is important for protecting equipment from damage during lunar exploration missions. In this study, we investigate the lunar dust-mitigation ability and dust adhesion force of aluminum (Al) substrates prepared using different etching methods. Among them, composite etching methods (combining chemical and electrochemical steps) can result in multiscale structures with micro- and nanoroughness, reducing the contact area between the substrate and thus decreasing lunar dust adhesion. After composite etching, the dust adhesion force of the Al substrate was significantly reduced by 80% from 45.53 to 8.89 nN. The dust adhesion force of Al substrates dominates their dust-mitigation performance in floating dust environments. The lunar dust coverage (2.19%) of the Al substrate modified by composite etching (placed with a tilt angle of 90°) was 4-fold lower than that of the pristine Al substrate (9.11%), indicating excellent lunar-dust repellence. In addition, other factors such as tilt angle of the substrate and dust loading significantly affect dust-mitigation performance of the modified Al substrates. The Al substrate with an excellent dust-mitigation ability highlights good potential for lunar exploration missions.

Surface-enhanced Raman spectroscopy (SERS) stands out in the field of microbial analysis due to its rich molecular information, fast analysis speed, and high sensitivity. However, achieving strain-level differentiation is still challenging because numerous bacterial species inevitably have very similar SERS profiles. Here, a method inspired by the black-box theory was proposed to boost the spectral differences, where the undifferentiated bacteria was considered as a type of black-box, external environmental stress was used as the input, and the SERS spectra of bacteria exposed to the same stress was output. For proof of the concept, three types of environmental stress were explored, i.e., ethanol, ultraviolet light (UV), and ultrasound. Enterococcus faecalis(E. faecalis) and three types of Escherichia coli(E. coli) were all subjected to the stimuli (stress) before SERS measurement. Then the collected spectra were processed only by simple principal component analysis (PCA) to achieve differentiation. The results showed that appropriate stress was beneficial to increase the differences in bacterial SERS spectra. When sonication at 490 W for 60 s was used as the input, the optimal differentiation of bacteria at the species (E. faecalisand E. coli) and strain-level (three E. coli) can be achieved.

Although a dust-repellent surface is desirable for lunar exploration missions, its fabrication process is complicated and time-consuming. Herein, we report a simple and fast method to fabricate a lunar dust-repellent surface by texturing on an Al substrate via nanosecond laser etching. The laser-induced photothermal effect can rapidly create hierarchical papillary structures on 25 × 25 mm Al substrates (within 30 s). Both atomic force microscopy (AFM) and in situ scanning electron microscopy (SEM) reveal that such structures enable a reduced contact area between the Al substrate and lunar dust and thus reduced adhesion. The reduced dust adhesion force of Al substrates facilitates improving their antidust performance. By optimizing processing parameters, the Al substrate etched with a laser scanning spacing of 80 μm exhibits a lower dust adhesion force (9.58 nN) due to the smallest contact area with dust. Accordingly, its static antilunar dust performance (dust coverage of 1.95%) is significantly improved compared to the pristine Al substrate (dust coverage of 12.98%). Besides, the accumulated dust on the laser-etched Al substrates with low surface adhesion force is easily cleaned up by flipping and gravity (the dust residual rates are less than 17%). The Al substrate with excellent antidust ability presents good potential for lunar exploration missions.

A fully self-powered bimodal sensor is designed for patterned-displaying the force trajectories.Outstanding mechanoluminescence is achieved with a stimulation force as low as 0.3 N and 2000 cycles reproducibility.The designed bimodal sensor exhibits good potential for handwriting input to achieve visual intelligent control.

Fabrication of a gel polymer electrolyte containing succinonitrile (GPE-SN) with high mechanical strength is quite challenging because the SN electrolyte always suppresses the formation of polymer networks during in situ polymerization. In this work, a mechanically robust GPE-SN was successfully prepared by using a solution immersion method. During fabrication, the paste-like SN electrolyte was transformed into a liquid SN electrolyte with low viscosity by heating at 50 °C and then infiltrated into the UV-cured highly cross-linked polyurethane acrylate (PUA) skeleton. The resulted GPE-SN film exhibits superior tensile strength (6.5 MPa) compared to the one (0.5 MPa) prepared by in situ polymerization (GPE-SN-IN). The high mechanical strength of the GPE-SN-IM film enables the LiCoO2/Li4Ti5O12film battery to withstand 100-cycle folding without electrolyte damage and capacity loss. Besides, the GPE-SN presents a high ionic conductivity (1.63 × 10–3S·cm–1at 25 °C), which is comparable to GPE with a commercial liquid electrolyte (GPE-LE). Because of good thermal stability of the GPE-SN, the LiCoO2/Li cell with this electrolyte shows better charge–discharge cycling stability than that with GPE-LE at high temperature (55 °C). Thus, the GPE-SN prepared by our method could be a promising polymer electrolyte offering better safety and reliability for lithium-ion batteries.

Enhancing surface wetting is very critical for various applications of polymer films. Although existing modification methods (e.g., UV radiation and plasma treatments) can improve the wetting of polymer films by inserting hydrophilic groups, the resultant polymer surface is unstable and shows strong hydrophobic recovery in a short time (less than 1 day) due to the rearrangement of the polymer chains. Herein, we report a new approach to prepare stable wetting surface by cross-linking hydrophilic poly(acrylic acid) (PAA) molecules on poly(chloro-p-xylylene) (PPXC) films via hyperthermal hydrogen induced cross-linking (HHIC) treatment. With the HHIC treatment, the polar functionalities of PAA (e.g., −COOH) can be preserved through selective cleavage of C–H bonds and subsequent cross-linking of resulting carbon radicals generated on PAA and PPXC chains. HHIC-treated PAA–PPXC film shows an excellent wetting stability, of which WCA and surface energy stay almost the same over 40 days. The improved wetting stability of PPXC film is attributed to the controllable HHIC reaction without undesirable side reaction (e.g., the scission of polymer chain backbone), which effectively restricts the rearrangement of PAA chains on the surface. Besides, the improved wetting stability by our approach results in reliable adhesion between silver ink and polymer films. Thus, fixing hydrophilic molecules on hydrophobic polymer surface by HHIC treatment could be an alternative approach to conventional surface treatments for preparation of stable wetting surface on polymer films.

Although superhydrophobic surfaces have various promising applications, their fabrication methods are often limited to 2D plane surfaces that are vulnerable to abrasion and have limited adhesion to the substrate. Herein, an ultraviolet (UV) curable ink with bulk superhydrophobicity, consisting of poly(dimethylsiloxane) (PDMS) resins, hydrophobic silica, and solvent (porogen), was successfully developed for UV-assisted direct write printing processing. After UV curing of the ink followed by solvent evaporation, the generated porous structure cooperates with silica particles to form a self-similar and hierarchical structure throughout the bulk material, which can keep its original morphology even after cyclic abrasion (over 1000 times) and thus exhibits durable superhydrophobicity. With this unique ink, UV-assisted direct write printing can not only create 2D superhydrophobic surfaces on various substrates (e.g., paper and wire mesh) but also fabricate self-supporting 3D superhydrophobic objects for various applications such as waterproofing and oil–water separation. The printed objects exhibited a stable superhydrophobicity against liquid corrosion and mechanical damage. In addition, the 3D printing approach can be used to optimize the oil–water separation performance of the superhydrophobic porous materials by tuning the pore size, thus presenting promising applications.

Abstract

3D printed elastomeric foams present good potential for mechanical application and their stress relaxation behaviors are critical for engineering performance. In this work, polydimethylsiloxane (PDMS) foams with simple tetragonal (ST) and face-centered tetragonal (FCT) structures were printed and present different stress relaxation behaviors. The ST foam had a similar stress relaxation rate to that of the stochastic foam (15–16%), whereas the FCT foam had a lower stress relaxation rate (10%). The ST foam had high local stress concentrations under compression, because it deformed by uniaxial buckling deformation, leading to high stress relaxation of the PDMS matrix. In contrast, the stress distribution was more uniform in the FCT foam due to its bending deformation under compression. Thus, the compressive deformation mechanism of the printed topology greatly affects the stress relaxation properties. This finding provides an important guide for the design of elastomeric foams with low stress relaxation for high performance applications.

A novel experimental technique to follow the crystallization processes of poly(propylene)/MWCNT composites that experience a steady shear deformation using dynamic melt rheometry is described. The effects of heterogeneous nucleation, temperature, and preshear on the crystallization behaviors were determined. A quantitative evaluation of crystallization kinetics difference between quiescent and preshear conditions could be achieved. By combining rheology with POM, we demonstrate that two different crystallization processes account for the shear‐enhanced crystallization at low and high temperatures, respectively.

Passive daytime radiative cooling (PDRC) involves cooling down an object by simultaneously reflecting sunlight and thermally radiating heat to the cold outer space through the Earth’s atmospheric window. However, for practical applications, current PDRC materials are facing unprecedented challenges such as complicated and expensive fabrication approaches and performance degradation arising from surface contamination. Herein, we develop scalable cellulose-fiber-based composites with excellent self-cleaning and self-cooling capabilities, through air-spraying ethanolic poly(tetrafluoroethylene) (PTFE) microparticle suspensions embedded partially within the microsized pores of the cellulose fiber to form a dual-layered structure with PTFE particles atop the paper. The formed superhydrophobic PTFE coating not only protects the cellulose-fiber-based paper from water wetting and dust contamination for real-life applications but also reinforces its solar reflectivity by sunlight backscattering. It results in a subambient cooling performance of 5 °C under a solar irradiance of 834 W/m2and a radiative cooling power of 104 W/m2under a solar intensity of 671 W/m2. The self-cleaning surface of composites maintains their good cooling performance for outdoor applications, and the recyclability of the composites extends their life span after one life cycle. Additionally, dyed cellulose-fiber-based paper can absorb appropriate visible wavelengths to display specific colors and effectively reflect near-infrared lights to reduce solar heating, which synchronously achieves effective radiative cooling and esthetic varieties.