Effect Of Micro Research Articles

Enhancement of biological effects of oxidised nano- and microplastics in human professional phagocytes

Micro and nanoplastics are ubiquitous pollutants that can cause adverse health effects even in humans. Effects of virgin and oxidised (simulating the aging processes) polystyrene nano (nPS) and micro particles (mPS) with diameters of 0.1 and 1 µm were studied on human professional phagocytes (i.e., monocyte cells THP-1 and macrophage-like mTHP-1 cells). After characterization by ATR-FTIR, UV-Vis spectroscopy, SEM and dynamic light-scattering analyses, the particles were FITC functionalised to quantify cellular uptake. Changes in the cell compartments were studied by acrydine orange and the pro-oxidant, cytotoxic and genotoxic effects were assessed. Phagocytosis was dose- and time- dependent and at 24 h 52% of nPS and 58% of mPS were engulfed. Despite the high homeostasis of professional phagocytes, significant ROS increases and DNA damage were observed after exposure to oxidised particles. The results highlight that the environmental aging processes enhances the adverse health effects of micro and nanoplastics.

An In Vitro Assay to Quantify Effects of Micro- and Nano-Plastics on Human Gene Transcription

In today’s age, plastic waste is a major problem for our environment. The decomposition of plastic waste causes widespread contamination in all types of ecosystems worldwide. Micro-plastics in the lower micrometer size range and especially nano-plastics can become internalized by cells and thus become a threat to human health. To investigate the effects of internalized micro- and nano-plastics on human gene transcription, we used an in vitro assay to quantify CREB (cAMP response element binding protein) mediated transcription. Here we show that CREB mediated gene expression was mainly but not exclusively induced by phosphorylation. In addition, the amount of CREB affected transcription was also studied. We were also able to show that the strong CREB mediated stimulation of transcription was diminished by micro- and nano-plastics in any chosen setting. This indicates a threat to human health via the deregulation of transcription induced by internalized micro- and nano-plastics. However, this established quantifiable in vitro transcription test system could help to screen for toxic substances and non-toxic alternatives.

Printing channels with millimeter-scale curvature and deciphering their effect on the proliferation, morphology, orientation, and migration of M-22 cells.

Complex curved structures of tissues have been recognized to influence the behavior and function of cells. Tissue curvatures sensed by cells are approximately on the millimeter scale. However, previous research mainly focused on the effect of micro- and nano-scale spatial curved structures, underestimating the significance of milli-scale curvature. Here, we employed fused deposition modeling (FDM) with two-stage temperature control, superfine cone-shaped needle, stable air pressure, and precise motion platform for the customized production of homogeneous, precise, and curved fibers; the responses of M-22 cells to FDM-printed curved channels with radii of 1.5 to 3 mm were systematically investigated. The cells aligned with these curved channels and exhibited various aspect ratios in the channels with different curvatures. Cell proliferation, migration speed of single cells, and front-end speed of collective cells were tightly regulated by these curved structures. Also, a computational model based on force equilibrium was proposed to explore the essential factors and mechanisms of curvature affecting cell behavior. Our simulation results demonstrated that the curvature and width of channels, along with the relative size of cells, can significantly impact the cell-boundary interaction force and the number of valid pseudopodia generated by cells in the process of cell migration. These results provide a comprehensive understanding of the effect of milli-scale curvature on the cells and underpin the design of scaffolds that can be produced easily with sophisticated micro- and nano-scale curved features to regulate cell behavior in tissue engineering.

Effects of micro- and nano-sized emulsions on physicochemical properties of emulsion–gelatin composite gels

In this study, we aimed to investigate the effects of emulsion droplet size on the physicochemical and rheological properties of emulsion–gelatin composite gels. Gelatin or lecithin solutions (1–4%) as emulsifiers were homogenized with canola oil using a high-speed and/or high-pressure homogenizer to obtain micro- and nano-sized emulsions. Gelatin (8%) was mixed with an equal amount of the prepared emulsion and subsequently cooled at 4 °C for cold-set gelation. Gel strength of the emulsion–gelatin composite gels was higher when the concentration of gelation was increased, regardless of the droplet size of the emulsion. In terms of droplet size, gel strength, G′, and water-holding capacity of emulsion–gelatin composite gels with nano-sized emulsions were significantly higher than those of gels with micro-sized emulsions, except for lecithin. Fourier-transform infrared and differential scanning calorimetry analyses of emulsion–gelatin composite gels revealed that the emulsion size had a significant effect on the physicochemical properties of the gels, except for lecithin. Conformationally, droplet size influenced the gel strength of the emulsion–gelatin composite gels owing to the high specific surface area of the nano-sized droplets, which formed a relatively high number of junctions of gelatin random coils during cold-set gelation.

Comparison of the Effectiveness of Micro- and Nanoparticles of Zero-Valent Iron in the Detoxification of Technogenic Polluted Soil

We studied the safety of sorbents based on zerovalent iron in the form of micro- and nanoparticles and their detoxifying activity in peat eutrophic soil (Eutric Histosol) polluted by emissions from a copper-nickel (Cu/Ni) plant (Kola Peninsula, Russia). Iron nanoparticles, as well as iron microparticles at a dose of 2%, turned out to be non-toxic according to the results of three standard bioassays based on the reactions of test organisms of different taxonomic affiliation. Toxicity was assessed by the change in the length of the roots of seedlings of plants Sinapis alba L. in uncontaminated peat, by the survival of Ceriodaphnia affinis Lilljeborg and the protozoan Parameciun caudatum Ehrenberg in water extracts of the samples. Fe-containing preparations significantly reduced the ecotoxicity of the soil due to the extremely high content of copper (6877 mg/kg) and nickel (2580 mg/kg). Differences in the remediating ability of the preparations were revealed. According to the results of soil phytotesting, iron nanoparticles significantly outperformed the detoxifying effect of microparticles (iron powder). When analyzing the water extract, the superiority of nanoparticles in reducing soil toxicity was not found. The dependence of the assessment of the detoxifying ability of zerovalent iron nanoparticles on soil properties and the plant species used in phytotesting is discussed.

Microstructure determined the gel properties of gelatin/dextran more than the macrophase separation

Hydrogels are important in foods. Although the hydrogel microstructure has been commonly reported, the effect of the microstructure before and after gelation on gel properties was rarely investigated. This work aims to explore the effects of micro- and macro-phase separation of type-A gelatin-dextran (GE A /DE) aqueous solutions on the rheological, texture, and hydration properties of GE A /DE hydrogels. Three types of phase separation microstructures at both pH 5.0 and 7.0, e.g., DE-in-GE A emulsion, bicontinuous microstructure, and GE A -in-DE emulsion, were designed by adding different DE concentrations. GE A /DE mixtures showed macro-stability at pH 5.0, but macroscopic phase separation at pH 7.0, in which the phase separation time increased with the increasing DE concentration. During cooling-gelation, microstructures of mixtures were almost unchanged at pH 5.0, but significantly changed at pH 7.0. Interestingly, the microstructure determined the gel properties of phase-separated gels more than the macrophase separation. Microstructures of continuous phase with the gelling ability, e.g., DE-in-GE A and bicontinuous phase, hardly changed the moduli ( G′ and G″ ) and hardness of GE A /DE mixed gels, while the microstructure of GE A -in-DE without the gelling ability for continuous phase greatly reduced the moduli and hardness. This might be due to the different GE A volume fractions in GE A /DE mixed gels with different microstructures, and the mixed gel strength decreased with decreasing GE A volume fractions. Water holding capacity and swelling ratio of GE A /DE mixed gels reduced with the increasing DE concentration. This work provides some new information on how microstructure and macro-stability affect the physical properties of mixed gels. Effect of microstructure of GE A /DE before and after gelation on G′ and G″ at pH 5.0 and 7.0. • Three microstructures were designed based on gelatin/dextran phase separation. • Microstructures of macro-stable gelatin/dextran at pH 5.0 unchanged after gelation. • Microstructure determined gel properties more than the macrophase separation. • GE A volume fraction in the mixed gel might explain the effect of microstructures. • The gel strength of gelatin/dextran decreased with decreasing GE A volume fraction.

The Effects of Titanium Dioxide Nanoparticles on Osteoblasts Mineralization: A Comparison between 2D and 3D Cell Culture Models.

Although several studies assess the biological effects of micro and titanium dioxide nanoparticles (TiO2 NPs), the literature shows controversial results regarding their effect on bone cell behavior. Studies on the effects of nanoparticles on mammalian cells on two-dimensional (2D) cell cultures display several disadvantages, such as changes in cell morphology, function, and metabolism and fewer cell-cell contacts. This highlights the need to explore the effects of TiO2 NPs in more complex 3D environments, to better mimic the bone microenvironment. This study aims to compare the differentiation and mineralized matrix production of human osteoblasts SAOS-2 in a monolayer or 3D models after exposure to different concentrations of TiO2 NPs. Nanoparticles were characterized, and their internalization and effects on the SAOS-2 monolayer and 3D spheroid cells were evaluated with morphological analysis. The mineralization of human osteoblasts upon exposure to TiO2 NPs was evaluated by alizarin red staining, demonstrating a dose-dependent increase in mineralized matrix in human primary osteoblasts and SAOS-2 both in the monolayer and 3D models. Furthermore, our results reveal that, after high exposure to TiO2 NPs, the dose-dependent increase in the bone mineralized matrix in the 3D cells model is higher than in the 2D culture, showing a promising model to test the effect on bone osteointegration.

A review of the endocrine disrupting effects of micro and nano plastic and their associated chemicals in mammals.

Over the years, the vaste expansion of plastic manufacturing has dramatically increased the environmental impact of microplastics [MPs] and nanoplastics [NPs], making them a threat to marine and terrestrial biota because they contain endocrine disrupting chemicals [EDCs] and other harmful compounds. MPs and NPs have deleteriouse impacts on mammalian endocrine components such as hypothalamus, pituitary, thyroid, adrenal, testes, and ovaries. MPs and NPs absorb and act as a transport medium for harmful chemicals such as bisphenols, phthalates, polybrominated diphenyl ether, polychlorinated biphenyl ether, organotin, perfluorinated compounds, dioxins, polycyclic aromatic hydrocarbons, organic contaminants, and heavy metals, which are commonly used as additives in plastic production. As the EDCs are not covalently bonded to plastics, they can easily leach into milk, water, and other liquids affecting the endocrine system of mammals upon exposure. The toxicity induced by MPs and NPs is size-dependent, as smaller particles have better absorption capacity and larger surface area, releasing more EDC and toxic chemicals. Various EDCs contained or carried by MPs and NPs share structural similarities with specific hormone receptors; hence they interfere with normal hormone receptors, altering the hormonal action of the endocrine glands. This review demonstrates size-dependent MPs' bioaccumulation, distribution, and translocation with potential hazards to the endocrine gland. We reviewed that MPs and NPs disrupt hypothalamic-pituitary axes, including the hypothalamic-pituitary-thyroid/adrenal/testicular/ovarian axis leading to oxidative stress, reproductive toxicity, neurotoxicity, cytotoxicity, developmental abnormalities, decreased sperm quality, and immunotoxicity. The direct consequences of MPs and NPs on the thyroid, testis, and ovaries are documented. Still, studies need to be carried out to identify the direct effects of MPs and NPs on the hypothalamus, pituitary, and adrenal glands.

Photonic Spin Hall Effect in Micro- and Nano-Optics

Photonic Spin Hall Effect in Micro- and Nano-Optics

CONTRIBITION OF MICRO-SILICA AND NANO-MONTMORILLONITE REINFORCEMENTS ON THE MECHANICAL PROPERTIES OF UV-CURABLE THERMOSET RESIN

UV-curable thermoset resins had been utilized in organic coating industry because of their benefits over conventional adhesives like fast curing, less energy consumption and equipment. In this article, the effects of micro and nano-scaled reinforcements on the mechanical properties of a UV-curable thermoset resin were investigated. The reinforcements are chosen to be nano-scaled Montmorillonite (MMT) and micro-scaled Silica (SiO2). The reason for this choice is that the aforementioned particles are non-toxic, low-cost and in the case of MMT; abundant in nature. According to our knowledge, there is no study on the synergistic effects of those two additives in thermoset resins. 
 The instrumented microindentation test results reveal that maximum improvement on hardness (288%) was achieved by single addition of MMT thanks to the well-distributed silicate layers. Conversely, SiO2 addition diminished both strength (-51%) and modulus (-68%) drastically which is attributed to the possible poor dispersion and weak surface attraction. On the other hand, when those additives were utilized together, the property improvements namely; hardness and modulus are observed to be in between of single addition of either additive. It is suggested that SiO2 contribution does not disturb intercalated/exfoliated-MMT structure and similarly by simultaneous MMT reinforcement, quality of SiO2 dispersion is not affected. It is concluded that one benefit of these SiO2-MMT combinations over single MMT reinforcement could be related to plasticity since they result in less plasticity reduction of -22%-27% compared to MMT (-43%) with the further benefit of higher hardness improvement (+66%) than bare SiO2 addition (-51%).

A comparative investigation of the sorption of polycyclic aromatic hydrocarbons to various polydisperse micro- and nanoplastics using a novel third-phase partition method

Evidence for direct adverse effects of micro- and nanoplastic particles (MNPs) on human health is scarce, but it has been hypothesized that MNPs act as carriers for environmental pollutants such as polycyclic aromatic hydrocarbons (PAHs). Many studies have already investigated the sorption of PAHs to microplastics, typically using the batch-equilibrium method. Here we established a novel third-phase partition (TPP) method utilizing thermo-extractable polydimethylsiloxane-coated stir-bars as re-usable passive samplers to compare the sorption of PAHs to 17 different MNPs. This method facilitates the quantification of MNP-sorbed pollutants, including those with poor water-solubility without requiring laborious filtration and solvent-extraction steps. Using benzo[a]pyrene (B[a]P) as a representative PAH, sorption kinetics and isotherms for MNPs were evaluated. B[a]P sorption was generally strong but differed by over two-orders of magnitude, clustering according to polymer types in the order of polyamides > polyethylenes ≫ Tire Rubber > polyurethanes > polymethyl methacrylate. B[a]P sorption was diminished for photo-aged MNPs. Within given polymer types, properties including particle size, polarity/hydrophobicity and chain mobility notably influenced B[a]P sorption. When comparing different PAHs, their sorption to selected MNPs increased over five-orders of magnitude with hydrophobicity: anthracene < B[a]P < dibenzo[a,l]pyrene. Our data is an important contribution to the understanding of the sorption behaviors of MNPs. The novel TPP-method represents a universally-applicable approach for the reliable evaluation of sorption characteristics of contaminants and MNPs, and can be easily adapted to desorption studies.Graphical

Pyrite-enhanced Sludge Digestion via Stimulation of Direct Interspecies Electron Transfer between Syntrophic Propionate- and Sulfur-oxidizing Bacteria and Methanogens: Genome-centric Metagenomics Evidence

The supplementation of conductive materials (CMs) is a promising strategy to improve the methane (CH4) yield from anaerobic digestion (AD) of sewage sludge. However, most CMs are relatively costly, and the mechanisms by which they influence microbial functional traits (e.g., direct interspecies electron transfer (DIET) and extracellular polymeric substances (EPS)) remain poorly understood, which limits the application of CMs for enhancing CH4 production. Here, we investigated the effects of micro- and milli-scale particles of pyrite (an iron-based (semi)conductive waste, supplemented at doses of 5–40 g/L) on sludge digestion, and the underlying mechanisms. The results indicated that CH4 production rate and yield were improved mostly (by 20.8 % and 37.8 %, respectively) by the addition of 5 g/L micro-scale pyrite. The hydrolysis, acidification, and acetoclastic methanogenesis steps were accordingly promoted by 17.0–98.2 %, and the corresponding activities of key enzymes were elevated by 27.2–33.4 %. Pyrite enriched the populations of Anaerolineae and Burkholderiales, which are putative EPS producers according to genome-centric metagenomics, thus boosting the secretion of redox-active components in EPS and facilitating extracellular electron transport. Interestingly, pyrite may mediate “dual-drive” DIET, in which bin 116 (Syntrophobacteraceae sp.) and bin 2 (Thiobacillaceae sp.) directly transfer the electrons released by the oxidation of propionate and sulfide, respectively, to methanogen bin 28 (Methanothrix soehngenii). These results provide deep insights into the highly favorable performance of pyrite-supplemented AD systems and the microbial mechanisms. The proposed pyrite-mediated dual-drive DIET could expand the diversity of electron-donating bacteria and provide a novel microbial strategy for the simultaneous recovery of CH4 and elemental sulfur from waste organic streams in CM-supplemented AD systems.

THE EFFECT OF MICRO, SMALL AND MEDIUM ENTERPRISES, CAPITAL EXPENDITURE, INVESTMENT, AND LABOR ON INDONESIA'S ECONOMIC GROWTH

This study aims to analyse the effect of micro, small, and medium enterprises (MSMEs), capital expenditure, investment, and labour on Indonesia's economic growth. This research adopts a quantitative methodology and bases its findings on secondary data obtained from the Central Statistics Agency. The analysis included 330 samples from 33 provinces, all chosen using the purposive sampling method. The total number of observations in the study was 33. According to the panel data analysis, findings carry out with the aid of the programme processing tools found in E-Views 9.0. The results of this study show that capital expenditure, investment, and labour partially have a significant positive effect on Indonesian economic growth. On the other hand, variable MSMEs have no impact on the economic development of Indonesia. Another finding from the analysis is that the estimated regression model can explain Indonesia's economic growth

Effect of Micro- and Nano-Lignin on the Thermal, Mechanical, and Antioxidant Properties of Biobased PLA-Lignin Composite Films.

Bio-based poly(lactic acid) (PLA) composite films were produced using unmodified soda micro- or nano-lignin as a green filler at four different contents, between 0.5 wt% and 5 wt%. The PLA-lignin composite polymers were synthesized by solvent casting to prepare a masterbatch, followed by melt mixing. The composites were then converted into films, to evaluate the effect of lignin content and size on their physicochemical and mechanical properties. Differential scanning calorimetry (DSC), supported by polarized light microscopy (PLM), infrared spectroscopy (FTIR-ATR), X-ray diffraction (XRD), and transmission electron microscopy (TEM) were employed to investigate the PLA crystallization and the interactions with Lignin (L) and Nanolignin (NL). The presence of both fillers (L and NL) had a negligible effect on the glass transition temperature (chain diffusion). However, it resulted in suppression of the corresponding change in heat capacity. This was indicative of a partial immobilization of the PLA chains on the lignin entities, due to interfacial interactions, which was slightly stronger in the case of NL. Lignin was also found to facilitate crystallization, in terms of nucleation; whereas, this was not clear in the crystalline fraction. The addition of L and NL led to systematically larger crystallites compared with neat PLA, which, combined with the higher melting temperature, provided indications of a denser crystal structure in the composites. The mechanical, optical, antioxidant, and surface properties of the composite films were also investigated. The tensile strength and Young's modulus were improved by the addition of L and especially NL. The UV-blocking and antioxidant properties of the composite films were also enhanced, especially at higher filler contents. Importantly, the PLA-NL composite films constantly outperformed their PLA-L counterparts, due to the finer dispersion of NL in the PLA matrix, as verified by the TEM micrographs. These results suggest that bio-based and biodegradable PLA films filled with L, and particularly NL, can be employed as competitive and green alternatives in the food packaging industry.

Environmental Contamination with Micro- and Nanoplastics Changes the Phototaxis of Euryhaline Zooplankton to Paired Photostimulation

Our earlier studies showed that paired photostimulation allows the detection of pollutants in an aqueous medium according to the behavioral responses of freshwater Crustacea. The first stimulus initiated and stabilized the behavioral response. The increase in response to the second stimulus made it possible to assess the responsiveness of the zooplankton community. This paper studies the validity of this method for the detection of micro- and nanoplastic contamination of saltwater reservoirs according to the behavioral response of Artemia salina and Moina salina crustaceans. The studies were conducted in laboratory conditions using a submersible holographic camera developed by us, which ensures the in situ detection of the concentration and speed of crustaceans in a volume of up to 1 dm3, as well as makes it possible to change the intensity and duration of the attracting light. It was established that the phototropic response of crustaceans decreases in seawater at the cumulative dose of exposure to microplastics—0.15 mg∙dm−3∙h and nanoplastics—0.3 mg∙dm−3∙h. The paired photostimulation reveals the altering effect of micro- and nanoplastics in the saltwater medium no later than 3 h after their appearance, which indicates the promising potential of this method for the alarm response in monitoring the environmental well-being of water bodies.

Effect of micro–spray on plant growth and chlorophyll fluorescence parameter of tomato under high temperature condition in a greenhouse

Micro–spray is usually used to improve plant growth environment to avoid growth inhibiting and yield decreasing due to the high temperature inside the greenhouses in summer. To investigate the effect of micro–spray on plant growth and physiological properties, a combined irrigation method of micro–spray and drip irrigation (MSDI) was applied to tomato plants growing in a Venlo–type greenhouse for two seasons. The plant growth and physiological parameters of tomatoes grown under MSDI were compared with them under drip irrigation (DI). The running time of micro–spray was set based on the timing of high air temperature (Ta) appeared. The micro–spray was opened (7.5 L/h for each nozzle) for 1 min for each time point at 9:00, 10:00, 11:00, 12:00, 13:00 and 14:00 when the Ta was higher than 30 °C. The MSDI had a positive effect on plants growth (18% increased in stem diameter compared to DI) and the leaf temperature (Tl) decreased around 3–6 °C when the micro–spray was operated, and the cooling effect can be sustained for 10–30 min. Water use efficiency (WUE) under MSDI was similar to it under DI by comparing yield and total water consumption of tomato plants, and the total soluble solids (TSS) of tomato under two irrigation methods were similar (5.4% under DI and 5.5% under MSDI) during 2021.The results shown that the photosynthetically active radiation (PAR) and Ta were represented a negative correlation with chlorophyll fluorescence parameter (the effective quantum yield of PSII, ФPSII). The ФPSII value of tomato under MSDI was higher than it under DI during the micro–spray operating period, and it was more stable during the high Ta period. The improvement rate of ФPSII at different intensity of PAR (at 9:30, 10:30, 11:30, 12:30, 13:30 and 14:30) was varied, and it had a unified decline at 12:30 at the highest Tl during two seasons. Short time (1minute) micro–spray application did not have a remarkable effect on the adjusting of the damage caused by heat stress once temperature over 35 °C. Applying MSDI for tomato plants grown in greenhouse is recommended to reduce the severe effect on plant growth and physiology by high temperature. In addition, the result of this study provides a scientific guide for the development of intellectualization irrigation systems.

Analytical methodologies used for screening micro(nano)plastics in (eco)toxicity tests

Micro(nano)plastics accumulate in natural environments worldwide, threatening biota, ecosystem functions, and services. In the last decade, there has been a substantial increase in the number of ecotoxicity studies to address the potential effects of micro(nano)plastics, including their plasticisers and adsorbed hazardous substances. Their environmental relevance has been under scrutiny due to the non-environmentally relevant testing conditions besides the lack of a proper characterization of the particles under study (e.g., size range, surface properties, crystallinity, chemical composition, including additives compounds), thus compromising the significance of the risk assessment and management strategies. This paper reviews the analytical methodologies applied in ecotoxicity tests for identifying, quantifying, and eventual characterising micro(nano)plastics before, during (monitoring), and after exposure, addressing their advantages and limitations. It also discusses emerging and cost-efficient methodologies that may speed up the detection and quantification of micro(nano)plastics and motivate their characterization for a deeper understanding of the underlying (eco)toxicity mechanisms.

Effect of Oxide Flux Particle Size on Weld Bead Morphology of Hastelloy C-22

Activated tungsten inert gas welding (ATIG) welding is a new approach to Tungsten Inert Gas (TIG) welding that has the potential to improve weld penetration. This paper investigates the effect of micro and nanoparticle size oxide flux during TIG welding of Hastelloy C-22. The effect of SiO&lt;sub&gt;2&lt;/sub&gt; and Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; oxide fluxes in terms of particle size and thermal stability on surface appearance, bead geometry, and microhardness of the fusion zone of hastelloy C-22 is investigated. The surface appearance of ATIG weld has a better appearance using nanoparticle size oxide flux when compared with the same micro size oxide flux. A slag layer produced by nano flux decomposition during TIG welding is very less compared to micro oxide fluxes. Nanoparticle SiO&lt;sub&gt;2&lt;/sub&gt; flux has the potential to improve weld penetration and depth to width (D/W) ratio in the generated weldment when compared to microparticle SiO&lt;sub&gt;2&lt;/sub&gt; flux during TIG welding Process. When nanoparticle Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; is used in TIG welding, weld penetration or the D/W ratio do not increase significantly. Due to the high voltage produced at the same arc length, TIG welding with nanoparticle SiO&lt;sub&gt;2&lt;/sub&gt; flux produces a high heat input. Furthermore, higher arc temperatures produce by nanoparticle fluxes at the arc column, resulting in increased penetration depth.

Synergistic effect of micro–nano surface structure and surface grafting on the efficient fabrication of durable super-hydrophobic high-density polyethylene with self-cleaning and anti-icing properties

An industrialized polymer molding technology that combines water-soluble etching and surface chemical reactions was proposed for preparing a superhydrophobic high-density polyethylene (H@G-E/HDPE) sheet. HDPE sheets were etched with a saturated aqueous solution of NaF to create a rough surface, after which glycidyl methacrylate (GMA) was introduced onto the HDPE surface to create a large number of reactive sites on the inert surface of HDPE, enabling further grafting of a low-surface-energy hydroxyl-terminated fluorosilicone oil (HTFO) onto the HDPE surface. The H@G-E/HDPE sheet exhibited high hydrophobicity, with a water contact angle (WCA) of 158 ± 1° and sliding hysteresis angle (SHA) of 8 ± 1°. The sheet also exhibited good durability, with a WCA greater than 150° after 240 h of strong stirring in water or abrasion with sandpaper for 120 rubs. The H@G-E/HDPE sheet exhibited chemical resistance and maintained super-hydrophobicity even after 24 h of immersion in a strong acid/alkali solution. Furthermore, the super-hydrophobicity of the as-obtained H@G-E/HDPE sheet was maintained upon impact with water droplets at 0.77 m/s, along with low ice adhesion at 11.64 ± 1.74 KPa, a significantly longer icing delay time, and self-cleaning properties. The developed superhydrophobic H@G-E/HDPE sheet featuring low-cost and efficient fabrication has promising applications in many industries, such as pipelines, membranes, packaging, and electronic equipment.

Design and fabrication of micro and nano surface structures for enhancing metal–polymer adhesion using femtosecond laser treatment

This study investigated the effects of micro- and nanostructures on the adhesion strength between copper and an encapsulating mold compound (EMC). The shape of the microgrooves was designed based on fracture mechanics theory, and the effect of laser-induced periodic structure surface (LIPSS) formation on the microgroove was investigated using numerical simulations. The designed surface profiles were fabricated using femtosecond laser treatments, and the adhesion strength between copper and the EMC was evaluated. The results show that deep microgrooves improved the adhesion strength owing to the anchor effect. However, the aspect ratio between the pitch and depth of the microgroove had a limitation in enhancing the adhesion strength. The formation of LIPSSs on the mountaintop of the microgroove was very effective; however, an LIPSS on the valley of the microgroove was ineffective. Numerical analyses revealed that LIPSSs suppressed the shear deformation of the EMC and worked as resistance to interface delamination. Based on the findings obtained in this study, combining micro- and nano-scale surface structure formation with femtosecond laser treatments is an effective and eco-friendly method for improving adhesion strength.