Polystyrene Nanospheres Research Articles

Evaluation of antioxidant capacity and digestive enzyme activities in Mytilus galloprovincialis exposed to nanoplastics under different patterns of hypoxia

In the marine environment, plastic pollution may occur simultaneously with hypoxia. However, current ecological risk assessments of nanoplastics have rarely considered the impact of additional environmental factors, such as hypoxia. In this study, we investigated the effect of polystyrene nanospheres (PS-NPs) on the digestive performance (antioxidant system and digestive enzymes) of mussels Mytilus galloprovincialis under different patterns of hypoxia (normoxia, constant hypoxia, and fluctuating hypoxia). The result showed that PS-NPs caused oxidative damage in the digestive glands of mussels, while all patterns of hypoxia exacerbated this oxidative damage. Activities of four digestive enzymes (α-amylase, cellulase, trypsin, and lipase) were examined. Among these, the activity of the α-amylase was inhibited by PS-NPs, and the inhibition was aggravated by all the hypoxia patterns. The cellulase activity and trypsin activity was enhanced by PS-NPs, and the increase was further stimulated by hypoxia. Lipase activity was not affected by PS-NPs alone, but significant inhibition was detected after the coexposure to PS-NPs and hypoxia. Conclusively, the combined stress of hypoxia and nanoplastics can significantly affect the digestive performance of mussels and may alter the mussel nutrient uptake strategy. Our work has provided new insight into the ecological risk assessment of plastics under global climate change.

Tunable Antireflection Properties with Self-Assembled Nanopillar and Nanohole Structure.

Nanostructure engineering has proven to be one of the most effective strategies to improve the efficiency of photoelectric devices. Herein, we numerically investigate and experimentally demonstrate a self-assembled silicon-based nanopillars and nanoholes structures, to improve the light absorption of photoelectric devices by an antireflection enhancement. The nanopillars and nanoholes structures are fabricated by the air-liquid interface self-assembly method based on polystyrene (PS) nanospheres. Additionally, the tunable antireflective properties with the different operation wavelength and nanostructures parameters have been discussed based on the Finite-Difference Time-Domain (FDTD) method. The experimental result shows that the self-assembled silicon-based nanopillars and nanoholes structures can achieve the lowest reflectivity of 1.42% (nanopillars) and 5.83% (nanoholes) in the wavelength range of 250-800 nm, which reduced 95.97% and 84.83%, respectively, compared with the plane silicon. The operation mechanism of the tunable antireflective property of self-assembled nanopillars and nanoholes structures is also analyzed in the simulation. Our study suggests that the self-assembled nanopillars and nanoholes structures are potentially attractive as improving efficiency of photoelectric devices.

Nanosphere Lithography-Based Fabrication of Spherical Nanostructures and Verification of Their Hexagonal Symmetries by Image Analysis

Nanosphere lithography (NSL) is a cost- and time-effective technique for the fabrication of well-ordered large-area arrays of nanostructures. This paper reviews technological challenges in NSL mask preparation, its modification, and quality control. Spin coating with various process parameters (substrate wettability, solution properties, spin coating operating parameters) are discussed to create a uniform monolayer from monodisperse polystyrene (PS) nanospheres with a diameter of 0.2–1.5 μm. Scanning electron microscopy images show that the PS nanospheres are ordered into a hexagonal close-packed monolayer. Verification of sphere ordering and symmetry is obtained using our open-source software HEXI, which can recognize and detect circles, and distinguish between hexagonal ordering and defect configurations. The created template is used to obtain a wide variety of tailor-made periodic structures by applying additional treatments, such as plasma etching (isotropic and anisotropic), deposition, evaporation, and lift-off. The prepared highly ordered nanopatterned arrays (from circular, triangular, pillar-shaped structures) are applicable in many different fields (plasmonics, photonics, sensorics, biomimetic surfaces, life science, etc.).

Granular limestone amended sand filters for enhanced removal of nanoplastics from water: Performance and mechanisms

Effluent from wastewater treatment plants (WWTPs) has been regarded as one of the major contributors of nanoplastics (NPs) in the environment. Improving the performance of rapid sand filter (RSF) systems in WWTPs is thus in urgent need. In this study, granular limestone, a low-cost and abundant natural material, was integrated into RSF systems to enhance NP removal from water. Laboratory filtration columns packed with pure sand and limestone-amended sand were applied to remove polystyrene nanospheres (100 nm) from deionized water (DIW) and artificial wastewater (AWW) under different grain size and flow velocity conditions. Pure sand filter showed neglectable NP removal from DIW but much higher NP removal from AWW, especially when fine sand was employed. Limestone amended RSF had a significant improvement in the removal of NPs for all the tested conditions and the removal efficiency of NPs became greater with increasing amount of limestone in columns. The sensitivity of NP immobilization to flow velocity changed significantly with different combinations of filter and background solutions. Coupled effects of physical straining, electrostatic interaction, cation screening and bridging, and surface roughness controlled the retention behaviors of NPs in the columns. The higher removal efficiency of NPs by limestone can be mainly attributed to its chemical composition as well as its surface heterogeneity and roughness. Results of this study demonstrate that limestone can offer extensive application potential for enhancing the performance of RSF systems in WWTPs to remove NPs from wastewater.

Universal one-pot strategy for fabricating supported chiral organocatalysts via direct covalent immobilization upon hollow mesoporous polystyrene nanospheres

Heterogeneous asymmetric organocatalysis is severely limited by two problems: mult-step energy- and time-consuming covalent immobilization of expensive organocatalysts and difficulty in controlling the morphology and porous structure of supported organocatalysts. Herein, a universal strategy is presented for the direct covalent immobilization of structurally different chiral organocatalysts upon hollow mesoporous organic polystyrene nanospheres (HMOPNs) via a one-pot tandem reaction. Owing to the steric confinement and fast mass transfer originating from their hollow interior, thin shell thickness and abundant mesopores, these supported chiral organocatalysts show excellent catalytic performances in the stereo-controlled steps of the synthesis of natural products and pharmaceuticals in good to high yields (76–96%) with excellent enantioselectivities (93–99% ee). This one-pot immobiliza- tion strategy paves a universal way for direct covalent immobilization of chiral organocatalysts bearing phenyl/aryl moiety to fabricate supported chiral organocatalysts with good long-term performances, achieving the low-cost production of chiral molecules.

Curvature modulated structural and magnetic properties of CoO/Co thin films deposited onto 2-D nanosphere array

The importance and applications of nanoscale magnetic storage devices has been of current interest owing to the extensive research interest in magnetic nanocaps. Continuing their research trend, we have attempted to synthesize and characterize an important isolated magnetic nanocaps system constituting Co and its oxide. CoO/Co thin films were deposited onto self-assembled arrays of polystyrene (PS) nanospheres (∼600 nm diameter) under ultra-high vacuum environment using electron beam evaporation technique. The magnetic and structural properties of these nanostructures were then compared with those of simultaneously deposited films on bare Si substrate (referred to as reference film). The studied film and the reference film were grown in polycrystalline manner as observed from X-ray diffraction measurements while their roughnesses as observed from X- ray reflectivity were quite different. X- ray reflectivity showed that for the reference films well defined Kiessig oscillations appeared suggesting low roughness in the deposited films, while the films on PS followed the curvature of underlying nanospheres and thus have very high roughness resulting in the disappearance of Kiessig oscillations. Magnetic measurements exhibited a drastically high coercivity when the substrate was changed from flat (Si) to curved one (PS). As the film thickness was increased, the coercivity first showed a slight decrement (4.92 kA/m) and beyond 40 nm film thickness, it showed some enhancement (14.2 kA/m). The exchange bias measurements also showed interesting results with variation in film thickness. Co 10 nm film deposited on PS showed negative exchange bias of −127 kA/m which decreased to −26 kA/m in 100 nm film. The overall results were explained by correlating the magnetic and microstructural properties of the thin films as a function of thickness.

A High-Performance Self-Supporting Electrochemical Biosensor to Detect Aflatoxin B1.

High-performance electrochemical biosensors for the rapid detection of aflatoxin B1 (AFB1) are urgently required in the food industry. Herein, a multi-scaled electrochemical biosensor was fabricated by assembling carboxylated polystyrene nanospheres, an aptamer and horseradish peroxidase into a free-standing carbon nanofiber/carbon felt support. The resulting electrochemical biosensor possessed an exceptional performance, owing to the unique structures as well as the synergistic effects of the components. The 3D porous carbon nanofiber/carbon felt support served as an ideal substrate, owing to the excellent conductivity and facile diffusion of the reactants. The integration of carboxylated polystyrene nanospheres with horseradish peroxidase was employed as a signal amplification probe to enhance the electrochemical responses via catalyzing the decomposition of hydrogen peroxide. With the aid of the aptamer, the prepared sensors could quantitatively detect AFB1 in wine and soy sauce samples via differential pulse voltammetry. The recovery rates of AFB1 in the samples were between 87.53% and 106.71%. The limit of detection of the biosensors was 0.016 pg mL−1. The electrochemical biosensors also had excellent sensitivity, reproducibility, specificity and stability. The synthetic strategy reported in this work could pave a new route to fabricate high-performance electrochemical biosensors for the detection of mycotoxins.

Fabrication and Surface Modification of Macroporous Silica Fibers by Electrospinning for Super Adsorbent of Oil

Silica fibers were fabricated by sol-gel reaction and an electrospinning process. A high voltage source of electricity was applied to the prepared spinning solution to form the fibers. Macroporous silica fibers were prepared using polystyrene (PS) nanospheres as templates after calcination. The pore size could be controlled by adjusting the diameter of the PS nanospheres in the spinning solution. PS nanospheres with different diameters (250, 430, 600, 870, and 1000 nm) were synthesized for this purpose using the dispersion polymerization method. Silica fibers have a hydrophilic surface. A coating film applied to the fibers showed superhydrophilicity, which is not suitable for adsorbing oil contaminant. Thus, silane coupling agents containing methyl groups were used to modify the surface of the porous fibers to obtain hydrophobic and water-repellent properties. The amount of oil adsorbed by the porous silica fibers modified with various kinds of coupling agent or PS nanospheres with different sizes was investigated, to determine their effects on oil adsorption. When the size of the macropores in the fibers increased, the amount of oil adsorption increased, because oil infiltration through the pores became easier. Small hydrophobic groups of the silane coupling agent, like methyl groups, were able to adsorb more oil compared to bulky functional groups. The measured oil adsorption capacity of the porous fibers was found to be larger than that of mesomacroporous silica particles, since the voids between the fibers might provide additional space for oil adsorption.

Structural properties of ordered porous SnO2 nanostructure

Three-dimensional porous ordered SnO2 nanostructures have been fabricated by templating a sol–gel pre- cursor solution against the polystyrene nanospheres for the first time. Field emission scanning electron micrography (FESEM) indicates that the surface of the nanostructures is highly regular and the porous structures are perfectly ordered. Besides a broad emission band at 600 nm, the porous SnO2 nanostructures show an additional emission band at 430 nm, which is seldom seen in the bulk SnO2 materials. Spectral examinations and analyses reveal that the 430 nm band is induced by the interfacial effects between the porous frameworks.

Ultra-sensitive electrochemiluminescence biosensor for abrin detection based on dual-labeled phage display affibodies and polystyrene nanospheres

Abrin is a plant cytotoxin that poses a high threat to public safety and therefore requires highly sensitive and efficient detection methods. Affibodymolecules are artificial affinity proteins that have been widely studied in bioimaging and medical treatment but rarely used in bioassays. In this work, an electrochemiluminescence (ECL) biosensor for abrin was established with biotin and Ru(bpy)32+ dual-labeled phage display affibodies as molecular recognition and signal element. On this basis, dual-labeled polystyrene nanospheres (nano-PSs) were chosen to link with phages and further achieve ultra-sensitive detection. This assay has a triple signal amplification. First, capsid proteins of M13 phages have connected numerous signal molecules. Second, the nano-PSs bound to the surface of the phages also contained quite a few signal molecules. Third, with the theoretically infinitely repeatable “biotin - streptavidin (SA) - biotin” composite unit as the “mortise and tenon structure”, the dual-labeled nano-PSs further formed highly stacked nano-aggregates, ultimately achieving significant signal amplification. Besides, the detection platform of this assay is a portable electrochemiluminescence sensor based on the screen-printed electrode, which is small and easy to operate. Limit of detection (LOD) for abrin of the ECL biosensor was 9.3 fg/mL and the linear detection range was observed from 10 fg/mL to 100 pg/mL. This new biosensing system has also demonstrated good reproducibility, specificity, practicability and has great potential for highly sensitive detection of contaminants, toxins and biomarkers in environmental monitoring and clinical application.

A Novel Fabrication of Single Electron Transistor from Patterned Gold Nanoparticle Array Template-Prepared by Polystyrene Nanospheres.

In this paper, polystyrene microspheres were firstly prepared by seeded emulsion polymerization, and the uniform monolayer of polystyrene microspheres was prepared on the substrate by the dipping method. Then, polystyrene monolayer film was used as a mask and a low dimensional array structure of gold was prepared by bottom-up self-assembly process. After that, the method of solution etching and annealing was used, and the gold nanoparticle array was post-processed. As a result, gold nanoparticles were recrystallized, with an average diameter of about 50 nm. Subsequently, the semiconductor process was adopted, with focused ion beams induced deposition and electron beam evaporation, and single electron transistors were fabricated, based on self-assembled gold nanoparticles. Finally, the devices were fixed in a liquid helium cryostat and Coulomb blockade was observed at 320 mK. It is a novel fabrication of a single electron transistor based on gold nanoparticle array template and prepared with polystyrene nanospheres.

Early enteric and hepatic responses to ingestion of polystyrene nanospheres from water in C57BL/6 mice

Drinking water is one of numerous sources of human exposure to microscale and nanoscale plastic particles. Here, using a mouse model, we tested enteric and hepatic cellular responses to nanoplastic ingestion. At 1.5 or 25.5 h after an oral dose of 70 mg polystyrene nanospheres (PSNS)/kg (nominal diameters of 20 and 200 nm) in aqueous suspension female mice exhibit no overt signs of toxicity. Routine histopathology on small intestine and liver reveals no acute toxicity. Immunohistochemistry detects an increase in the number of enterocytes with cleaved caspase-3 (active form) after PSNS exposure (p ≤ 0.05) indicating progression toward lytic cell death via a proinflammatory pathway. This is not evident in liver after PSNS exposure. Transmission electron microscopy detects lytic cell death in enterocytes at 25.5 h after 200 nm PSNS exposure. Putative endosomes in liver appear to sequester 20 and 200 nm particles 25.5 h after exposure. Both 20 and 200 nm PSNS appear in putative perinuclear autolysosomes 25.5 h after treatment. No significant changes in gene expression in the small intestine or liver 25.5 h were observed after dosing, but there was a trend toward altered expression of cyp1b1 in the liver. Analysis of the fecal microbiome shows loss of diversity after exposure to both 20 and 200 nm particles after 25.5 h. Taken together, these results suggest risk from ingestion of nanoscale plastic particles from drinking water, which deserves systematic investigation.

Ecotoxicity of Heteroaggregates of Polystyrene Nanospheres in Chironomidae and Amphibian.

Due to their various properties as polymeric materials, plastics have been produced, used and ultimately discharged into the environment. Although some studies have shown their negative impacts on the marine environment, the effects of plastics on freshwater organisms are still poorly studied, while they could be widely in contact with this pollution. The current work aimed to better elucidate the impact and the toxicity mechanisms of two kinds of commercial functionalized nanoplastics, i.e., carboxylated polystyrene microspheres of, respectively, 350 and 50 nm (PS350 and PS50), and heteroaggregated PS50 with humic acid with an apparent size of 350 nm (PSHA), all used at environmental concentrations (0.1 to 100 µg L−1). For this purpose, two relevant biological and aquatic models—amphibian larvae, Xenopus laevis, and dipters, Chironomus riparius—were used under normalized exposure conditions. The acute, chronic, and genetic toxicity parameters were examined and discussed with regard to the fundamental characterization in media exposures and, especially, the aggregation state of the nanoplastics. The size of PS350 and PSHA remained similar in the Xenopus and Chironomus exposure media. Inversely, PS50 aggregated in both exposition media and finally appeared to be micrometric during the exposition tests. Interestingly, this work highlighted that PS350 has no significant effect on the tested species, while PS50 is the most prone to alter the growth of Xenopus but not of Chironomus. Finally, PSHA induced a significant genotoxicity in Xenopus.

Multiplexed surface-enhanced Raman scattering detection of melamine and dicyandiamide in dairy food enabled by three-dimensional polystyrene@silver@graphene oxide hybrid substrate

Owing to its ultranarrow spectral line width, surface-enhanced Raman scattering (SERS) as a specific fingerprint identification technology has exhibited its distinctive talent in the multiplexed assay of illegal food additives. Herein, a three-dimensional (3D) hybrid SERS substrate was constructed by utilizing polystyrene (PS) nanospheres as template matrix, silver as active interlayer, and graphene oxide (GO) as coating surface to enable the effective monitoring of mixed melamine and dicyandiamide in dairy food without interference. Through amalgamating the significant electromagnetic effect triggered by the PS-mediated 3D architectures with the chemical enhancement and molecule-enrichment abilities of GO, the proposed substrate exhibited a highly sensitive detection characteristics with reliable reproducibility, facilitating a limit of detection low to 2.8 × 10−8 M for 2-naphthalenethiol. After the further establishment of standard calibration lines, the feasibility of the proposed sensitive substrate in the multivariate monitoring of melamine and dicyandiamide was verified in milk as well as yogurt, achieving moderate recovery rates higher than 75%. This work proposed a facile strategy to construct 3D hybrid SERS substrate, which might show great promise to secure food security.

Fabrication of ionic liquid-functionalized polystyrene nanospheres via subsurface-initiated atom transfer radical polymerization for anti-fouling application

The chemical and biological characteristics of ionic liquids (IL) can be engineered via a suitable selection of their constituent anions and cations, which is instrumental in the research and the development of anti-biofouling materials. The ring-opening reaction and subsurface-initiated atom transfer radical polymerization (sSI-ATRP) were employed to prepare IL-functionalized polystyrene nanospheres effectively. The sSI-ATRP was used to graft the poly(glycidyl methacrylate) (PGMA) brushes onto crosslinked polystyrene (CPS) nanospheres while they were fully swollen. Subsequently, the imidazolium-based IL was bound onto PGMA brushes through ring-opening reaction between the epoxide groups of PGMA and the amine groups of IL. Furthermore, their anti-wear, antibacterial, and antifouling properties were comprehensively evaluated. Experimental results reveal that the as-prepared IL-functionalized PS nanospheres exhibited good antibacterial properties against both E. coli and S. aureus, attributable to the imidazole groups of IL, in addition to resisting adhesion of Porphyridium and Dunaliella. Moreover, the IL-functionalized CPS nanospheres manifested satisfactory wear resistance as against the traditional surface-initiated atom transfer radical polymerization (SI-ATRP), because the PGMA can graft on the surface and subsurface of the polystyrene nanospheres via sSI-ATRP. The as-obtained IL-functionalized polystyrene nanospheres can be mixed effectively with the self-polishing resin to acquire a novel self-polishing nanocomposite coating, the nanocomposite coating exhibit good antibacterial characteristics against E. coli and S. aureus, as well as a substantial antifouling effect against microalgae (83 % Porphyridium and 85 % Dunaliella were removed).

Aqueous aggregation and deposition kinetics of fresh and carboxyl-modified nanoplastics in the presence of divalent heavy metals

The presence of heavy metals alters the colloidal stability and deposition of nanoplastics (NPs) in urban waters. Such processes are important to assess the mobility and fate of NPs and their associated heavy metals. Up to date, few studies have reported the impact of heavy metals on the colloidal behaviors of NPs and the involved mechanisms. In the study, time-resolved dynamic light scattering (DLS) and quartz crystal microbalance with dissipation (QCM-D) methods were used to assess the aggregation and deposition kinetics of polystyrene nanospheres with divalent heavy metals. For comparison, carboxyl-modified polystyrene nanospheres were used. Results reveal that heavy metals destabilized NPs more significantly than calcium ions. Spectroscopy and transmission electron microscopy analysis propose that heavy metals destabilized NPs via inner-sphere coordination with carboxyl groups and cation-π interactions, further leading to the formation of different dimensional aggregates. QCM-D results suggest that the deposition rate, irreversibility, and film compactness of NPs on silica surfaces first increased but further decreased as heavy metal concentration increased. Such deposition behaviors depended on the bridging effects between NPs and silica and aggregation-induced diffusion limitation. In that case, the destabilization and retention ability of heavy metals for NPs were related to their electronegativity and hydration shell thickness. In urban waters, the presence of natural organic matter (NOM) decreased the destabilization and retention ability of heavy metals, whereas heavy metals with environmentally relevant concentrations still enhanced the aggregation and deposition of NPs compared with other environmental cations. This study highlights the impact of heavy metal property on the colloidal behaviors of NPs, thus deepening our understanding of the mobility and fate of NPs associated with heavy metals in urban waters.

Bioinspired Microplate Arrays for Magnetically Tuned Dynamic Color

AbstractFast responding and remote controllable dynamic color is critical in many fields such as image display, senors, and camouflage. In this work, inspired by the structural color of hummingbirds, magnetic‐field driven polymer microplate arrays with dynamic iridescence are demonstrated. The microplates are coated with a layer of photonic crystal (PC) assembled by monodispersed polystyrene nanospheres. The structural color of PC is angle‐dependent, which can be dynamically switched by tuning the tilting angle of the microplates. Magnetic field manipulation is achieved by incorporating ferromagnetic NbFeB powder into the polymer film. Pattern display is also demonstrated by pre‐programing the tilting angle of microplates. This strategy enables fast remote control of high‐resolution structural color. It merits potential applications in many fields such as iridescent mark and invisible patterns for anti‐counterfeiting.

P-257 Nanosphere-based assessment of zona pellucida permeability in humans and mammalian models

Abstract Study question What is the maximum particle size that can traverse through human zona pellucida (ZP) and that of other mammals? Summary answer Human oocytes ZP is impermeable to 40-100 nm nanospheres. ZP of other mammals is impermeable to 100 nm particles, and permeability changes along preimplantation development. What is known already ZP is a porous structure that protects oocytes and early embryos, being permeable to nourishing and signaling substances while blocking the entrance of immune cells and viruses into the perivitelline space. Size-dependent ZP permeability is poorly known and may differ between species, as in humans and rabbits ZP it is composed by 4 proteins (ZP1-4), while bovine and murine ZPs contain only 3 proteins (ZP2-4 in bovine, ZP1-3 in mice). Understanding permeability is crucial to determine embryo susceptibility to viral infections or large biological particles such as exosomes, and to assess possible damages inferred by artificial reproductive techniques. Study design, size, duration The objective has been to determine ZP permeability in mice, bovine, rabbit (wild-type or lacking ZP4) or human oocytes and/or embryos based on particle size. The assay was performed in 3 replicates of 3 samples per stage: mouse samples (oocytes, zygotes, 2-cell embryos and blastocysts) collected in vivo, bovine samples (oocytes, zygotes, 4-8 cell embryos and blastocysts) produced in vitro, rabbit samples (zygotes) collected in vivo and immature human oocytes discarded for clinical use. Participants/materials, setting, methods Permeability test consisted of incubating oocytes and embryos in 0.005 % solutions of carboxylate-modified polystyrene nanospheres (20, 40 and 100 nm) loaded with a fluorophore emitting at a 505/515 nm for 30 min. Following incubation and washing, samples were observed under a structured illumination fluorescence microscope to determine if particles are present inside ZP (i.e., ZP is permeable to that size of particle) or fluorescence cannot be detected (i.e., particles unable to traverse ZP). Main results and the role of chance ZPs of all species and stages blocked efficiently the pass of 100 nm-sized nanospheres. 40 mm nanospheres were blocked by the ZP of oocytes and zygotes in all species with the exception of rabbit zygotes lacking ZP4. ZP permeability changed during early development, as ZP from murine and bovine cleaved embryos and blastocyst were permeable to 40 nm-sized particles. Finally, with the exception or WT rabbit zygotes, ZP from all oocytes and embryos analyzed were permeable to 20 nm nanospheres. As a fluorescence control, murine and bovine oocytes without ZP were exposed to nanospheres of all sizes, which were clearly visualized attached to the oolema or into the ooplasm. Limitations, reasons for caution Experiments on cleavage and blastocysts stages were performed on animal models, so whether human ZP permeability changes following fertilization remains unknown. Wider implications of the findings Mammalian ZP acts as a selective barrier during early embryo development. Understanding particle size-dependent permeability is crucial to determine embryo susceptibility to viral infection or to signaling mediated by large particles such as extracellular vesicles and exosomes and to assess the impact of oocyte manipulation techniques. Trial registration number Not applicable

Polystyrene nanospheres coated red phosphorus flame retardant for polyamide 66

AbstractAs a halogen‐free flame retardant, red phosphorus (RP) is unstable in air due to its slow oxidation. The shortcomings of RP include strong water absorbing proneness, high friction sensibility and poor thermal stability. The characteristics of polystyrene (PS) are thermostability and fluidity in melt, which can improve the compatibility of RP and the organic matrixes. Using PS as a coating material can improve the characteristics of strong water absorbing proneness of RP. Herein, the polystyrene nanospheres coated RP (PSNS@RP) flame retardant was successfully prepared via emulsion polymerization of styrene. The result shows that the release of phosphine from the PSNS@RP is greatly reduced. The ignition point is increased by about 200°C, and the moisture absorption rate can be reduced by 40 times. The effect of PSNS@RP on the flame retardancy and thermal stability of polyamide 66 (PA66) were studied in detail. Compared with PA66, the limiting oxygen index (LOI) of the PSNS@RP/PA66 composite is increased from 24.8% to 34.2%. The flame retardant grade is enhanced to be UL94 V‐0. The peak heat release rate (PHRR) is decreased from 1444.5 to 420.9 kW m−2, the total heat release (THR) is decreased from 145.8 to 94.2 MJ m−2, and the total smoke production (TSP) is also reduced by 35%. Therefore, the as‐synthesized PSNS@RP has excellent flame retardant and smoke‐suppressing properties for PA66.

Mass Fabrication of WS2 Nanodisks and their Scattering Properties

AbstractHigh‐index all‐dielectric resonators have been developed into an important platform for light manipulation at the nanoscale over the past decade. Although they are widely used as 2D materials, transition metal dichalcogenides (TMDCs), as an emerging all‐dielectric material, have also been used to fabricate optical nanoantennas that support multipolar Mie resonances. However, their fabrication depends heavily on electron‐beam lithography (EBL) or focused ion beam (FIB), which is expensive and time‐consuming for practical applications. To address this issue, here, a fast low‐cost method is put forward which combines polystyrene (PS) nanospheres with physical vapor deposition by electron‐beam evaporation and magnetron sputtering to fabricate WS2 nanodisks in a mass‐production manner. After annealing, the A‐ and B‐exciton features as well as anapole states are observed in the scattering spectra of WS2 nanodisks. The light scattering anisotropy of individual WS2 nanodisks and spectral tunability of the anapole are studied. In addition, absorption enhancement due to the strong field localization of anapole states in hexagonal WS2 nanodisk arrays is numerically demonstrated. This work manifests that this etching‐free method is promising for fabrication of scalable TMDC nanodisks suitable for practical applications.