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To further enhance the safety and energy efficiency of the Fe3O4 preparation experiment, we proposed a strategy for synthesizing monodisperse Fe3O4 microspheres through a one-step solvothermal process. In this environmentally friendly synthesis method, stable FeCl3∙6H2O was utilized as the sole raw material, while ethylene glycol, characterized by its high boiling point and favorable safety profile, served as the solvent. Additionally, inexpensive and readily available urea was selected to function either as a mineralizer or surfactant. Through this one-step solvothermal reaction, the target product of Fe3O4 could be obtained without subsequent calcination under reducing or inert atmospheres, thereby enhancing experimental safety and promoting energy conservation. By controlling the amount of urea added, it became feasible to produce monodisperse magnetic Fe3O4 microspheres characterized by complete crystallinity and high yield. Utilizing the as-synthesized Fe3O4 as a catalyst, we investigated its photocatalytic activity against xylenol orange organic dyes along with its regeneration characteristics. When 40 mmol of urea was incorporated into the reaction mixture, the resulting Fe3O4 sample exhibited optimal photocatalytic performance; a 20 mg/L xylenol orange solution became colorless and transparent after just 1.5 h of UV light irradiation. Furthermore, during five consecutive regeneration cycles, its catalytic activity could be restored to its initial level. Importantly, Fe3O4 demonstrated excellent magnetic sensitivity properties that facilitated rapid targeted separation under an external magnetic field, providing convenience for recovery and collection purposes. [ABSTRACT FROM AUTHOR]

Monodisperse silica of sizes from 0.67 µm to 3.2 µm was synthesized by a low-cost semi-batch technique free from the use of any stabilizer, porogen or surfactant. The effect of precursor (tetraethyl orthosilicate), hydrolyzing agent and catalyst concentration variation on the size, morphology, size distribution and optical properties of silica particles was studied. TEM observation and N2 adsorption-desorption studies showed the existence of a thin porous shell layer covering the outer surface of these particles. Absorption in the UV-Vis range confirmed that E' and oxygen-deficiency centers (ODCs) prevailed. The observed broad photoluminescence including the UV, blue, green and red regions of the spectrum were attributed to the presence of ODCs, self-trapped excitons, hydrogen-related defects and non-bridging-oxygen hole centers respectively. A two-photon guided relaxation of free exciton was found to be a prominent cause of observed luminescence. Highlights: Synthesis of monodisperse silica particles by semi-batch technique. Size range controlled by varying concentrations of reagents. Particles surrounded by a thin porous shell layer. Broad range photoluminescence from UV to red region. Sharp absorption in the UV region and low absorption in the visible region. [ABSTRACT FROM AUTHOR]

Micrometer‐sized monodisperse silicone droplets are prepared through a sol–gel process involving 3‐methacryloxypropylmethyldimethoxysilane (MPDS) at room temperature for 1.5 h in the presence of NH3 as a catalyst. The size of the obtained droplets is controlled by changing the stabilizer concentration and solvent polarity. However, the obtained droplets have not maintained their particulate shape in the dry state due to the absence of a cross‐linking structure. Thus, radical polymerization is performed on the obtained silicone droplets at 70 °C for 2 h; consequently, spherical particles with high monodispersity are observed in the dry state, indicating the presence of a cross‐linked structure. Microcompression tests are conducted to evaluate the mechanical properties of the silicone particles. Initially, the recovery ratio (elasticity) is not high because the molecular weight of the silicone particles is low, ≈600, due to MPDS cyclization (MPDS trimer). Anionic ring‐opening polymerization is therefore performed to extend the molecular weight of the MPDS trimer. Benzyldodecyldimethylammonium bromide and tetrakis[tris(dimethylamino)phosphoranylidenamino]phosphonium chloride are used as catalysts for anionic ring‐opening polymerization. These catalysts increased the molecular weight to ≈2000 and 7600, respectively. Furthermore, the silicone particles obtained through anion ring‐opening polymerization and radical polymerization have high recovery ratios (elasticity). [ABSTRACT FROM AUTHOR]

AbstractGiant liposomes, or giant unilamellar vesicles (GUVs), have been utilized as cell-size bioreactors to replicate the physical and chemical properties of biological cells. However, conventional methods for preparing GUVs typically lack precise control over their size. Several research groups have recently developed microfluidic techniques to create monodisperse GUVs by generating water-in-oil-in-water (W/O/W) droplets with a thin oil layer that subsequently transform into GUVs. However, the formation of a thin oil shell requires the intricate control of the flow rate, which can be both challenging and unstable. In this study, we investigated the design of a two-step flow-focusing microfluidic channel to produce stable W/O/W droplets. These droplets underwent substantial oil layer reduction through spontaneous removal by fluidic shear forces. Consequently, the majority of the oil layer in the W/O/W droplets was reduced, improving uniformity of GUVs. [ABSTRACT FROM AUTHOR]

Although possessing well‐defined nanostructures and excellent multi‐electron redox properties, polyoxometalate clusters have poor intrinsic electrical conductivity and are prone to aggregation due to large surface energy, which makes them difficult to be fully utilized when applying as electrode materials for lithium‐ion batteries. In this paper, monodisperse K7MnV13O38 (MnV13) clusters are achieved by rationally utilizing nano‐sized high conductive carbon dots (CDs) as stabilizers. Benefiting from the fully exposed redox sites of MnV13 clusters (high utilization rate) and sufficient interfaces with carbon dots (extra interfacial energy storage), the optimized MnV13/10CDs anode delivers a high discharge capacity up to 1348 mAh g−1 at a current density of 0.1 A g−1 and exhibits superb rate/cycling capabilities. Density functional theory (DFT) calculations verify that ionic archway channels are formed between MnV13 and CDs, eliminating the bandgap and greatly improving the electron/ion conductivity of MnV13 and CDs. This paper paves a brand‐new way for synthesis of monodisperse clusters and maximization of extra interfacial energy storage. [ABSTRACT FROM AUTHOR]

Traditional methods of decorating silica shells with gold nanoparticles (Au NPs) have problems with being time-consuming (usually over 10 h) and easy agglomeration. An ultrasonic–polymer collaborative-assisted synthesis method is presented in this article for the preparation of monodisperse gold nanoparticles decorated with controlled SiO2 shells (Au NPs@SiO2). Mercaptan-based poly-(ethylene glycol) (SH-PEG) was used to modify Au NPs to improve dispersibility. Then, an ultrasound technique was introduced to accelerate the formation of Au NPs@SiO2 with superior monodispersity within 2 h. Controlling the SiO2 shell thickness (7.2–31.1 nm) can be accomplished by changing the injection of tetraethyl orthosilicate (TEOS) during the synthesis process. An ultrasonic–polymer collaborative-assisted synthesis approach is proposed for the rapid and precise synthesis of monodisperse Au NPs@SiO2 nanoparticles with controllable shell thicknesses. In addition, a fluorescence nanoprobe with an adjustable shell Au NPs@SiO2 was constructed, resulting in a strong enhancement factor of 17 717. Moreover, 29 mg of Au NPs@SiO2 can be synthesized at once (generally less than 10 mg). This method will improve the synthesis of core–shell-structured nanomaterials and promote their application in the biomedical field. [ABSTRACT FROM AUTHOR]

The nitrogen-rich carbon microspheres were prepared by the one-pot hydrothermal synthesis in the presence of resorcinol formaldehyde as the carbon precursor and tetraethylenepentamine (TEPA) as nitrogen precursor as well as the base catalyst, followed by carbonization and activation. Their nitrogen content and microstructure of the nitrogen-rich carbon microspheres could be adjusted by varying the addition of TEPA. The significant enhancement of the microstructure and the nitrogen doping leads to high CO2 adsorption in the activated carbon microspheres. The high nitrogen content of activated sample AMPS-4 was 5.61%, and the large specific surface area and micropore volume were 786.5 m2/g and 0.28 cm3/g, respectively. The activated sample AMCS-4 had the highest CO2 adsorption reaching 5.52 mmol/g and 2.97 mmol/g at 0 and 25 °C, respectively. Compared with EDA-prepared carbon microspheres AMCS-4E, TEPA-prepared carbon microspheres AMCS-4 have stabler chemical adsorption to CO2 due to their higher nitrogen content, which is in corresponds to the higher adsorption heat. The introduction of polyvinylpyrrolidone (PVP) into the system as a stabilizer not only improved the monodispersity of carbon microspheres but also improved the adsorption performance of CO2 by increasing the micropore volume and decreasing the micropore size of the microspheres. The CO2 adsorption of the PVP-assisted prepared sample AMCS-2-P1 reached 4.48 mmol/g and 2.95 mmol/g at 0 °C and 25 °C respectively, which is 0.72 mmol/g and 0.25 mmol/g higher than that of AMCS-2. The carbon microspheres have high CO2 dynamic adsorption capacity, excellent selective adsorption, and good cyclic stability. Highlights: Monodisperse highly N-rich carbon microspheres were prepared by a one-step hydrothermal method. The microspheres have a good monodisperse, improved microstructure, and high N content. The microspheres have high CO2 adsorption capacity, good selective adsorption, and cycling stability. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus (SA) is one of the most common causes of hospital-acquired infections and foodborne illnesses and is commonly found in nature in air, dust, and water. The spread and transmission of SA aerosols in the air has the potential to cause epidemic transmission among humans and between humans and animals. To effectively provide the timely warning of SA aerosols in the atmosphere, the identification and detection of SA aerosol concentrations are required. Due to their homogeneous physicochemical properties, highly monodisperse submicron polystyrene (PS) microspheres can be used as one of the simulants of SA aerosols. In this study, 800 nm monodisperse fluorescent PS (f-PS) microspheres with fluorescence spectra and particle size distribution similar to those of SA were prepared. The 800 nm monodisperse f-PS microspheres had a fluorescence characteristic peak at 465 nm; in aerosols, 800 nm monodisperse f-PS microspheres with a similar particle size distribution to that of SA were further verified, mainly in the range of 500 nm–1000 nm; finally, it was found that the f-PS microspheres still possessed similar fluorescence characteristics after 180 days. The f-PS microspheres prepared in this study are very close to SA in terms of particle size and fluorescence properties, providing a new idea for aerosol analogs of SA. [ABSTRACT FROM AUTHOR]

The facile synthesis of silver nanorods with uniform size and tunable localized surface plasmon resonances is of great significance for plasmon resonance-related applications, such as surface-enhanced Raman spectroscopy (SERS)-based sensing, biomedical diagnostics, and photothermal therapy. However, improving reproducibility is difficult for nonexpert researchers since general synthesis methods involve multiple steps. Addressing this issue, this work develops a facile, effective synthetic strategy for monodisperse silver nanorods with tunable plasmon resonance in the near-infrared region assisted by in situ monitoring via an optical microfiber in the seed formation stage and surfactant-assisted purification of the final product. The optical microfiber monitoring ensures the formation of monodisperse bipyramid templates, guaranteeing the synthesis of the final product. The surfactant-assisted purification of the final product ensures the monodispersity of the final Ag nanorods. This study provides a flexible and alternative approach for nonexpert researchers and may present an opportunity for solving the reproducibility problem faced by nanomaterial synthesis. [ABSTRACT FROM AUTHOR]

The rapid nucleic acid extraction is essential, particularly the communicable diseases pandemic. In this work, aluminum modified Fe3O4 (Fe3O4@Al3+) particles were successfully synthesized by solvthermal method, epoxidation, covalent binding of iminodiacetic acid and Al3+ ions coordination for DNA extraction. Fe3O4@Al3+ particles could greatly improve the efficiency of DNA extraction and the extraction could be totally completed within 15 minutes at the optimum condition. The simple and rapid method is mainly based on the Fe3O4@Al3+ particles, which have large specific surface area, superparamagnetism, and Al3+ ions affinity to DNA. Additionally, several characterizations were carried out to further investigate the features of Fe3O4@Al3+ particles. According to SEM image, the average dimension of monodispersed Fe3O4@Al3+ spheres was around 200 nm. XPS results showed the existence of Al3+ on the surface of Fe3O4 particles, which further demonstrated the success of metal chelation in this material synthesis. The XRD patterns indicated that the Fe3O4@Al3+ particles were the inverse spinel structure as the bare Fe3O4 particles. Good magnetism of Fe3O4@Al3+ particles determined by VSM indicated that this material could be easily separated from the reaction system. To summarize, Fe3O4@Al3+ particles is expected to play an important role in future DNA extraction due to remarkable performance. The DNA separation media Fe3O4@Al3+ particles were successfully synthesized. DNA adsorption was effectively achieved by Fe3O4@Al3+ particles based on metal chelation. DNA extraction was significantly boosted by Fe3O4@Al3+ particles. [ABSTRACT FROM AUTHOR]

Previous numerical studies of pulmonary drug delivery using metered-dose inhalers (MDIs) often neglected the momentum transfer from droplets to fluid. However, Kolmogorov length scales in MDI flows can be comparable to the droplet sizes in the orifice vicinity, and their interactions can modify the spray behaviors. This study aimed to evaluate the two-way coupling effects on spray plume evolutions compared to one-way coupling. The influences from the mass loading, droplet size, and inhaler type were also examined. Large-eddy simulation and Lagrangian approach were used to simulate the flow and droplet motions. Two-way coupled predictions appeared to provide significantly improved predictions of the aerosol behaviors close to the Ventolin orifice than one-way coupling. Increasing the applied MDI dose mass altered both the fluid and aerosol dynamics, notably bending the spray plume downward when applying a dose ten times larger. The droplet size played a key role in spray dynamics, with the plume being suppressed for 2-µm aerosols and enhanced for 20-µm aerosols. The Kolmogorov length scale ratio dp/η correlated well with the observed difference in spray plumes, with suppressed plumes when dp/η < 0.1 and enhanced plumes when dp/η > 0.1. For the three inhalers considered (Ventolin, ProAir, and Qvar), significant differences were predicted using two-way and one-way coupling despite the level and manifestation of these differences varied. Two-way coupling effects were significant for MDI sprays and should be considered in future numerical studies.

[Display omitted] • Highly dispersed ZnSe QDs are synthesized by electron beam radiation with EDTA. • ZnSe QDs are synthesized in minutes at room-temperature without toxic reductant. • EDTA can effectively inhibit the aggregation and improve the water-solubility. • ZnSe QDs exhibit a large bandgap of 4.3 eV with blue photoluminescence at 435 nm. • The nucleation reaction and growth mechanism of ZnSe QDs are proposed. ZnSe quantum dots (QDs) have attracted attentions due to small size and strong fluorescence. However, ZnSe QDs are easy to agglomerate and insoluble in aqueous solutions, which limits their practical applications. Herein, we report a novel strategy for synthesizing highly dispersed and water-soluble ZnSe QDs by electron beam radiation with the aid of EDTA within only a few minutes at room temperature without any reduction reagents. In the reaction system, EDTA plays an important role in controlling the quantum size of crystal growth, inhibiting the agglomeration of ZnSe QDs and improving the water solubility. ZnSe QDs exhibit a large bandgap of 4.3 eV, significantly blue shifted compared with bulk ZnSe due to the quantum confinement effect. Constructed the structural model by MS, the nucleation reaction and growth mechanism of ZnSe QDs are proposed. Electron-beam irradiation can be widely used to synthesize water-soluble semiconductor QDs with promising application in biological imaging. [ABSTRACT FROM AUTHOR]

Exploring aqueous nano-fabrication with monodisperse and hierarchical characteristics is fundamentally and technically significant. Herein, we discover that inter-particle nano—nano scale interactions profoundly affect the products' morphology ranging from polydisperse — monodisperse to individual — hierarchical manipulation. Accordingly, we present a "nucleation-growth-dispersion triple modulation" strategy for fabricating monodisperse Cu2−xE (E = S, Se, Te) nanocrystals (NCs) and supraparticles (SPs). Such full-process and cross-scale control is conducted by two rationally selected ligands (cysteine and citrate molecules), which are responsible for atom/molecule—nano and nano—nano interaction modulations, respectively. Cysteine reacts with the cations and forms low reactive (cysteine-Cu+)n coordination polymers, which overcomes the commonly concerned nucleation and particle growth induced polydispersity. Citrate, by virtue of its strong negative charge modulated NC—NC interactions, decides the products morphology from polydisperse products to monodisperse NCs to monodisperse hierarchical SPs. These findings not only present new insights into aqueous nano-synthesis chemistry but provide an eco-friendly system for versatile and high-quality nano-entity fabrication. [ABSTRACT FROM AUTHOR]

In the present study, the mutual diffusivity D11 in binary mixtures of water with technical polydisperse poly(ethylene) glycol (PEG) blends with molar masses of (1000, 4000, or 6000) g⋅mol−1 as well as with a purified monodisperse PEG homolog with a polymerization number of 21 and a molar mass of 943 g⋅mol−1 was investigated by heterodyne dynamic light scattering (DLS) as a function of temperature and/or PEG concentration. The measured D11 for technical PEG 1000 and pure PEG 943 match within the experimental uncertainties and agree well with the available literature data. D11 decreases with increasing molar mass of the PEGs at constant temperature and weight fraction. For the technical PEG 4000, it could be shown that D11 increases with increasing temperature and exhibits a nonlinear concentration dependence. This study demonstrates that heterodyne DLS can be applied for the reliable determination of D11 of aqueous solutions of PEGs over a broad range of PEG weight fractions from 0.01 up to the solubility limit with an average expanded uncertainty (k = 2) of 5.5 %. Moreover, the results show that monodisperse PEGs are suitable model systems for studying the diffusion behavior of bimodal and also multimodal particulate systems. [ABSTRACT FROM AUTHOR]

The stepwise synthesis of monodisperse polyethylene glycols (PEGs) and their derivatives usually involves using an acid-labile protecting group such as DMTr and coupling the two PEG moieties together under basic Williamson ether formation conditions. Using this approach, each elongation of PEG is achieved in three steps – deprotection, deprotonation and coupling – in two pots. Here, we report a more convenient approach for PEG synthesis featuring the use of a base-labile protecting group such as the phenethyl group. Using this approach, each elongation of PEG can be achieved in two steps – deprotection and coupling – in only one pot. The deprotonation step, and the isolation and purification of the intermediate product after deprotection using existing approaches are no longer needed when the one-pot approach is used. Because the stepwise PEG synthesis usually requires multiple PEG elongation cycles, the new PEG synthesis method is expected to significantly lower PEG synthesis cost.

Uniform Fe 3 O 4 submicron spheres assembled by tiny nanocrystals were fabricated via a facile one-step solvothermal strategy. The morphology, crystal structure, mesoporous characteristics, elemental composition and magnetic properties of the resultant magnetic particles were investigated extensively through various characterization techniques. The resulting Fe 3 O 4 submicron spheres were nearly monodisperse with an average diameter of 508 nm and demonstrated typical mesoporous structures and superparamagnetic behavior. The rheological responses of magnetorheological (MR) suspension composed of Fe 3 O 4 submicron spheres to different intensity of magnetic fields were investigated and the sedimentation stability tests were conducted and compared with that of carbonyl iron particles. The formed MR fluid behaved as Newtonian fluid without an external magnetic field and turned into Bingham behavior under the action of magnetic field. In addition, no significant settlement was observed in the recording period, showing an excellent sedimentation stability for the developed MR fluid. • Uniform hierarchical Fe 3 O 4 submicron spheres were synthesized by a solvothermal approach. • Mesoporous structure, high saturation magnetization and superparamagnetic behavior. • A stable magnetorheological fluid composed of Fe 3 O 4 submicron spheres. • Typical Bingham fluid behavior and high sedimentation stability. [ABSTRACT FROM AUTHOR]

Sequence‐defined synthetic oligomers and polymers provide unprecedented opportunities for polymer chemists to finely control properties such as chain folding, self‐assembly, and optoelectronic performance of materials. However, absolute control over both chain‐length and monomer sequence has been a long‐standing "grand challenge" for decades. Herein, we report a novel strategy to synthesize monodisperse sequence‐defined conjugated oligomers in a homogeneous manner by temperature cycling, thereby achieving single‐monomer precision in conjugated polyheterocycles. A series of sequence‐defined oligomers with up to twelve repeating units, four different monomers, and various sequences were successfully synthesized. Monomer sequence was also proved to affect optical properties. We believe this strategy not only exhibits general applicability to the synthesis of group 16 conjugated oligomers and polymers, but also has far‐reaching potential for other polymer systems. [ABSTRACT FROM AUTHOR]

Ultrasmall monodisperse NiO nanoparticles (7–9 nm) were synthesized through thermal decomposition of Ni-oleylamine complexes. Various measurement techniques involving Fourier-transform infrared spectroscopy (FT-IR), diffuse reflectance UV-Vis spectroscopy (DRS), X-ray diffractometer (XRD), energy dispersive X-ray analysis (EDX), scanning electron microscopy (SEM), dynamic light scattering technique (DLS), and vibrating sample magnetometer (VSM) were employed to characterize the synthesized catalyst. Propargylamine derivatives were synthesized with aldehydes, terminal alkynes and primary amines through a one-pot A3-coupling reaction by using a 3 mol% amount of the NiO nanocrystals at 80 °C under solvent-free conditions with good to excellent yields. The structures of the products were confirmed by 1H and 13C NMR spectroscopy. The catalyst presents many advantages including being environmentally friendly, easy to recover, reusable, stable, and applicable to a wide variety of substrates, as well as having cost-effective preparation.

Water-in-water (W/W) Pickering emulsions, exhibit considerable potential in the food and pharmaceutical fields owing to their compartmentalization and high biocompatibility. However, constrained by the non-uniform distribution of shear forces during emulsification or the spatial obstruction in polydimethylsiloxane (PDMS) passive microfluidic platform, the existing methods cannot generate monodisperse W/W Pickering emulsions with high particle coverage rate, thereby limiting their applications. Herein, a novel microfluidic system is designed for the preparation of monodisperse and highly particle-covered W/W Pickering emulsions under mild conditions. pH-responsive Polyethylene glycol (PEG)/phosphate aqueous two-phase system (ATPS) is used for the emulsions' preparation. Notably, a coverage rate of 96 ± 3 % is obtained by adjusting the length of the helical coiled tube, as well as the size and contact angle of genipin cross-linked BSA (BSA-GP) particles. Moreover, these W/W Pickering emulsions, with surfaces almost completely covered, can maintain monodisperse (N coal = 1.18 ± 0.03) for one day. Furthermore, the results of ranitidine hydrochloride (RH) release demonstrated that the drug release rate of W/W Pickering emulsions in the simulated gastric fluid (SGF) was 10 times faster than that in the neutral solution. We believe that the highly particle-covered monodisperse W/W Pickering emulsions possess great potential applications in bioencapsulation for foods and drug delivery. • A microfluidic system was designed based on Dean vortex acceleration mass transfer. • BSA-GP Pickering particles with adjustable size and hydrophobicity were prepared. • Monodisperse W/W Pickering emulsions with high particle coverage were prepared. • PEG/phosphate pickering emulsions showed pH responsive in controlled drug release. [ABSTRACT FROM AUTHOR]

We succeeded in freeze-drying monodisperse microbubbles without degrading their performance, that is, their monodispersity in size and echogenicity. We used microfluidic technology to generate cryoprotected highly monodisperse microbubbles (coefficient of variation [CV] <5%). By using a novel retrieval technique, we were able to freeze-dry the microbubbles and resuspend them without degradation, that is, keeping their size distribution narrow (CV <6%). Acoustic characterization performed in two geometries (a centimetric cell and a millichannel) revealed that the resuspended bubbles conserved the sharpness of the backscattered resonance peak, leading to CVs ranging between 5% and 10%, depending on the geometry. As currently observed with monodisperse bubbles, the peak amplitudes are one order of magnitude higher than those of commercial ultrasound contrast agents. Our work thus solves the question of storage and transportation of highly monodisperse bubbles. This work might open pathways toward novel clinical non-invasive measurements, such as local pressure, impossible to carry out with the existing commercial ultrasound contrast agents. [ABSTRACT FROM AUTHOR]

The microspheres prepared by the microfluidic‐assisted internal gelation process are still challenging to reach the millimeter size due to the large gravity. The gravity would affect the sphericity and size uniformity of microspheres. The improved microfluidic‐assisted internal gelation process is designed and optimized to produce large‐sized monodisperse ceramic microspheres with good sphericity. The movement mechanism of millimeter‐sized sol droplets and gel microspheres in the microchannel is summarized and the state of the dispersed phase entering the measuring cylinder is controlled. The friction between the gel microspheres and the tubing wall is reduced as much as possible, and ZrO2 ceramic microspheres of 500 ± 5 μm with good sphericity are prepared with the broth at room temperature. The mechanism of sol droplets entering the oil surface is explored to demonstrate the superiority of the improved microfluidic‐assisted internal gelation process. The improved microfluidic‐assisted internal gelation process could be directly extended to preparing other millimeter‐sized monodisperse ceramic microspheres. [ABSTRACT FROM AUTHOR]

In this study, monodisperse magnetic carbon microspheres were successfully synthesized through the carbonization of phenolic resin encapsulated Fe3O4 core‐shell structures. The magnetic carbon microspheres showed high performance in ultrafast extraction and separation of trace triazine herbicides from environmental water samples. Under optimized conditions, both the adsorption and desorption processes could be achieved in 2 min, and the maximum adsorption capacity for simazine and prometryn were 387.6 and 448.5 μg/g. Coupled with high‐performance liquid chromatography‐ultraviolet detection technology, the detection limit of triazine herbicides was in the range of 0.30–0.41 ng/mL. The mean recoveries ranged from 81.44 to 91.03% with relative standard deviations lower than 7.47%. The excellent magnetic solid‐phase extraction performance indicates that magnetic carbon microspheres are promising candidate adsorbents for the fast analysis of environmental contaminants. [ABSTRACT FROM AUTHOR]

Objectives: Subharmonic aided pressure estimation (SHAPE) has been shown effective for noninvasively measuring hydrostatic fluid pressures in a variety of clinical applications. The objective of this study was to explore potential improvements in SHAPE sensitivity using monodisperse microbubbles. Methods: Populations of monodisperse microbubbles were created using a commercially available microfluidics device (Solstice Pharmaceuticals). Size distributions were assessed using a Coulter Counter and stability of the distribution following fabrication was evaluated over 24 hours. Attenuation of the microbubble populations from 1 to 10 MHz was then quantified using single element transducers to identify each formulation's resonance frequency. Frequency spectra over increasing driving amplitudes were investigated to determine the nonlinear phases of subharmonic signal generation. SHAPE sensitivity was evaluated in a hydrostatic pressure‐controlled water bath using a Logiq E10 scanner (GE Healthcare). Results: Monodisperse lipid microbubble suspensions ranging from 2.4 to 5.3 μm in diameter were successfully created and they showed no discernable change in size distribution over 24 hours following activation. Calculated resonance frequencies ranged from 2.1 to 6.3 MHz and showed excellent correlation with microbubble diameter (R2 > 0.99). When investigating microbubble frequency response, subharmonic signal occurrence was shown to begin at 150 kPa peak negative pressure, grow up to 225 kPa, and saturate at approximately 250 kPa. Using the Logiq E10, monodisperse bubbles demonstrated a SHAPE sensitivity of −0.17 dB/mmHg, which was nearly twice the sensitivity of the commercial polydisperse microbubble currently being used in clinical trials. Conclusions: Monodisperse microbubbles have the potential to greatly improve the sensitivity of SHAPE for the noninvasive measurement of hydrostatic pressures. [ABSTRACT FROM AUTHOR]

Patterns of assembled colloidal particles can form on substrates due to solvent evaporation, and here we studied such phenomena in the drying of monodispersed colloidal hydrochar dispersions prepared by the hydrothermal carbonization of glucose and purified by dialysis. During the evaporation of water, line patterns or, in some cases, mud-like patterns formed. The line formation was investigated as a function of the pH of the dispersion, substrate shape, particle concentration, and concentration of sodium dodecylsulfate (SDS). The lines comprised dense assemblies of hydrochar particles. The line width increased with the successive evaporation of water. Sharper lines formed with the addition of SDS, which was ascribed to the effects of solubilization or moderated interactions. At greater particle concentrations, we also observed a continuous layer of colloidal particles between the lines. A mechanism for the line pattern formation derived from the literature on other colloids was proposed. Mud-like patterns formed on the substrate in concentrated samples without SDS addition and were put in the context of the formation of cracks in the drying of colloidal coatings. Hydrochars belong to carbon-rich colloids, which are of fundamental and technological importance. This research could be useful for in situ line printing within microfluidic devices, for example. [ABSTRACT FROM AUTHOR]

Highly monodisperse nanostructures are becoming the centre of focus in the field of material science towards the application of sensors, photocatalysis, gas sensing, antibacterial activity, drug delivery and energy applications. Monodisperse resembles uniform nanostructures towards better device performances and applications. In order to minimize the reaction time and characterization costs, an attempt has been made for development of a prediction model for the synthesis of monodisperse silica nanospheres using Adaptive Neuro-Fuzzy Inference System (ANFIS) software. Experimental parameters of the Stober method such as precursor's ratio (ethanol, water and ammonia), Tetraethyl Orthosilicate (TEOS) and sphere size were predicted in the model. The results from the prediction model were used for carrying out experimentation on thin films using vertical deposition technique. The prepared substrates were characterized by FE-SEM & XRD analysis. Obtained Experimental results shows that nanosphere with a size range of 200- 250 nm will form monodisperse layer. XRD analysis confirms the amorphous nature of SiO2 film. ANFIS has predicted best suitable size of silica nanospheres and optimized precursor's ratios for attaining highly monodisperse structure. The optimized parameters predicted from the ANFIS network matches well with the experimental results.

An in-depth review on a new ultrasonic micro-droplet generator which utilizes megahertz (MHz) Faraday waves excited by silicon-based multiple Fourier horn ultrasonic nozzles (MFHUNs) and its potential applications is presented. The new droplet generator has demonstrated capability for producing micro droplets of controllable size and size distribution and desirable throughput at very low electrical drive power. For comparison, the serious deficiencies of current commercial droplet generators (nebulizers) and the other ultrasonic droplet generators explored in recent years are first discussed. The architecture, working principle, simulation, and design of the multiple Fourier horns (MFH) in resonance aimed at the amplified longitudinal vibration amplitude on the end face of nozzle tip, and the fabrication and characterization of the nozzles are then described in detail. Subsequently, a linear theory on the temporal instability of Faraday waves on a liquid layer resting on the planar end face of the MFHUN and the detailed experimental verifications are presented. The linear theory serves to elucidate the dynamics of droplet ejection from the free liquid surface and predict the vibration amplitude onset threshold for droplet ejection and the droplet diameters. A battery-run pocket-size clogging-free integrated micro droplet generator realized using the MFHUN is then described. The subsequent report on the successful nebulization of a variety of commercial pulmonary medicines against common diseases and on the experimental antidote solutions to cyanide poisoning using the new droplet generator serves to support its imminent application to inhalation drug delivery.

Selections of surfactants and their concentrations are both critical factors in emulsion polymerization for preparation of polymer nanoparticles with low polydispersity (i.e., low coefficient of variation of particle sizes, CV). Our previous report revealed that employment of an anionic surfactant of sodium octadecyl sulfate (SOS), which has a critical micellization concentration (CMC) much lower than sodium dodecyl sulfate (SDS) commonly used in conventional emulsion polymerization, is very effective for reducing particle sizes without deteriorating their monodispersity. However, the mechanism on formation of small polymer particles with low polydispersity was still not clarified in the previous report. In this report, the number (NP) and CV of polymer nanoparticles formed in the polymerization of styrene (St) using SOS were compared with the conventional polymerization using SDS in a wide range of surfactant concentrations including both their CMCs. The comparisons in NP and CV were also performed in copolymerizations with methylmethacrylate (MMA) less hydrophobic than St. These experimental comparisons in NP and CV have rationalized the St/MMA copolymerization using a low-CMC surfactant highly suitable for attaining the formation of nanoparticles with low polydispersity. [ABSTRACT FROM AUTHOR]

We report the synthesis of α-Ag2S nanoparticles (NPs) by one-step laser ablation of a silver target in aqueous solution of thiourea (Tu, CH4N2S) mixed with cationic cetyltrimethylammonium bromide (CTAB) as surfactant. The effect of the CTAB surfactant on the structural, morphological, optical, and elemental composition of Ag2S NPs was evaluated using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and UV–vis spectroscopy. The optical absorption decreased and the optical energy gap of α-Ag2S increased from 1.5 to 2 eV after the CTAB surfactant was added to the Tu solution. XRD studies revealed that the synthesized Ag2S NPs were polycrystalline with a monoclinic structure and that crystallinity of the nanoparticles was improved after adding CTAB. Raman studies revealed the presence of peaks related to Ag–S bonds (Ag modes) and the longitudinal optical phonon 2LO mode. Scanning electron microscopy investigations confirmed the production of monodisperse Ag2S NPs when using the CTAB surfactant. The optoelectronic properties of α-Ag2S/p-Si photodetector, such as current–voltage characteristics and responsivity in the dark and under illumination, were also improved after using the CTAB surfactant. The responsivity of the photodetector increases from 0.64 to 1.85 A/W at 510 nm after adding CTAB. The energy band diagram of the α-Ag2S/p-Si photodetector under illumination was constructed. The fabricated photodetectors exhibited reasonable stability after three weeks of storage under ambient conditions with a responsivity of 70% of the initial value.

Monodisperse pure and nickel-doped iron oxide NixFe3-xO4 (x ​= ​0.00, 0.02, 0.04, and 0.06) nanospheres were synthesized by hydrothermal method. The synthetic method was featured by using a structure directing agent, namely, anhydrous sodium acetate and ferric ions source, iron (III) chloride in an ethylene glycol solution without any kind of surfactant or template involved. The molar ratio of salts to anhydrous sodium acetate was optimized to 1:4 to get monodispersed and uniform spherical nanostructures. The sensing response of nickel doped iron oxide to different gases such as acetone, ammonia, sulphur dioxide, hydrogen sulphide, ethanol and methanol are accomplished at room temperature with the gas concentration of 5 ​ppm and was found selective towards acetone with response 29.9%. The response of NixFe3-xO4 (x ​= ​0.06) nanospheres were found to be 29.9%, 46%, 66%, 106%, and 174% towards 5, 10, 15, 20 and 25 ​ppm acetone concentration respectively. The response and recovery time at 5 ​ppm acetone concentration was found to be 94 ​s and 68 ​s respectively. Based on the reproducibility and stability test, it was observed that the fabricated sensor based on nickel doped iron oxide is highly reliable. The energy band diagram of the sensing mechanism of NixFe3-xO4 (x ​= ​0.06) nanospheres upon exposure to air and acetone atmosphere are presented.

Monodisperse pure and nickel-doped iron oxide NixFe3-xO4 (x ​= ​0.00, 0.02, 0.04, and 0.06) nanospheres were synthesized by hydrothermal method. The synthetic method was featured by using a structure directing agent, namely, anhydrous sodium acetate and ferric ions source, iron (III) chloride in an ethylene glycol solution without any kind of surfactant or template involved. The molar ratio of salts to anhydrous sodium acetate was optimized to 1:4 to get monodispersed and uniform spherical nanostructures. The sensing response of nickel doped iron oxide to different gases such as acetone, ammonia, sulphur dioxide, hydrogen sulphide, ethanol and methanol are accomplished at room temperature with the gas concentration of 5 ​ppm and was found selective towards acetone with response 29.9%. The response of NixFe3-xO4 (X=​0.06) nanospheres were found to be 29.9%, 46%, 66%, 106%, and 174% towards 5, 10, 15, 20 and 25 ​ppm acetone concentration respectively. The response and recovery time at 5 ​ppm acetone concentration was found to be 94 ​s and 68 ​s respectively. Based on the reproducibility and stability test, it was observed that the fabricated sensor based on nickel doped iron oxide is highly reliable. The energy band diagram of the sensing mechanism of NixFe3-xO4 (X=​0.06) nanospheres upon exposure to air and acetone atmosphere are presented. [ABSTRACT FROM AUTHOR]

[Display omitted] Self-aggregated colloids can be used for the preparation of materials, and we studied long rod-like aggregates formed on the evaporation of water from dispersed particles of colloidal hydrochar. The monodispersed hydrochar particles (100–200 nm) were synthesized by the hydrothermal carbonization of glucose and purified through dialysis. During the synthesis they formed colloidal dispersions which were electrostatically stable at intermediate to high pH and at low ion strengths. On the evaporation of water, macroscopically large rods formed from the dispersions at intermediate pH conditions. The rods formed at the solid-water interface orthogonally oriented with respect to the drying direction. Pyrolysis rendered the rods highly porous without qualitatively affecting their shape. A Cu-Si alloy was reactively infiltrated into the in-situ pyrolyzed hydrochars and composites of tricopper silicide (Cu 3 Si)-silicon carbide (SiC)/carbon formed. During this process, the Si atoms reacted with the C atoms, which in turned caused the alloy to wet and further react with the carbon. The shape of the underlying carbon template was maintained during the reactions, and the formed composite preparation was subsequently calcined into a Cu 3 Si-SiC-based replica of the rod-like assemblies of carbon-based colloidal particles. Transmission and scanning electron microscopy, and X-ray diffraction were used to study the shape, composition, and structure of the formed solids. Further studies of materials prepared with reactive infiltration of alloys into self-aggregated and carbon-based solids can be justified from a perspective of colloidal science, as well as the explorative use of hydrochar prepared from real biomass, exploration of the compositional space in relation to the reactive infiltration, and applications of the materials in catalysis. [ABSTRACT FROM AUTHOR]

The commonly used synthetic methods of narrow or monodisperse polymer microspheres are reviewed, including precipNation polymerization, dispersion polymerization, emulsion polymerization, seed polymerization, and membrane emulsification, etc・ Moreover, it also covers the functionalization of microspheres from the perspective of the preparation of magnetic microspheres, porous microspheres, temperature/pH-responsive microspheres, and cationic microspheres ・ The recent and future development direction of monodispersed microspheres is finally suggested, including the combination of multiple polymerization methods, the synthesis of multifunctional monodispersed microspheres and the realization of mass production. [ABSTRACT FROM AUTHOR]

[Display omitted] • BODIPY 665/676 is a valid marker for local peroxyl radical formation. • Smaller droplets show faster lipid oxidation in polydisperse emulsions. • Colloid mill emulsions show large heterogeneity in protein and lipid oxidation. • Microfluidic emulsification results in slow protein and lipid oxidation. Spatiotemporal assessment of lipid and protein oxidation is key for understanding quality deterioration in emulsified food products containing polyunsaturated fatty acids. In this work, we first mechanistically validated the use of the lipid oxidation-sensitive fluorophore BODIPY 665/676 as a semi-quantitative marker for local peroxyl radical formation. Next, we assessed the impact of microfluidic and colloid mill emulsification (respectively producing mono- and polydisperse droplets) on local protein and lipid oxidation kinetics in whey protein isolate (WPI)-stabilized emulsions. We further used BODIPY 581/591 C11 and CAMPO-AFDye 647 as colocalisation markers for lipid and protein oxidation. The polydisperse emulsions showed an inverse relation between droplet size and lipid oxidation rate. Further, we observed less protein and lipid oxidation occurring in similar sized droplets in monodisperse emulsions. This observation was linked to more heterogeneous protein packing at the droplet surface during colloid mill emulsification, resulting in larger inter-droplet heterogeneity in both protein and lipid oxidation. Our findings indicate the critical roles of emulsification methods and droplet sizes in understanding and managing lipid oxidation. [ABSTRACT FROM AUTHOR]

DNA hydrogels are notable for their biocompatibility and ability to incorporate DNA information and computing properties into self-assembled micrometric structures. These hydrogels are assembled by the thermal gelation of DNA motifs, a process which requires a high salt concentration and yields polydisperse hydrogel particles, thereby limiting their application and physicochemical characterization. In this study, we demonstrate that single, uniform DNA hydrogel particles can form inside aqueous/aqueous two-phase systems (ATPSs) assembled in a microwell array. In this process, uniform dextran droplets are formed in a microwell array inside a microfluidic device. The dextran droplets, which contain DNA motifs, are isolated from each other by an immiscible PEG solution containing magnesium ions and spermine, which enables the DNA hydrogel to undergo gelation. Upon thermal annealing of the device, we observed the formation of an aqueous triple-phase system in which uniform DNA hydrogel particles (the innermost aqueous phase) resided at the interface of the aqueous two-phase system of dextran and PEG. We expect ATPS microdroplet arrays to be used to manufacture other hydrogel microparticles and DNA/dextran/PEG aqueous triple-phase systems to serve as a highly parallel model for artificial cells and membraneless organelles.

DNA hydrogels are notable for their biocompatibility and ability to incorporate DNA information and computing properties into self-assembled micrometric structures. These hydrogels are assembled by the thermal gelation of DNA motifs, a process which requires a high salt concentration and yields polydisperse hydrogel particles, thereby limiting their application and physicochemical characterization. In this study, we demonstrate that single, uniform DNA hydrogel particles can form inside aqueous/aqueous two-phase systems (ATPSs) assembled in a microwell array. In this process, uniform dextran droplets are formed in a microwell array inside a microfluidic device. The dextran droplets, which contain DNA motifs, are isolated from each other by an immiscible PEG solution containing magnesium ions and spermine, which enables the DNA hydrogel to undergo gelation. Upon thermal annealing of the device, we observed the formation of an aqueous triple-phase system in which uniform DNA hydrogel particles (the innermost aqueous phase) resided at the interface of the aqueous two-phase system of dextran and PEG. We expect ATPS microdroplet arrays to be used to manufacture other hydrogel microparticles and DNA/dextran/PEG aqueous triple-phase systems to serve as a highly parallel model for artificial cells and membraneless organelles. [ABSTRACT FROM AUTHOR]

Monodisperse polystyrene microspheres with different functional groups have important applications in both the medical and analytical fields. In this study, we prepared monodisperse microspheres with sulfonic acid or carboxyl groups using soap-free emulsion polymerization (SFEP) with potassium persulfate as the initiator. A series of monodisperse polystyrene microspheres with sizes between 100 and 500 nm were successfully prepared by copolymerizing different types of ionic monomers at different concentrations. The microspheres were characterized by using dynamic light scattering (DLS), Zeta potential measurements (ZP), FT-IR spectroscopy, and transmission electron microscopy (TEM). The mechanism of the particle nucleation and growth were studied by combining the changes in particle size and the number of particles. The results showed that the addition of hydrophilic comonomers like sodium p-styrene sulfonate, acrylic acid, and methacrylic acid significantly improved the stability of the polystyrene microspheres and promoted particle nucleation, resulting in less particle aggregation and microspheres with smaller sizes. [ABSTRACT FROM AUTHOR]