Micromachines
·
2015
·Vol. 6
·期 9
·1331-1345
·
IF 1.269
Juan Wang,Mingliang Jin,Tao He,Guofu Zhou,Lingling Shui
We report on the microfluidic induced monodispersed microdroplet generation and assembly in confined microchannels. Two and three dimensional close-packed droplet lattices were obtained in microfluidic devices by adjusting the channel geometry, the fluidic flow rates and the monodispersed droplet size. The droplet packing was mainly caused by the volumetric effect and capillarity in confined microchannels. Polymerizable fluids were also investigated to demonstrate the effect of fluidic properties on the microdroplet generation and assembly, which could find interesting applications in the future. This approach would be helpful to fundamentally understand the mechanism of self-assembly process of particles in confined microstructures, and practically be applied in sensing and energy storage devices.Keywords:microfluidics;microdroplet;self-assembly;close-packed configuration
研究领域:
物理学
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材料科学
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化学工程
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DOI
高影响因子
Chemical Science
·
2025
·
IF 7.4
Yue-Wen Zhou,Ming-Yang Jia,Jun-Lei Yang,Qinlei Liu,Zhenfeng Cai
The influence of electric fields (EFs) on chemical reactions has attracted significant interest due to their ability to modulate reaction rates, pathways, and selectivity. Although EFs have been experimentally demonstrated to facilitate various reactions, clearer evidence for their role in covalent condensation has remained limited. Herein, we provide experimental evidence of electric-field-induced covalent condensation of boronic acids, utilizing the strong EFs at the air-liquid interface of microdroplets to induce the reaction. Microdroplet-based chemistry provides interfacial electric field intensities as high as ca. 109 V/m, offering a robust platform for the systematic investigation of boronate linkage formation and subsequent condensation of boronic acids. Our results confirm the role of EFs in facilitating room-temperature condensation of boronic acids, providing direct insights into the electric-field-induced polymerization process and presenting an experimental approach for investigating these processes in solution.
研究领域:
化学
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材料科学
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DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2023
·
IF 11.4
Jinzhao Wang,Di Huang,Fengxia Chen,Jianhua Chen,Hongyu Jiang,Yifan Zhu,Chuncheng Chen,Jincai Zhao
Fe(III) and carboxylic acids are common compositions in atmospheric microdroplet systems like clouds, fogs, and aerosols. Although photochemical processes of Fe(III)–carboxylate complexes have been extensively studied in bulk aqueous solution, relevant information on the dynamic microdroplet system, which may be largely different from the bulk phase, is rare. With the help of the custom-made ultrasonic-based dynamic microdroplet photochemical system, this study examines the photochemical process of Fe(III)–citric acid complexes in microdroplets for the first time. We find that when the degradation extent of citric acid is similar between the microdroplet system and the bulk solution, the significantly lower Fe(II) ratio is present in microdroplet samples due to the rapider reoxidation of photogenerated Fe(II). However, by replacing citric acid with benzoic acid, no much difference in the Fe(II) ratio between microdroplets and bulk solution is observed, which indicates distinct reoxidation pathways of Fe(II). Moreover, the presence of •OH scavenger, namely, methanol, greatly accelerates the reoxidation of photogenerated Fe(II) in both citric acid and benzoic acid situations. Further experiments reveal that the high availability of O2 and the citric acid- or methanol-derived carbon-centered radicals are responsible for the rapider reoxidation of Fe(II) in iron–citric acid microdroplets by prolonging the length of HO2•- and H2O2-involved radical reaction chains. The results in this study may provide a new understanding about iron–citric acid photochemistry in atmospheric liquid particles, which can further influence the photoactivity of particles and the formation of secondary organic aerosols.
研究领域:
大气科学
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环境化学
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DOI
PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Hanpeng Gao,Yan Liu,Guoyong Wang,Shuyi Li,Zhiwu Han,Luquan Ren
Smart surfaces that can manipulate droplets or fluids have attracted intense attention because of their essential application prospects. However, it is still a challenge to obtain multifunctional integrated metal platforms that can simultaneously manipulate water/oil droplets and water/oil fluids. Here, inspired by the structure and wettability of natural reed leaves and lotus leaves, dual biomimetic platforms with switchable and anisotropic/isotropic wettability were prepared on copper by laser processing, chemical etching, and mixed thiols modification. The wettability of the integrated platforms can respond to the change of external pH value and reversibly switch between superhydrophobicity and underwater superoleophobicity. The areas of “reed leaf” structure and “lotus leaf” structure on the biomimetic platform have anisotropic and isotropic wettability, respectively. Significantly, by rationally designing the distribution of bionic structures, the dual biomimetic platforms can simultaneously manipulate water/oil droplets and water/oil fluids. This work not only provides advanced integrated biomimetic platforms and interesting design strategies, but also has important reference value in the development of new metal microfluidic devices.
研究领域:
材料科学
·
生物学
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产品关联
DOI
高影响因子
ULTRASONICS SONOCHEMISTRY
·
2023
·
IF 8.4
Zongbo Zhang,Changbin Xu,Shiliang Song,Yan Ding,Nan Meng,Xuesheng Liu,Yuan Zhang,Liang Gong,Wenting Wu
Ag 2 S quantum dots (QDs) have aroused extensive concerns in intravital imaging field due to their merits of narrow bandgap, low biological toxicity and decent fluorescence emission properties in the second near-infrared (NIR-II) window. However, low quantum yield (QY) and poor uniformity of Ag 2 S QDs are still main obstacles for its application. In this work, a novel strategy of utilizing ultrasonic field is presented, which can enhance the microdroplet-based interfacial synthesis of Ag 2 S QDs. The ultrasound increases the presence of ions at the reaction sites by enhancing the ion mobility in the microchennels. Therefore, the QY is enhanced from 2.33 % (optimal QY without ultrasound) to 8.46 %, which is the highest value of Ag 2 S ever reported without ion-doping. Also, the decrease of the corresponding full width at half maximum (FWHM) from 312 nm to 144 nm indicates the obvious uniformity improvement of the obtained QDs. Further mechanism exploration illustrates that ultrasonic cavitation significantly increases the interfacial reaction sites by splitting the droplets. Meanwhile, the acoustic flow field strengthens the ion renewal at the droplet interface. Consequently, the mass transfer coefficient increases by more than 500 %, which is favorable to improve both the QY and quality of Ag 2 S QDs. This work serves both fundamental research and practical production for the synthesis of Ag 2 S QDs.
研究领域:
材料科学
·
纳米技术
·
生物医学工程
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DOI
PubMed
高影响因子
CHEMOSPHERE
·
2025
·
IF 8.1
Siyu Liu,Xinyue Zhao,Yaobin Ding,Lina Wang,Yiyang Li,Jun He,Chengjun Wang
Water microdroplets are ubiquitous in atmospheric environment, where photo-irradiation and O 3 are available, while photo-decomposition of trace organic pollutants in microdroplets and the impact of atmospheric environmental factors on the photo-chemistry remain unclear. In this study, photochemical generation of reactive oxygen species and degradation of typical endocrine disturbing compounds (EDCs) in microdroplets were investigated under various atmospheric conditions (O 3 , inorganic anions and fulvic acid). The experimental results demonstrate that EDCs can be degraded in microdroplets, and the degradation efficiency is further improved under the stimulated solar irradiation. The degradation efficiency of estrone (E1), estradiol (E2), ethinyl estradiol (EE2), testosterone (T) exposing to sunlight irradiation is 55.45 %, 64.11 %, 89.72 %, and 24.72 %, respectively. The degradation of EDCs is attributed to the generation of hydroxyl and superoxide radicals at or near the microdroplets interface. In addition, with O 3 , the degradation efficiency of EDCs in microdroplets increased to 100 %, 100 %, 100 %, and 83.87 %, respectively. Common inorganic ions (Cl − , NO 3 − , SO 4 2− , and HCO 3 − ) and fulvic acid exhibit positive effects for degradation of EDCs at varying extents. Overall, these findings shed light on the generation of reactive oxygen species and degradation patthways of trace EDCs in microdroplets and improve the understanding of the effect associated with relevant environmental factors in atmospheric microdroplets.
研究领域:
环境科学
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生物学
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DOI
PubMed
高影响因子
Journal of Materials Chemistry A
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2025
·
IF 9.5
Xuyao Huo,Xinkun Chen,Zhen Cao,Xueye Chen
Due to the illegal discharge of organic wastewater, the amount of oil-containing water is increasing. Therefore, how to quickly and effectively carry out oil–water separation has become an urgent problem. Inspired by the gutter structure of ginkgo leaves and the conical structure of pine needles, we fabricated a bionic coupled cone-gradient groove (BCGG) using micro–nano precision 3D printing technology. Under the combined effect of Laplace pressure and capillary force, the surface can perform oil–water separation spontaneously, efficiently and rapidly, with the maximum transport speed reaching 55.2 mm s−1, which is approximately 11 times that of the traditional conical structure. The structure can perform anti-gravity transport of oil droplets in different environments such as gas phase, liquid phase and gas–liquid phase, while maintaining excellent transport performance for large volumes of oil droplets. This study has certain reference significance for microdroplet manipulation, liquid separation and transportation.
研究领域:
材料科学
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表面工程
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生物仿生学
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产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2020
·
IF 7.489
Xuan Li,Dong Feng,Lei Chen,Ding Weng,Chaolang Chen,Jiadao Wang
Hypothesis A binary mixture was used during injection with one water-miscible component and the other water-immiscible, which can help particles to migrate toward and then self-assemble at the interface. Experiments The ethanol-tetrachloromethane binary mixture was used to verify the self-assembly method, with the diameter of droplets being about 1 mm. As the ethanol diffused into the colloidal solution, the colloidal particles efficiently moved towards and self-assembled on the oil/water interface, while a colloidal particle film with high-coverage was able to rapidly form on the droplet surface even in an ultra-low concentration colloidal solution. The effects of ethanol concentration and particle concentration on self-assembly were investigated. Findings The driving force for self-assembly originated from the tension gradient generated by ethanol's concentration gradient at the particle/liquid interfaces, where the concentrations of ethanol and the colloidal solution had significant effects on self-assembly. The simulation and calculations results aligned well with experiments, providing the theoretical basis for this self-assembly method. Further, as-prepared magnetic particle-coated droplets transformed into a non-wetting soft solid, which had long lifetimes and could be precisely moved, coalesced, and transferred in various two-dimensional and three-dimensional liquid environments. Thus, wider applications are facilitated, such as droplet transfer, microreactor and other potential fields.
研究领域:
材料科学
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化学工程
·
界面科学
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产品关联
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Ziyue Zhang,Yi Ding,Xin Hua,Lingli Song,Songqin Liu
Photocatalysis and photo-Fenton oxidation are promising advanced oxidation technologies for water treatment. Nevertheless, their relatively slow kinetics largely limited their practical applications. Herein, we performed synergistic photocatalysis and photo-Fenton reactions in water microdroplets for the degradation of organic dyes. The efficiency of the microdroplet-based photoreactions was significantly improved with a degradation rate of 98.96% in microdroplets, while it was only 38.14% in the bulk solution. The enhanced degradation efficiency was due to the synergistic effect of the photocatalysis and photo-Fenton reactions in the microdroplets. First, the enrichment of both the dye (rhodamine B) and the catalyst (g-C3N4 nanosheets) at the aqueous interfaces enlarged the local surface concentration, playing a role in the reaction acceleration. Second, the spontaneously generated hydrogen peroxide (17.13 μM) at the aqueous interfaces triggered the photo-Fenton cycle and thus largely promoted the charge separation of g-C3N4 as well as the effective utilization of the photogenerated electrons and holes, leading to a significantly improved degradation efficiency of organic dyes. Further, we quantified the reaction kinetics of individual microdroplets in a real-time manner. The reaction constant in 10 μm microdroplets was 4.86 × 10–3 s–1, which was 22 times higher than that in the bulk phase (0.22 × 10–3 s–1). This study provided a better understanding of accelerated photoreactions at aqueous interfaces and a strategy for addressing the low efficiency of organic dye degradation.
研究领域:
环境科学
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化学工程
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DOI
PubMed
高影响因子
LAB ON A CHIP
·
2021
·Vol. 21
·期 11
·2217-2222
·
IF 6.799
Lingjun Zhang,Jianfeng Sun,Hong He,Yingzhou Huang,Haiyang Shi,Weigen Chen
The Raman detection of trace substances in complex oil is still a great challenge at present because of the strong disturbance of background activity and the suppression of intensity in spectra caused by complicated components. In this work, a simple and robust approach based on microdroplet liquid–liquid extraction for the real-time Raman spectroscopy monitoring of trace substances in complex oil is reported. Based on unbalanced chemical potentials between water and oil on a microfluidic chip, a target trace molecule is extracted from complex mineral oil to a water microdroplet. Benefiting from the real-time fluorescence intensities of fluorescein in a water microdroplet, the extraction performance is investigated and optimized. The optimal water microdroplet is implemented for the Raman detection of furfural in a complex mineral oil, a typical trace performance marker in electric power equipment, and this exhibits excellent sensitivity with a limit of detection (LOD) of 26 ppb. Compared to traditional detection technology for trace substances in complex oil (high performance liquid chromatography, HPLC), this method greatly simplified the process of measurement, reduced the volume of sample required, had a fast measurement time, and exhibited the prospect of real-time monitoring applications with high sensitivity, which not only promotes the development of oil quality but also enlarges existing knowledge related to using Raman spectroscopy in chem−/bio-sensing.
研究领域:
分析化学
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光谱学
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材料科学
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产品关联
DOI
PubMed
高影响因子
Journal of the Taiwan Institute of Chemical Engineers
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2020
·
IF 4.794
Haozhe Yi,Chunying Zhu,Taotao Fu,Youguang Ma
A cross-focused microchannel with symmetrical chamber is constructed to improve coalescence efficiency of droplets. The flow behavior of droplets and time scale are investigated experimentally. Results show that the flow patterns could be divided into four regimes: long droplet, multiple coalescence, double coalescence and non-coalescence. Moreover, the evolutions of deformation value and rotation angle of droplets are studied to understand the mechanism of droplets coalescence. Asynchronous coalescence could appear in this configuration on account of the existence of stagnancy time. The dimensionless liquid drainage time declines exponentially with the dimensionless velocity of continuous phase. The present configuration allows droplets to coalesce asynchronously, which greatly expands applicable operation region and accordingly facilitates the controllability of droplets coalescence.
研究领域:
流体力学
·
微流控技术
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产品关联
DOI
高影响因子
ACS Nano
·
2019
·
IF 13.903
Ying Wang,Liangjun Li,Huimin Liang,Yanlong Xing,Liting Yan,Pengcheng Dai,Xin Gu,Guoming Zhao,Xuebo Zhao
Understanding the crystallization pathway is of fundamental importance in controlling structures and functionalities for metal–organic frameworks (MOFs), but only few studies have been reported on the mechanism of crystallization for MOFs to date. Here, by using a microdroplet flow (MF) reaction technique, we successfully revealed the different status of HKUST-1 during its crystal growth process. The morphologies and structures of crystals at different stages were recorded and characterized by scanning electron microscopy, transmission electron microscopy, and small-angle X-ray diffraction. Experimental observations clearly demonstrate a process of crystallization by particle attachment (CPA) for crystal growth of HKUST-1 under MF conditions. The superstructure of HKUST-1, which is assembled from oriented attachment of nanosized particles of HKUST-1, is observed at early stage of crystal growth. This type of superstructure gradually transforms to true single crystals through a ripening effect upon increasing residence time, accompanied by increase in dimensions of crystals. Thus, the superstructure is the intermediate state during crystallization and acts as the bridge between disordered reactants and highly ordered single crystals. Based on these findings, the crystal growth of HKUST-1 in MF reaction can be elucidated as a process involving three steps: the generation of nanosized primary particles, the following assembly of the primary particles into a superstructure, and the ripening of superstructure into a crystal. Furthermore, the superstructure of HKUST-1 shows superior performance for CO2 and CH4 adsorptions. The CPA mechanism in the crystallization of HKUST-1 demonstrated in this work is in clear contrast to the monomer-by-monomer addition mechanism in classic models of crystal growth. This mechanism could have important reference meaning for understanding the crystal growth mechanism of other type of MOFs or other special morphologies.
研究领域:
材料科学
·
化学
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产品关联
DOI
PubMed
高影响因子
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