Highly Ordered Arrays of Femtoliter Surface Droplets

Rezk, Amgad R.; Yeo, Leslie; Zhang, Xuehua

doi:10.1002/smll.201501105

Cited by 76 publications

(102 citation statements)

References 32 publications

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“…Highly ordered droplet arrays are prepared by performing solvent exchange on chemically patterned substrates 19 where ethylene glycol dimethacrylate (EGDMA, 98%, Sigma-Aldrich) is used as oil liquid for forming droplets.…”

Section: Methodsmentioning

confidence: 99%

“…Recent advances in controlled droplet formation [17][18][19][20] had made it possible to produce femtoliter surface droplets arrays with controllable size, volume and location on a microchannell wall. By the solvent exchange process, we have been able to form highly ordered surface droplet arrays with designed spatial arrangement on prepatterned substrates.…”

Section: Introductionmentioning

confidence: 99%

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Flow-induced dissolution of femtoliter surface droplet arrays

et al. 2018

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The dissolution of liquid nanodroplets is a crucial step in many applied processes, such as separation and dispersion in the food industry, crystal formation of pharmaceutical products, concentrating and analysis in medical diagnosis, and drug delivery in aerosols. In this work, using both experiments and numerical simulations, we quantitatively study the dissolution dynamics of femtoliter surface droplets in a highly ordered array under a uniform flow. Our results show that the dissolution of femtoliter droplets strongly depends on their spatial positions relative to the flow direction, drop-to-drop spacing in the array, and the imposed flow rate. In some particular cases, the droplet at the edge of the array can dissolve about 30% faster than the ones located near the centre. The dissolution rate of the droplet increases by 60% as the inter-droplet spacing is increased from 2.5 μm to 20 μm. Moreover, the droplets close to the front of the flow commence to shrink earlier than those droplets in the center of the array. The average dissolution rate is faster for the faster flow. As a result, the dissolution time (Ti) decreases with the Reynolds number (Re) of the flow as Ti ∝ Re-3/4. The experimental results are in good agreement with the numerical simulations where the advection-diffusion equation for the concentration field is solved and the concentration gradient on the surface of the drop is computed. The findings suggest potential approaches to manipulate nanodroplet sizes in droplet arrays simply by dissolution controlled by an external flow. The obtained droplets with varying curvatures may serve as templates for generating multifocal microlenses in one array.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Flow-induced dissolution of femtoliter surface droplet arrays

et al. 2018

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“…2) The position, geometry, amount and size of the (micro)reservoir could be precisely adjusted and organized by intelligent and flexible design of the (super)wettability patterns (Figure b). For example, the volume of microdroplet had been reported to be as low as picoliter and femtoliter, and the geometry of the (micro)reservoir can be tuned for the synthesis of materials with specific shapes, such as hydrogel particles, biofilm microcluster, metal organic framework microsheet, and nanoparticle assembly . 3) (Micro)reservoirs can be spatially close to each other because droplet coalesce is avoided, which paves the way for miniaturization and point‐of‐care application of the SPW .…”

Section: Applicationsmentioning

confidence: 99%

Micro‐/Nanostructured Interface for Liquid Manipulation and Its Applications

Duan

Zheng

Zhao

et al. 2019

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Understanding the relationship between liquid manipulation and micro‐/nanostructured interfaces has gained much attention due to the wide potential applications in many fields, such as chemical and biomedical assays, environmental protection, industry, and even daily life. Much work has been done to construct various materials with interfacial liquid manipulation abilities, leading to a range of interesting applications. Herein, different fabrication methods from the top‐down approach to the bottom‐up approach and subsequent surface modifications of micro‐/nanostructured interfaces are first introduced. Then, interactions between the surface and liquid, including liquid wetting, liquid transportation, and a number of corresponding models, together with the definition of hydrophilic/hydrophobic, oleophilic/olephobic, the definition and mechanism of superwetting, including superhydrophobicity, superhydrophilicity, and superoleophobicity, are presented. The micro‐/nanostructured interface, with major applications in self‐cleaning, antifogging, anti‐icing, anticorrosion, drag‐reduction, oil–water separation, water collection, droplet (micro)array, and surface‐directed liquid transport, is summarized, and the mechanisms underlying each application are discussed. Finally, the remaining challenges and future perspectives in this area are included.

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“…Surface droplet arrays were prepared by solvent exchange on chemically patterned silicon wafer substrates. The experimental details for the preparation of pattern substrates, droplet formation, and growth on patterned substrates were provided in our previous work . After the first droplet arrays were converted into polymer lenses by polymerization, the substrates decorated with polymer microlens arrays were subjected to another solvent‐exchange process.…”

Section: Methodsmentioning

confidence: 99%

“…The experimental details for the preparation of pattern substrates, droplet formation, and growth on patterned substrates were provided in our previous work. [37,38] After the first droplet arrays were converted into polymer lenses by polymerization, the substrates decorated with polymer microlens arrays were subjected to another solvent-exchange process. The second layer of droplets preferred to nucleate and grow from the edge of the first layer,a nd the asymmetric droplets on lenses morphology was obtained after solvent exchange.…”

Section: Fabricationofasymmetric Superhydrophobic Surfacesmentioning

confidence: 99%

Simple Nanodroplet Templating of Functional Surfaces with Tailored Wettability and Microstructures

Peng

Zhang

2017

Chemistry An Asian Journal

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Recently,s olvente xchange has been demonstrated as as imple solution-based approachf or the controlled formation of surface nanodroplets over large areas. The asformed surfacen anodroplets provide new opportunities for aw ide range of droplet-based applications. Herein,i ti s demonstrated that surface nanodroplets can be used as versatile structural templates for the fabrication of functional surfaces with tailored wettability and morphology. Guided by the microstructural and wetting properties of desert beetle'sb ack and cactuss pine, two types of functional surfaces have been prepared. The first biomimetic surfaceo fdesert beetle's back, with hydrophilic lumps on ah ydrophobic background, was obtained by independents electives urface modification of polymerizeds urface nanodropletsa nd the background surface. The second surface, with anisotropic wettingm icrostructures, was fabricated by controlled deposition of droplets on the rim of polymer lenses. The results showeds ystematic improvement of wettability and efficiency of water collection by using the as-prepared biomimetic surfaces, compared with substrates withoutt he designed microstructures.T his work demonstrates surface nanodroplets as an ew type of template in the design and preparation of functional surfaces with controlled wettability and morphology.

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Highly Ordered Arrays of Femtoliter Surface Droplets

Cited by 76 publications

References 32 publications

Flow-induced dissolution of femtoliter surface droplet arrays

Flow-induced dissolution of femtoliter surface droplet arrays

Micro‐/Nanostructured Interface for Liquid Manipulation and Its Applications

Simple Nanodroplet Templating of Functional Surfaces with Tailored Wettability and Microstructures

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