IF 9.1

Droplet Pub Date : 2026-01-01 DOI: 10.1002/dro2.70034

Sixiang Rao, Weiliang Zhi, Chengkai Hong, Yanan Du, Long Chen, Yuan Luo, Yifan Liu

{"title":"High-throughput generation of aqueous two-phase microcapsules using microfluidic bubble triggering","authors":"Sixiang Rao, Weiliang Zhi, Chengkai Hong, Yanan Du, Long Chen, Yuan Luo, Yifan Liu","doi":"10.1002/dro2.70034","DOIUrl":"https://doi.org/10.1002/dro2.70034","url":null,"abstract":"Hydrogel microcapsules are powerful microreactor vessels that have attracted widespread attention and research. Among the various methods for their generation, the aqueous two-phase system (ATPS) is by far the most straightforward approach. However, the high viscosity of ATPS solutions significantly limits the generation throughput of hydrogel microcapsule. In this study, we developed a novel high-throughput approach for generating hydrogel microcapsules using a microfluidic bubble-triggering strategy. By integrating constant-pressure air flow with droplet microfluidics devices, we efficiently manipulated the formation of ATPS droplet through bubble-induced Rayleigh-Plateau instability, enabling the production of uniform, monodisperse microcapsules. Additionally, the droplet generation frequency in the bubble-triggering method exceeded 36 kHz. We further demonstrated the encapsulation of genetically engineered Escherichia coli strains, which acted as biosensors for arsenic ions and caprolactam, highlighting the potential of these microcapsules for biosensing applications. This advancement in hydrogel microcapsule generation offers promising implications for scalable applications in biosensing, organoid culture, and high-throughput screening.","PeriodicalId":100381,"journal":{"name":"Droplet","volume":"5 1","pages":""},"PeriodicalIF":9.1,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dro2.70034","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146016222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Dielectrowetting of sessile droplets of smectic liquid crystals 近晶液晶中无根液滴的介电润湿

IF 9.1

Droplet Pub Date : 2026-01-01 DOI: 10.1002/dro2.70037

Filippo Marinello, Giovanni Bexon, Davide Ferraro, Matteo Pierno, Bruno Zappone, Giampaolo Mistura

{"title":"Dielectrowetting of sessile droplets of smectic liquid crystals","authors":"Filippo Marinello, Giovanni Bexon, Davide Ferraro, Matteo Pierno, Bruno Zappone, Giampaolo Mistura","doi":"10.1002/dro2.70037","DOIUrl":"https://doi.org/10.1002/dro2.70037","url":null,"abstract":"We report on the dielectrowetting of sessile droplets of two common liquid crystals, 4-cyano-4′-pentylbiphenyl (5CB) and 4-cyano-4′-n-octylbiphenyl (8CB), deposited on interdigitated electrodes that were treated to induce homeotropic anchoring. We found a pronounced hysteretic response of the contact angle to the applied voltage caused by the pinning and depinning of the droplet contact line. Depinning occurred as the voltage exceeded a threshold value that increased from the nematic to the isotropic phase, whereas the smectic phase showed an intermediate value. Above the threshold, the contact angle decreased linearly and rapidly as a function of the voltage square, as expected from the dielectrowetting equation originally formulated for dielectric and isotropic liquids, with a slope larger in the anisotropic liquid crystal phases than in the isotropic phase. Observation between crossed polarizers showed that the molecular director realigned along the applied field in the anisotropic phase near the surface between the electrodes, thereby increasing the effective dielectric constant and strengthening the dielectrophoretic force compared to the isotropic phase. Director realignment involved the nucleation of topological defects in the nematic phase and was inhibited by large energy barriers in the smectic phase, which weakened the dielectrowetting response.","PeriodicalId":100381,"journal":{"name":"Droplet","volume":"5 1","pages":""},"PeriodicalIF":9.1,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dro2.70037","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146016225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Energy harvesting meets superhydrophobic surfaces: Recent advances 能量收集与超疏水表面：最新进展

IF 9.1

Droplet Pub Date : 2026-01-01 DOI: 10.1002/dro2.70035

Leiyang Wang, Ye Zhao, Jinteng Hu, Shah Fahad, Hao Wu

{"title":"Energy harvesting meets superhydrophobic surfaces: Recent advances","authors":"Leiyang Wang, Ye Zhao, Jinteng Hu, Shah Fahad, Hao Wu","doi":"10.1002/dro2.70035","DOIUrl":"https://doi.org/10.1002/dro2.70035","url":null,"abstract":"Ambient energy harvesting from various renewable sources, including solar, thermal, wave, droplet, wind, and biomechanical energy, presents a promising solution for sustainable power generation and battery-free Internet of Things networks. However, these technologies face significant challenges in energy conversion efficiency and device durability due to environmental factors such as surface contamination, moisture accumulation, and biofouling. Superhydrophobic surfaces address these limitations through their unique properties of self-cleaning, water-repellent, and anti-bacterial, significantly enhancing energy harvesting performance and reliability. This review systematically summarizes recent advances in superhydrophobic surface-enhanced energy harvesting devices based on various mechanisms, including photovoltaics, electromagnetism, piezoelectricity, triboelectricity, thermoelectricity, and electrical double-layer dynamics. We first provide an updated overview of superhydrophobic surfaces, including their design strategies and fabrication methods. Then, we offer a comprehensive summary of their role in optimizing various energy harvesting devices. Finally, we discuss prospective challenges, potential solutions, and recommendations for future developments within this emerging interdisciplinary field.","PeriodicalId":100381,"journal":{"name":"Droplet","volume":"5 1","pages":""},"PeriodicalIF":9.1,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dro2.70035","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146016224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Correction to “Biomimetic chloroplasts: Two-phase microfluidic platforms with selective permeability for artificial photosynthesis” 对“仿生叶绿体：用于人工光合作用的具有选择性渗透性的两相微流控平台”的更正

IF 9.1

Droplet Pub Date : 2025-12-30 DOI: 10.1002/dro2.70051

引用次数: 0

When contact lines remember: Surface charge and the evolving interaction with defects 当接触线记住：表面电荷和演变的相互作用与缺陷

IF 9.1

Droplet Pub Date : 2025-12-07 DOI: 10.1002/dro2.70039

Yaolei Xiang, Benedikt Straub, Diego Cortes, Hans-Jürgen Butt, Kaloian Koynov

{"title":"When contact lines remember: Surface charge and the evolving interaction with defects","authors":"Yaolei Xiang, Benedikt Straub, Diego Cortes, Hans-Jürgen Butt, Kaloian Koynov","doi":"10.1002/dro2.70039","DOIUrl":"https://doi.org/10.1002/dro2.70039","url":null,"abstract":"The motion of contact line plays a crucial role in both natural phenomena and industrial processes. While it is well known that surface defects influence contact line dynamics, we demonstrate that their impact depends not only on geometry, size, and composition, but also on the history of fluid interaction with the surface. Using ultrafast, high-resolution reflection microscopy, we visualized the dynamics of the three-phase contact line as successive water droplets slid across a hydrophobic surface patterned with protrusions. We observed a growing attraction between the contact line and surface defects with increasing drop number. This effect arises from the spontaneous electrification that occurs during sliding: the droplets and the surface acquire opposite charges, generating electrostatic forces that significantly influence both advancing and receding contact lines. These forces contribute more than half of the total pinning force. Our findings reveal a previously overlooked factor in drop sliding and offer new insights into the dynamics of the contact line.","PeriodicalId":100381,"journal":{"name":"Droplet","volume":"5 1","pages":""},"PeriodicalIF":9.1,"publicationDate":"2025-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dro2.70039","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146027544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Inside Front Cover, Volume 4, Number 4, October 2025 封面内页，第四卷，第4期，2025年10月

IF 9.1

Droplet Pub Date : 2025-10-29 DOI: 10.1002/dro2.70043

Jiaxing Shen, Yaerim Lee, Junichiro Shiomi

引用次数: 0

Inside Back Cover, Volume 4, Number 4, October 2025 封底内，第四卷，第4期，2025年10月

IF 9.1

Droplet Pub Date : 2025-10-29 DOI: 10.1002/dro2.70042

Qining Leo Wang, Penghao Tian, Chang-Jin “CJ” Kim

引用次数: 0

Back Cover, Volume 4, Number 4, October 2025 封底，第四卷，第4期，2025年10月

IF 9.1

Droplet Pub Date : 2025-10-29 DOI: 10.1002/dro2.70041

Hangjian Ling, Isaac Rodriguez, Foram S. Fanasia, Paitynn Boutin

引用次数: 0

Front Cover, Volume 4, Number 4, October 2025 封面，第四卷，第4期，2025年10月

IF 9.1

Droplet Pub Date : 2025-10-29 DOI: 10.1002/dro2.70044

Mengjie Song, Runmiao Gao, Chaobin Dang, Keke Shao, Long Zhang

引用次数: 0

Surfactant-mediated electro-dewetting of droplets in oil for liquid-shape manipulation 表面活性剂介导的油中液滴的电脱湿操作

IF 9.1

Droplet Pub Date : 2025-09-29 DOI: 10.1002/dro2.70033

Qining Leo Wang, Penghao Tian, Chang-Jin “CJ” Kim

{"title":"Surfactant-mediated electro-dewetting of droplets in oil for liquid-shape manipulation","authors":"Qining Leo Wang, Penghao Tian, Chang-Jin “CJ” Kim","doi":"10.1002/dro2.70033","DOIUrl":"https://doi.org/10.1002/dro2.70033","url":null,"abstract":"The capability to manipulate liquid shape at the microscale has enabled numerous microfluidic devices. Due to its simple electric actuation, electrowetting-on-dielectric has been widely used in a variety of microfluidic applications that require reversible liquid-shape modulation. However, its use of dielectric and hydrophobic layers raised operation voltage, caused reliability issues, and increased fabrication cost. As an alternative mechanism, ionic-surfactant-mediated electro-dewetting has recently been demonstrated to enable digital microfluidics in air with a much lower voltage, higher reliability, and simpler chip fabrication. However, electro-dewetting for liquid-shape manipulation has remained poorly explored due to its limited contact-angle changes. Here, we investigated electro-dewetting in oil by testing various droplet liquids and hydrophilic substrate materials. To guide device development, cationic surfactants with varying hydrocarbon chain lengths and concentrations are tested. A contact-angle change of 100° is obtained for electro-dewetting of a dimethyl sulfoxide droplet in hexadecane with mere 4 V. To evaluate the utility of electro-dewetting in oil, proof-of-concept devices are assembled to explore the potential in optical applications such as reflective displays and liquid lenses. Compatible with various liquids and substrates, electro-dewetting with the liquid-in-oil configuration opens a door for simpler and more reliable microfluidic devices.","PeriodicalId":100381,"journal":{"name":"Droplet","volume":"4 4","pages":""},"PeriodicalIF":9.1,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dro2.70033","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145385144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

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