Droplet Pub Date : 2025-03-08 DOI: 10.1002/dro2.70000

Yufei Wu, Wenhai Xu, Pengpeng Xie, Linfeng Yu, Zhaowang Dan, Wenyu An, Liang Luo, Xiaoming Sun

{"title":"Growth kinetics of electrochemically generated hydrogen bubbles at increased pressures","authors":"Yufei Wu, Wenhai Xu, Pengpeng Xie, Linfeng Yu, Zhaowang Dan, Wenyu An, Liang Luo, Xiaoming Sun","doi":"10.1002/dro2.70000","DOIUrl":"https://doi.org/10.1002/dro2.70000","url":null,"abstract":"Bubble growth kinetics has been attracting vast attention in water electrolysis and other gas evolution reactions, but mostly investigated under ambient pressure. For practical scenarios, bubble evolution is usually carried out under high pressure. To better understand the bubble growth kinetics, we monitored the hydrogen bubble evolution process at increased pressures during electrochemical hydrogen production. Unlike the common sense that high pressures could result in smaller bubble size, our results revealed that the increased pressure would increase the aerophilicity of electrode surface, with decreased bubble contact angle from 111° to 89° for 0.1‒2.0 MPa, increased detachment size from 233 to 1207 µm, and reduced growth coefficient from 230 to 10.9 for the high pressures from 0.1 to 3.0 MPa. The steady high-pressure bubble growth kinetics are basically governed by the as-formed supersaturation in bulk solution, which is the balance between the driving force (current density) and the enlarged solubility of bulk solution under high pressure. Insufficient driving force would induce the depletion of bulk supersaturation and stagnate the bubble growth. Further investigation on high-pressure bubble evolution behaviors should shed light on practical industrial electrode design with extended usage life.","PeriodicalId":100381,"journal":{"name":"Droplet","volume":"4 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dro2.70000","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865962","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

Liquid directional transport surface applied to the spacecraft fluid management system: Fundamentals and prospect analysis 液体定向输运面在航天器流体管理系统中的应用：基础与前景分析

Droplet Pub Date : 2025-03-05 DOI: 10.1002/dro2.165

Yifan He, Wenshuai Xu, Kuo Yan, Lingling Zhao, Jun Wang, Kai Li, Jingyuan Liu, Heng Jiang

{"title":"Liquid directional transport surface applied to the spacecraft fluid management system: Fundamentals and prospect analysis","authors":"Yifan He, Wenshuai Xu, Kuo Yan, Lingling Zhao, Jun Wang, Kai Li, Jingyuan Liu, Heng Jiang","doi":"10.1002/dro2.165","DOIUrl":"https://doi.org/10.1002/dro2.165","url":null,"abstract":"Liquid directional transport surfaces have the ability to control the movement of liquids in specific directions, making them highly applicable in various fields such as heat transfer, fluid management, microfluidics, and chemical engineering. This review aims to summarize the research progress on liquid directional transport surfaces and spacecraft fluid management devices. Among the different liquid control technologies available, certain surface design methods based on principles of fluid dynamics under microgravity show remarkable potential for space fluid management. Precise fluid management is crucial for the in-orbit operation of spacecraft. Utilizing surface tension effects represents the most direct and effective approach to achieve directional liquid transport in space. The intrinsic flow characteristics of the two-dimensional plane of directional transport surfaces are advantageous for managing fluids in the confined spaces of spacecraft. By analyzing the functional characteristics of these liquid directional transport surfaces, we assess their feasibility for integration into spacecraft fluid management devices. Considering the features of the space environment, this review also provides design guidelines for liquid directional transport surfaces suitable for use in spacecraft fluid management devices, serving as a significant reference for future research.","PeriodicalId":100381,"journal":{"name":"Droplet","volume":"4 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dro2.165","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865912","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

Advancements in liquid marbles as an open microfluidic platform: Rapid formation, robust manipulation, and revolutionary applications 液体弹珠作为开放微流控平台的进展：快速形成、稳健操作和革命性应用

Droplet Pub Date : 2025-02-18 DOI: 10.1002/dro2.160

Tong Tong, Huaiqing Hu, Yuanhao Xie, Jing Jin

{"title":"Advancements in liquid marbles as an open microfluidic platform: Rapid formation, robust manipulation, and revolutionary applications","authors":"Tong Tong, Huaiqing Hu, Yuanhao Xie, Jing Jin","doi":"10.1002/dro2.160","DOIUrl":"https://doi.org/10.1002/dro2.160","url":null,"abstract":"Liquid marbles (LMs) have become a focal point in microfluidics for their efficient manipulation of small liquid volumes. These non-wetting droplets, typically coated with hydrophobic particles, offer enhanced stability, reduced evaporation and diverse utility, distinguishing them from bare droplets. This review examines advancements in LMs from 2014 to 2024, focusing on their rapid formation, robust manipulation, and revolutionary applications—termed the “3R trilogy.” We delve into the generation mechanisms, analyzing laboratory and engineering production techniques, and explore how surface particles affect LMs’ physicochemical properties. The structural dynamics and motion control of LMs are investigated, detailing their response to external forces and environmental factors. The review also highlights the state-of-the-art applications of LMs in digital microfluidics, biochemical analysis, materials synthesis, environmental monitoring, soft robotics, and energy harvesting. Concluding with a discussion on significant progress and future development trends, this review provides insights and ideas for broader applications of LM-based microfluidic platforms.","PeriodicalId":100381,"journal":{"name":"Droplet","volume":"4 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dro2.160","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865837","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

Advances in networking droplets 液滴网络研究进展

Droplet Pub Date : 2025-02-18 DOI: 10.1002/dro2.173

Zhejun Chong, Yi Zeng, Youlong Kang, Ke Ding, Xin Du, Zhongze Gu

引用次数: 0

Fog collection with hairy wires 雾收集与毛茸茸的电线

Droplet Pub Date : 2025-02-17 DOI: 10.1002/dro2.166

Leyun Feng, Wonjae Choi, Kyoo-Chul Park

{"title":"Fog collection with hairy wires","authors":"Leyun Feng, Wonjae Choi, Kyoo-Chul Park","doi":"10.1002/dro2.166","DOIUrl":"https://doi.org/10.1002/dro2.166","url":null,"abstract":"Fog collection can be an affordable, practical solution to water scarcity in many regions around the world. Commercial fog harvesters typically use mesh structures composed of cylindrical wires or thin strips. The choice of their length scale, especially the width, has been a challenge due to a trade-off problem—wide wires or strips cause fog droplets to avoid contact and display lower deposition efficiency, while meshes comprising thin cylinders or strips often suffer from clogging and exhibit low drainage efficiency. In this study, we propose a cost-effective dual-scale structure, a vertical core composed of two twisted cylindrical wires surrounded by thin hairs protruding along radial direction, which can greatly improve the water collection efficiency by decoupling the mechanisms for droplet deposition and drain: while thin hairs allow fog droplets to retain high Stokes number and deposit with high efficiency, a vertical core functions as a wicking mechanism for deposited droplets to drain quickly. Fabricated hairy wires have a water collection rate of more than two and a half times that of smooth cylindrical wires of the same diameter, and their steady-state performance does not suffer from clogging, in contrast to conventional meshes composed of thin wires. Proposed hairy wires can be mass-produced by slightly modifying commercial products. This study provides a practical solution for the optimal design of fog collectors, benefiting the fight against the global water crisis.","PeriodicalId":100381,"journal":{"name":"Droplet","volume":"4 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dro2.166","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865772","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

Frontispiece, Volume 4, Number 1, January 2025 封面，第四卷，第1期，2025年1月

Droplet Pub Date : 2025-01-23 DOI: 10.1002/dro2.171

Jie Zhang, Hao Yang, Jiannan Cai, Junhao Shi, Yuquan Zheng, Hamed Rajabi, Jieliang Zhao, Jianing Wu

引用次数: 0

Front Cover, Volume 4, Number 1, January 2025 封面，第四卷，第1期，2025年1月

Droplet Pub Date : 2025-01-23 DOI: 10.1002/dro2.167

Negar Danesh, Matin Torabinia, Hyejin Moon

引用次数: 0

Back Cover, Volume 4, Number 1, January 2025 封底，第四卷，第1期，2025年1月

Droplet Pub Date : 2025-01-23 DOI: 10.1002/dro2.168

Daniel O. Reddy, Lishen Zhang, Thomas R. Covey, Richard D. Oleschuk