Droplet Pub Date : 2023-08-28 DOI: 10.1002/dro2.89

Rutvik Lathia, Chandantaru D. Modak, Prosenjit Sen

{"title":"Two modes of contact-time reduction in the impact of particle-coated droplets on superhydrophobic surfaces","authors":"Rutvik Lathia, Chandantaru D. Modak, Prosenjit Sen","doi":"10.1002/dro2.89","DOIUrl":"https://doi.org/10.1002/dro2.89","url":null,"abstract":"Reducing the contact time during droplet impact is essential for many scientific and industrial applications, such as self-cleaning, anti-icing, heat transfer, and condensation. This paper reports contact-time reduction by coating droplets with micro–nano hydrophobic particles. Such particle-coated droplets are known as liquid marbles (LM). LM impact on superhydrophobic surfaces reveals two different modes of contact-time reduction. For lower impact energies, the reduced adhesion of LM with the surface is responsible for a reduction of up to 21%. Contact-time reduction in this regime is found to be independent of particle size but dependent on the solid fraction of LM. However, a fragmentation-based contact-time reduction is observed for larger particle sizes and higher impact energies. Here, the reduction is as high as 65%. Such fragmentation occurs because the spreading LM lamella breaks when its thickness becomes similar to particle dimensions. Our findings reveal the potential of LM as a novel approach to reduce contact time during droplet impact, with implications for various scientific and industrial applications.","PeriodicalId":100381,"journal":{"name":"Droplet","volume":"2 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dro2.89","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50146208","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: 1

Hydrophilic solvent recovery from switched-on microdroplet dissolution 从开启的微滴溶解中回收亲水溶剂

Droplet Pub Date : 2023-08-28 DOI: 10.1002/dro2.82

Romain Billet, Binglin Zeng, Hongyan Wu, James Lockhart, Mike Gattrell, Hongying Zhao, Xuehua Zhang

{"title":"Hydrophilic solvent recovery from switched-on microdroplet dissolution","authors":"Romain Billet, Binglin Zeng, Hongyan Wu, James Lockhart, Mike Gattrell, Hongying Zhao, Xuehua Zhang","doi":"10.1002/dro2.82","DOIUrl":"https://doi.org/10.1002/dro2.82","url":null,"abstract":"Switchable hydrophilicity solvents (SHSs) are a unique class of chemical compounds that can be switched between their hydrophobic and hydrophilic forms. The switchable characteristics allow SHSs to be used as emerging, green solvents for sustainable extraction and separation technology. In the production of polymeric microparticles from recycled plastics, SHSs are used to dissolve the polymer and then are switched to the hydrophilic form for separation from the generated polymeric microparticles. However, it is extremely difficult to fully recover the SHS residue from the mixtures. In this work, we will identify the key parameters that determine the level of the solvent residue during the switched-on dissolution of emulsion microdroplets. The SHS N,N-dimethylcyclohexylamine from solvent–polymer binary emulsion droplets was switched to the hydrophilic, water-soluble form, triggered by addition of an acid in the surrounding aqueous phase. By applying a sensitive detection method developed in this work, we compared the levels of SHS residue in polymer microparticles obtained under 30 different dynamical and chemical conditions for the switching processes. The quantitative analysis revealed that residue levels remained constant at varied addition rates and concentration of the trigger solution, but decreased with the increase in organic phase fractions or the decrease in the emulsion temperature. Trapped water in the drops during switched-on dissolution may have contributed to the high level of solvent residue. The understanding of the new possible mechanism for residual solvent reported in this work may help develop effective approaches for the recovery of switchable solvents in environmentally friendly separation processes.","PeriodicalId":100381,"journal":{"name":"Droplet","volume":"2 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dro2.82","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50146207","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: 1

Material assembly by droplet drying: From mechanics theories to applications 液滴干燥组装材料：从力学理论到应用

Droplet Pub Date : 2023-08-08 DOI: 10.1002/dro2.76

Ziyu Chen, Kangyi Peng, Baoxing Xu

{"title":"Material assembly by droplet drying: From mechanics theories to applications","authors":"Ziyu Chen, Kangyi Peng, Baoxing Xu","doi":"10.1002/dro2.76","DOIUrl":"https://doi.org/10.1002/dro2.76","url":null,"abstract":"Evaporation of droplets composed of insoluble materials provides a low-cost and facile route for assembling materials and structures in a wide spectrum of functionalities down to the nanoscale and also serves as a basis for innovating ink-solution-based future manufacturing technologies. This review summarizes the fundamental mechanics theories of material assembly by droplet drying both on solid and liquid substrates and in a fully suspended air environment. The evolution of assembly patterns, material deformation, and liquid flow during droplet drying and its response to external stimuli ranging from solution surfactant and pH value, surface geometric pattern and wettability, drying temperature, pressure environment, to electrical field have been highlighted to elucidate the coupling mechanisms between solid materials and liquid solutions and the manipulation strategies for material assembly through an either active or passive means. The recent progresses in ink-based printing technologies with selected examples are also presented to illustrate the immediate applications of droplet drying, with a focus on printing electronic sensors and biomedical devices. The remaining challenges and emerging opportunities are discussed.","PeriodicalId":100381,"journal":{"name":"Droplet","volume":"2 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dro2.76","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50124487","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

Identification of metal–air batteries from water energy harvesters 从水能采集器中鉴定金属-空气电池

Droplet Pub Date : 2023-08-08 DOI: 10.1002/dro2.80

Xiaote Xu, Xiaodan Yang, Zhuomin Zhang, Ying Hong, Shiyuan Liu, Yao Shan, Zehua Peng, Siyuan Wang, Xi Yao, Zhengbao Yang

引用次数: 1

Hydrovoltaic energy from water droplets: Device configurations, mechanisms, and applications 来自水滴的光伏能量：设备配置、机制和应用

Droplet Pub Date : 2023-08-01 DOI: 10.1002/dro2.77

Luxian Li, Xiang Wang, Wei Deng, Jun Yin, Xuemei Li, Wanlin Guo

引用次数: 0

Antitangling and manufacturable Fog Harps for high-efficiency water harvesting 防倾斜和可制造的雾耙，用于高效集水

Droplet Pub Date : 2023-08-01 DOI: 10.1002/dro2.78

Jimmy K. Kaindu, Kevin R. Murphy, Nicholas G. Kowalski, Alexandra N. Jones, Matthew Davis Fleming, Brook S. Kennedy, Jonathan B. Boreyko

{"title":"Antitangling and manufacturable Fog Harps for high-efficiency water harvesting","authors":"Jimmy K. Kaindu, Kevin R. Murphy, Nicholas G. Kowalski, Alexandra N. Jones, Matthew Davis Fleming, Brook S. Kennedy, Jonathan B. Boreyko","doi":"10.1002/dro2.78","DOIUrl":"https://doi.org/10.1002/dro2.78","url":null,"abstract":"Fog Harps harvest substantially more water than conventional mesh-based harvesters. However, to date, all large-scale Fog Harps have been impractically hand-wound at low wire tensions and suffer from elastocapillary wire tangling. Here, we develop large-scale and high-tension Fog Harps that are manufacturable and antitangling. These Fog Harps retain the record-setting fog harvesting efficiency (<math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>η</mi>\u0000 <mo>≈</mo>\u0000 <mn>17</mn>\u0000 </mrow>\u0000 <annotation> $eta approx 17$</annotation>\u0000 </semantics></math>%) of their optimized scale-model counterparts, while uniquely enabling practical real-life implementation. Manufacturability was achieved by adapting the industrial process for making harp screens, a pre-existing technology used for screening solid materials. The critical tension required to minimize wire tangling was rationalized by an improved elastocapillary tangling model.","PeriodicalId":100381,"journal":{"name":"Droplet","volume":"2 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dro2.78","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50115462","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: 2

Front Cover, Volume 2, Number 3, July 2023 封面，第2卷，第3期，2023年7月

Droplet Pub Date : 2023-07-25 DOI: 10.1002/dro2.83

Duokui Fang, Wenhao Zhou, Yuankai Jin, Xiaofeng Liu, Yubin Zeng, Zuankai Wang, Huai Zheng

引用次数: 0

Back Cover, Volume 2, Number 3, July 2023 封底，第2卷，第3期，2023年7月

Droplet Pub Date : 2023-07-25 DOI: 10.1002/dro2.84

Izumi Hashimoto, Toshihisa Osaki, Hirotaka Sugiura, Hisatoshi Mimura, Sho Takamori, Norihisa Miki, Shoji Takeuchi

引用次数: 0

Frontispiece, Volume 2, Number 3, July 2023 Frontispiece，第2卷，第3期，2023年7月

Droplet Pub Date : 2023-07-25 DOI: 10.1002/dro2.87

Wei Fang, Shun Wang, Hu Duan, Shahid Ali Tahir, Kaixuan Zhang, Lixia Wang, Xi-Qiao Feng, Meirong Song