Droplet最新文献

{"title":"Collective wetting transitions of submerged gas-entrapping microtextured surfaces","authors":"Sankara Arunachalam,&nbsp;Himanshu Mishra","doi":"10.1002/dro2.135","DOIUrl":"10.1002/dro2.135","url":null,"abstract":"<p>Numerous natural and industrial processes entail the spontaneous entrapment of gas/air as rough/patterned surfaces are submerged under water. As the wetting transitions ensue, the gas diffuses into the water leading to the fully water-filled state. However, the standard models for wetting do not account for the microtexture's topography on collective wetting transitions. In other words, it is not clear whether the lifetime of <i>n</i> cavities arranged in a one-dimensional (I-D) line or a two-dimensional (II-D) (circular or square) lattice would be the same or not as a single 0-D cavity. In response, we tracked the time-dependent fates of gas pockets trapped in I-D and II-D lattices and compared them with wetting transitions in commensurate 0-D cavities. Interestingly, the collective wetting transitions in the I-D and the II-D arrays had a directionality such that the gas from the outermost cavities was lost the first, while the innermost got filled by water the last. In essence, microtexture's spatial organization afforded shielding to the loss of the gas from the innermost cavities, which we probed as a function of the microtexture's pitch, surface density, dimensionality, and hydrostatic pressure. These findings advance our knowledge of wetting transitions in microtextures and inspiring surface textures to protect electronic devices against liquid ingression.</p>","PeriodicalId":100381,"journal":{"name":"Droplet","volume":"3 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dro2.135","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141267501","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}

{"title":"Inertial mixing of acoustically levitated droplets for time-lapse protein crystallography","authors":"Soichiro Tsujino,&nbsp;Yohei Sato,&nbsp;Shichao Jia,&nbsp;Michal W. Kepa,&nbsp;Sofia Trampari,&nbsp;Takashi Tomizaki","doi":"10.1002/dro2.132","DOIUrl":"https://doi.org/10.1002/dro2.132","url":null,"abstract":"<p>Varying the chemical consistency of acoustically levitated droplets opens up an in situ study of chemical and biochemical reactions in small volumes. However, the optimization of the mixing time and the minimization of the positional instability induced by solution dispensing are necessary for practical applications such as the study of the transient state of macromolecules crystallography during the ligand binding processes. For this purpose, we study the inertial mixing in a configuration compatible with the room-temperature crystallography using the acoustic levitation diffractometer, therein solution drops ejected at high velocity collide and coalesce with droplets dispensed on acoustically levitated and rotating polymer thin-film sample holders. With the proposed method, we are able to achieve the mixing time of ∼0.1 s for sub-micro and a few microliter droplets. The observed short mixing time is ascribed to the rapid penetration of the solution into the droplets and confirmed by a computational fluid dynamic simulation. The demonstrated accelerated solution mixing is tested in a pilot time-lapse protein crystallography experiment using the acoustic levitation diffractometer. The results indicate the detection of transient ligand binding state within 2 s after the solution dispensing, suggesting the feasibility of the proposed method for studying slow biochemical processes.</p>","PeriodicalId":100381,"journal":{"name":"Droplet","volume":"3 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dro2.132","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141967638","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}

{"title":"Quantitative liquid storage by billiards-like droplet collision on surfaces with patterned wettability","authors":"Minghao Li,&nbsp;Haoxu Yu,&nbsp;Zhirui Liu,&nbsp;Ziyue Gao,&nbsp;Faze Chen","doi":"10.1002/dro2.125","DOIUrl":"https://doi.org/10.1002/dro2.125","url":null,"abstract":"<p>There has been significant interest in researching droplet transport behavior on composite wetting surfaces. However, current research is primarily focused on modifying individual droplets and lacks an in-depth investigation into high-precision droplet storage. This study introduces a “billiard ball” droplet transport and storage platform (TSP) with differentiated areas. Within this platform, the volume of droplets stored in the area reaches a consistent threshold through droplet “scrambling,” inspired by the water-gathering behavior of spiders. The TSP involves connecting two regions of different sizes using a three-dimensional stepped wedge angle structure. However, this connection is not seamless, leaving a 2-mm gap between the regions. This gap is intentionally designed to enable continuous droplet transfer while preventing any static migration. Through systematic experimental and simulation analysis, we investigated the influence of superhydrophilic pattern structures and parameters on quantitative droplet storage. We established a functional relationship between the pattern area and the stored volume, and analyzed the intrinsic mechanism of droplet collision separation. This enabled us to achieve on-demand quantitative droplet storage and autonomize the storage process. The “billiard ball” droplet transport–storage platform proposed in this study holds promising applications in the fields of biomedical and organic chemistry.</p>","PeriodicalId":100381,"journal":{"name":"Droplet","volume":"3 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dro2.125","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141967639","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}

{"title":"Heat transfer during droplet impact on a cold superhydrophobic surface via interfacial thermal mapping","authors":"Vijay Kumar,&nbsp;Qianxi Fu,&nbsp;Harrison Szeto,&nbsp;Yangying Zhu","doi":"10.1002/dro2.124","DOIUrl":"https://doi.org/10.1002/dro2.124","url":null,"abstract":"<p>Undesired heat transfer during droplet impact on cold surfaces can lead to ice formation and damage to renewable infrastructure, among others. To address this, superhydrophobic surfaces aim to minimize the droplet surface interaction thereby, holding promise to greatly limit heat transfer. However, the droplet impact on such surfaces spans only a few milliseconds making it difficult to quantify the heat exchange at the droplet–solid interface. Here, we employ high-speed infrared thermography and a three-dimensional transient heat conduction COMSOL model to map the dynamic heat flux distribution during droplet impact on a cold superhydrophobic surface. The comprehensive droplet impact experiments for varying surface temperature, droplet size, and impacting height reveal that the heat transfer effectiveness (<span></span><math>\u0000 <semantics>\u0000 <msup>\u0000 <mi>Q</mi>\u0000 <mo>′</mo>\u0000 </msup>\u0000 <annotation>$Q^{prime}$</annotation>\u0000 </semantics></math>) scales with the dimensionless maximum spreading radius as <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>Q</mi>\u0000 <mo>′</mo>\u0000 </msup>\u0000 <mo>∼</mo>\u0000 <msup>\u0000 <mrow>\u0000 <mo>(</mo>\u0000 <msub>\u0000 <mi>R</mi>\u0000 <mi>max</mi>\u0000 </msub>\u0000 <mo>/</mo>\u0000 <msub>\u0000 <mi>R</mi>\u0000 <mi>i</mi>\u0000 </msub>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <mn>1.6</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>${Q}^{prime}sim ({R}_{max}/{R}_{i})^{1.6}$</annotation>\u0000 </semantics></math>, deviating from previous semi-infinite scaling. Interestingly, despite shorter contact times, droplets impacting from higher heights demonstrate increased heat transfer effectiveness due to expanded contact area. The results suggest that reducing droplet spreading time, as opposed to contact time alone, can be a more effective strategy for minimizing heat transfer. The results presented here highlight the importance of both contact area and contact time on the heat exchange between a droplet and a cold superhydrophobic surface.</p>","PeriodicalId":100381,"journal":{"name":"Droplet","volume":"3 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dro2.124","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141968326","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}

{"title":"Liquid surface depression and bubble generation by acoustic radiation","authors":"Zilong Fang,&nbsp;Kai-Tak Wan,&nbsp;Mohammad E. Taslim","doi":"10.1002/dro2.123","DOIUrl":"https://doi.org/10.1002/dro2.123","url":null,"abstract":"<p>Liquid surfaces can be depressed by applying acoustic radiation force. The balance between the acoustic radiation force, surface tension force, and buoyant force sustains the stable dimple depression. Beyond a certain threshold, higher acoustic radiation force leads to instability and bubble formation. The bubble size is determined by the acoustic radiation force and the liquid surface tension. Effective management of bubble generation can be achieved by controlling acoustic radiation waves. A novel method for creating depression on liquid surfaces and generating bubbles is described, which requires neither gas supply nor direct contact with equipment.</p>","PeriodicalId":100381,"journal":{"name":"Droplet","volume":"3 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dro2.123","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141967691","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}

{"title":"Magnetic nanofluid-based liquid marble for a self-powered mechanosensation","authors":"Manhui Chen,&nbsp;Ziwei Liu,&nbsp;Yike Li,&nbsp;Shanfei Zhang,&nbsp;Peng Chen,&nbsp;Pengyu Zhang,&nbsp;Bin Su","doi":"10.1002/dro2.122","DOIUrl":"10.1002/dro2.122","url":null,"abstract":"<p>Magnetic nanofluid possesses the characteristic of interfering with the propagation of the magnetic field, endowing it with the sensing property in motion. However, the residual adhesion of magnetic nanofluid as it flows over solid surfaces remains an open question. Liquid marbles allow for quantities of liquids to be encapsulated by hydrophobic particles, ensuring a unique nonstick property for utilization in different applications. In this study, being capsuled by hydrophobic nano-/microscale powders, a magnetic nanofluid-based liquid marble (MNLM) with well mechanical stability has been fabricated. A magnetic nanofluid posture detector (MNPD), which consists of an MNLM, a magnetic tube, and coils, has been assembled that can convert mechanical energy to electricity as it freely rolls on the solid surface. Gesture recognition can be achieved when combining five MNPDs with fingers. The fabricated MNPD possesses a good signal recognition capability, which can separately distinguish the bending of each finger. Moreover, a variety of language hand gestures with specific meanings (digits, letters, “OK,” and “I Love You”) can be further recognized through corresponding combinations. The potential of MNPD in the realm of gesture recognition will offer a novel avenue for flexible wearables.</p>","PeriodicalId":100381,"journal":{"name":"Droplet","volume":"3 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dro2.122","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140668407","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}

{"title":"Deposition of shear-thinning viscoelastic fluids by an elongated bubble in a circular channel regarding the weakly elastic regime","authors":"SungGyu Chun,&nbsp;Zhengyu Yang,&nbsp;Jie Feng","doi":"10.1002/dro2.121","DOIUrl":"10.1002/dro2.121","url":null,"abstract":"<p>Thin-film deposition of fluids is ubiquitous in a wide range of engineering and biological applications, such as surface coating, polymer processing, and biomedical device fabrication. While the thin viscous film deposition in Newtonian fluids has been extensively investigated, the deposition dynamics in frequently encountered non-Newtonian complex fluids remain elusive, with respect to predictive scaling laws for the film thickness. Here, we investigate the deposition of thin films of shear-thinning viscoelastic fluids by the motion of a long bubble translating in a circular capillary tube. Considering the weakly elastic regime with a shear-thinning viscosity, we provide a quantitative measurement of the film thickness with systematic experiments. We further harness the recently developed hydrodynamic lubrication theory to quantitatively rationalize our experimental observations considering the effective capillary number <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>C</mi>\u0000 <msub>\u0000 <mi>a</mi>\u0000 <mi>e</mi>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$Ca_mathrm{e}$</annotation>\u0000 </semantics></math> and the effective Weissenberg number <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>W</mi>\u0000 <msub>\u0000 <mi>i</mi>\u0000 <mi>e</mi>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$Wi_mathrm{e}$</annotation>\u0000 </semantics></math>, which describe the shear-thinning and the viscoelastic effects on the film formation, respectively. The obtained scaling law agrees reasonably well with the experimentally measured film thickness for all test fluids. Our work may potentially advance the fundamental understanding of the thin-film deposition in a confined geometry and provide valuable engineering guidance for processes that incorporate thin-film flows and non-Newtonian fluids.</p>","PeriodicalId":100381,"journal":{"name":"Droplet","volume":"3 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dro2.121","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140670865","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}

{"title":"Frontispiece 2, Volume 3, Number 2, April 2024","authors":"Shaojun Jiang,&nbsp;Dong Wu,&nbsp;Jiawen Li,&nbsp;Jiaru Chu,&nbsp;Yanlei Hu","doi":"10.1002/dro2.134","DOIUrl":"https://doi.org/10.1002/dro2.134","url":null,"abstract":"<p><b>Frontispiece 2</b>: The cover image is based on the Review Article <i>Magnetically responsive manipulation of droplets and bubbles</i> by Jiang et al.</p><p>Based on the merits of remote control, exceptional biocompatibility, and no need for complex circuits, magnetically responsive manipulation of droplets/bubbles has a wide range of application potential in biomedical, microchemistry, analytical detection, and so on. This review provides a comprehensive and systematic overview of the current state of the art of the magnetically responsive manipulation of droplets and bubbles. (DOI: 10.1002/dro2.117)\u0000\u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure></p>","PeriodicalId":100381,"journal":{"name":"Droplet","volume":"3 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dro2.134","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140556363","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}

{"title":"Front Cover, Volume 3, Number 2, April 2024","authors":"Xiaoliang Ji,&nbsp;Wenxuan Zhong,&nbsp;Kangqi Liu,&nbsp;Yichen Jiang,&nbsp;Hongyue Chen,&nbsp;Wei Zhao,&nbsp;Duyang Zang","doi":"10.1002/dro2.126","DOIUrl":"https://doi.org/10.1002/dro2.126","url":null,"abstract":"<p><b>Front Cover</b>: The cover image is based on the Research Article <i>Extraordinary stability of surfactant-free bubbles suspended in ultrasound</i> by Ji et al.</p><p>By using ultrasonic levitation, the suspending bubble exhibits extraordinary stability against liquid drainage, thus achieving significantly prolonged bubble life which resembles that aboard the space station. (DOI: 10.1002/dro2.119)\u0000\u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure></p>","PeriodicalId":100381,"journal":{"name":"Droplet","volume":"3 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dro2.126","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140556372","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}

{"title":"Back Cover, Volume 3, Number 2, April 2024","authors":"Yuyang Wang,&nbsp;Zecong Fang,&nbsp;Sen Li,&nbsp;Kexin Lin,&nbsp;Zhifeng Zhang,&nbsp;Junyi Chen,&nbsp;Tingrui Pan","doi":"10.1002/dro2.127","DOIUrl":"https://doi.org/10.1002/dro2.127","url":null,"abstract":"<p><b>Back Cover</b>: The cover image is based on the Research Article <i>Droplet Laplace valve-enabled glaucoma implant for intraocular pressure management</i> by Wang et al.</p><p>This cover image depicts an innovative moving-parts-free microvalve with customizable and consistent threshold valving pressures for the treatment of refractory glaucoma. Operating on the principle of capillarity-driven flow discretization, it showcases a simple design with a droplet-generation nozzle and collecting reservoir. Such technology holds great promise for glaucoma implants and other microsystems that require a passive yet highly reliable microvalve. (DOI: 10.1002/dro2.109)\u0000\u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure></p>","PeriodicalId":100381,"journal":{"name":"Droplet","volume":"3 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dro2.127","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140556359","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}