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Tran H, He Z, Pirdavari P, Pack MY. Interplay of Drop Shedding Mechanisms on High Wettability Contrast Biphilic Stripe-Patterned Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:17551-17559. [PMID: 37987777 DOI: 10.1021/acs.langmuir.3c03042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
To improve the rate of DWC, numerous studies have adjusted the distribution of drops through biphilic surface patterning and wettability gradients to control the nucleation and drop shedding rates on the condensing surface, yet the connection between drop shedding mechanisms and surface wettability patterning remains unclear. Moreover, wettability patterning places geometric bounds on the governing forces (i.e., gravity, capillary, and inertia), which drive the droplet shedding mechanisms. Thus, the subsequent influence of droplet distribution along the DWC regions on the shedding mechanisms may not be known a priori. In this study, the area fraction, ADWC, of the DWC and also the DWC region width, LN, were varied between 10 and 50% and 0.5-1.5 mm, respectively, to probe the dominant droplet shedding mechanisms on a high wettability contrast surface (i.e., the contact angle on the DWC was 159 ± 3.4° and the hysteresis 9 ± 3.6°, whereas the FWC was nearly perfectly wetting). Humid air was introduced inside a custom-built chamber with the upright steady-state condensation imaged by both real-time and high-speed imaging techniques. We found that the droplet shedding mechanisms changed with increasing LN where the sliding drop radii are reduced with LN while the jumping drop radii remained unchanged with LN. The maximum drop size for shedding also decreased by 13%, which we attribute to the secondary droplet inertia, which helps gravity overcome the capillary retention force. Lastly, although many studies have probed DWC enhancements via surface wettability patterning, an optimal combination of ADWC and LN provided in this study significantly aids in the improvement of future DWC-based condensers and water collector applications.
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Affiliation(s)
- Huy Tran
- Department of Mechanical Engineering, Baylor University, One Bear Place #97356, Waco, Texas 76798, United States
| | - Ziwen He
- Department of Mechanical Engineering, Baylor University, One Bear Place #97356, Waco, Texas 76798, United States
| | - Pooria Pirdavari
- Department of Mechanical Engineering, Baylor University, One Bear Place #97356, Waco, Texas 76798, United States
| | - Min Y Pack
- Department of Mechanical Engineering, Baylor University, One Bear Place #97356, Waco, Texas 76798, United States
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2
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Toppi A, Busk LL, Hu H, Dogan AA, Jönsson A, Taboryski RJ, Dufva M. Photolithographic Patterning of FluorAcryl for Biphilic Microwell-Based Digital Bioassays and Selection of Bacteria. ACS APPLIED MATERIALS & INTERFACES 2021; 13:43914-43924. [PMID: 34491739 DOI: 10.1021/acsami.1c10096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
FluorAcryl 3298 (FA) is a UV-curable fluoroacrylate polymer commonly employed as a chemically resistant, hydrophobic, and oleophobic coating. Here, FA was used in a cleanroom-based microstructuring process to fabricate hydrophilic-in-hydrophobic (HiH) micropatterned surfaces containing femtoliter-sized well arrays. A short protocol involving direct UV photopatterning, an etching step, and final recovery of the hydrophobic properties of the polymer produced patterned substrates with micrometer resolution. Specifically, HiH microwell arrays were obtained with a well diameter of 10 μm and various well depths ranging from 300 nm to 1 μm with high reproducibility. The 300 nm deep microdroplet array (MDA) substrates were used for digital immunoassays, which presented a limit of detection in the attomolar range. This demonstrated the chemical functionality of the hydrophilic and hydrophobic surfaces. Furthermore, the 1 μm deep wells could efficiently capture particles such as bacteria, whereas the 300 nm deep substrates or other types of flat HiH molecular monolayers could not. Capturing a mixture of bacteria expressing red- and green-fluorescent proteins, respectively, served as a model for screening and selection of specific phenotypes using FA-MDAs. Here, green-fluorescent bacteria were specifically selected by overlaying a solution of gelatin methacryloyl (GelMA) mixed with a photoinitiator and using a high-magnification objective, together with custom pinholes, in a common fluorescence microscope to cross-link the hydrogel around the bacteria of interest. In conclusion, due to the straightforward processing, versatility, and low-price, FA is an advantageous alternative to more commonly used fluorinated materials, such as CYTOP or Teflon-AF, for the fabrication of HiH microwell arrays and other biphilic microstructures.
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Affiliation(s)
- Arianna Toppi
- Department of Health Technology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Louise L Busk
- Department of Health Technology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Hongxia Hu
- Department of Health Technology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Asli A Dogan
- Department of Health Technology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Alexander Jönsson
- Department of Health Technology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Rafael J Taboryski
- DTU Nanolab, National Centre for Nano Fabrication and Characterization, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Martin Dufva
- Department of Health Technology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
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3
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Mandsberg NK, Højgaard J, Joshi SS, Nielsen LH, Boisen A, Hwu ET. Consumer-Grade Inkjet Printer for Versatile and Precise Chemical Deposition. ACS OMEGA 2021; 6:7786-7794. [PMID: 33778290 PMCID: PMC7992151 DOI: 10.1021/acsomega.1c00282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Accepted: 02/19/2021] [Indexed: 06/12/2023]
Abstract
Two simple, mechanical modifications are introduced to a consumer-grade inkjet printer to greatly increase its applicability. First, roller isolation bars are added to unlock multiple prints on the same substrate without smearing. This enables printing on a diverse set of substrates (rigid, elastic, liquid, granular, and sticky). Second, spring loadings are added to increase the print precision up to 50-fold, which facilitates alignment to a pre-patterned substrate or between successive prints. Utilizing the expanded substrate compatibility and the increased print precision, we explore tunable loading of drug combinations into microdevices. This loading method has promising applications within point-of-care personalized medication. Furthermore, we show how inkjet printers with array-type printheads (in our case, 6 x 90 nozzles) allow for quasi-simultaneous loading of reactants into microfluidic systems. The ability to do a quasi-simultaneous introduction of chemicals may be particularly useful for studies of rapidly reacting systems of three or more reactants, where premature introduction can shift the initial conditions from the intended. We believe that our modifications to an affordable system will inspire researchers to explore the possibilities of inkjet printing even further.
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Affiliation(s)
- Nikolaj Kofoed Mandsberg
- Center for Intelligent Drug
Delivery and Sensing Using Microcontainers and Nanomechanics (IDUN),
Department of Health Technology, Technical
University of Denmark, 2800 Kgs Lyngby, Denmark
| | - Jesper Højgaard
- Center for Intelligent Drug
Delivery and Sensing Using Microcontainers and Nanomechanics (IDUN),
Department of Health Technology, Technical
University of Denmark, 2800 Kgs Lyngby, Denmark
| | - Shreya Suhas Joshi
- Center for Intelligent Drug
Delivery and Sensing Using Microcontainers and Nanomechanics (IDUN),
Department of Health Technology, Technical
University of Denmark, 2800 Kgs Lyngby, Denmark
| | - Line Hagner Nielsen
- Center for Intelligent Drug
Delivery and Sensing Using Microcontainers and Nanomechanics (IDUN),
Department of Health Technology, Technical
University of Denmark, 2800 Kgs Lyngby, Denmark
| | - Anja Boisen
- Center for Intelligent Drug
Delivery and Sensing Using Microcontainers and Nanomechanics (IDUN),
Department of Health Technology, Technical
University of Denmark, 2800 Kgs Lyngby, Denmark
| | - En Te Hwu
- Center for Intelligent Drug
Delivery and Sensing Using Microcontainers and Nanomechanics (IDUN),
Department of Health Technology, Technical
University of Denmark, 2800 Kgs Lyngby, Denmark
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Shen Y, Zou H, Wang S. Condensation Frosting on Micropillar Surfaces - Effect of Microscale Roughness on Ice Propagation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:13563-13574. [PMID: 33146014 DOI: 10.1021/acs.langmuir.0c02353] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Microscale surface structures have been widely explored as a promising tool for antifreezing or frost avoidance on heat transfer surfaces. Despite studies of many surface feature designs, the mechanisms associated with condensation freezing and ice propagation on microstructured surfaces have yet to be thoroughly elucidated, espectially when it comes to quantitative understanding. In this work, condensation freezing on circular micropillar surfaces is investigated, with varying pillar spacing and height (layout/microscale roughness) but a constant pillar diameter. The pillar layout is found to have significant effects on both liquid nucleation and neighboring droplet interactions, as reflected by the condensation droplet distribution prior to soilidification and eventually the freezing front propagation area velocity. In general, nucleation is preferred on the pillar top rather than the bottom of the pillared surface unless there is a large distance between the pillars. Interactions between neighboring droplets solely on pillar tops (or bottom surfaces) can induce heterogeneity in the droplet distribution and slow freezing front propagation. Based on the roles the pillars play in nucleation, droplet coalescence, and ice bridging, four different condensation states are identified and related to the layout of the pillars, and the freezing front area propagation velocity is found to be different in each state. The findings provide a quantitative basis for designing antifreezing surfaces, applicable to a wide range of thermal systems.
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Affiliation(s)
- Yuchen Shen
- Department of Mechanical Science and Engineering, University of Illinois at Urbana- Champaign, Urbana, Illinois 61801-3028, United States
| | - Haoyang Zou
- Department of Mechanical Science and Engineering, University of Illinois at Urbana- Champaign, Urbana, Illinois 61801-3028, United States
| | - Sophie Wang
- Department of Mechanical Science and Engineering, University of Illinois at Urbana- Champaign, Urbana, Illinois 61801-3028, United States
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Tang G, Niu D, Guo L, Xu J. Failure and Recovery of Droplet Nucleation and Growth on Damaged Nanostructures: A Molecular Dynamics Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:13716-13724. [PMID: 33147034 DOI: 10.1021/acs.langmuir.0c02809] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The condensate flooding during dropwise condensation causes serious deterioration in heat transfer performance. In this study, the three-dimensional large-scale molecular dynamics simulation is carried out to investigate the droplet state transition from local flooding mode to Wenzel or from Wenzel to Cassie due to the droplet coalescence under the effect of nanostructure size. In particular, the effect of nanostructure breakage on droplet nucleation and growth is discussed to reveal the mechanism of dropwise condensation heat transfer deterioration. As a potential solution, the lubricant-impregnated surface is proposed to recover the preferred Cassie state by regulating the dynamic wetting characteristics of droplets, and thus the detrimental effect of nanostructure breakage could be effectively avoided.
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Affiliation(s)
- Guihua Tang
- MOE Key Laboratory of Thermo-Fluid Science and Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Dong Niu
- MOE Key Laboratory of Thermo-Fluid Science and Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Lin Guo
- MOE Key Laboratory of Thermo-Fluid Science and Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Jinliang Xu
- Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization, North China Electric Power University, Beijing 102206, China
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Xing D, Wang R, Wu F, Gao X. Confined Growth and Controlled Coalescence/Self-Removal of Condensate Microdrops on a Spatially Heterogeneously Patterned Superhydrophilic-Superhydrophobic Surface. ACS APPLIED MATERIALS & INTERFACES 2020; 12:29946-29952. [PMID: 32510195 DOI: 10.1021/acsami.0c04922] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Manipulating condensate nucleation, growth, coalescence, and self-removal via bionic super-wettability surfaces has attracted intensive interest because of their significance in fundamental research and technological innovations, for example, water harvesting, power generation, air conditioning, and thermal management. However, it is still a challenge to simultaneously realize confined growth, coalescence, and self-ejection of condensate microdrops, which has not been reported to date. Here, we propose and demonstrate a type of new and more efficient coalescence/self-removal method based on spatially confined growth/coalescence/self-ejection of condensate microdrops, which can be realized using a rationally designed superhydrophobic surface with spatially heterogeneously patterned superhydrophilic microdots (SMDs). Exemplified by superhydrophobic closely packed zinc oxide nanoneedles with SMD patterns, we investigate how the geometric parameters of SMD patterns be designed to simultaneously realize the spatially confined growth/coalescence/self-ejection of patterned microdrops, which are rationalized via theoretical analyses.
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Affiliation(s)
- Dandan Xing
- Functional Materials and Interfaces Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, P. R. China
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei 230026, P. R. China
| | - Rui Wang
- Functional Materials and Interfaces Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, P. R. China
| | - Feifei Wu
- Functional Materials and Interfaces Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, P. R. China
| | - Xuefeng Gao
- Functional Materials and Interfaces Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, P. R. China
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei 230026, P. R. China
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Telecka A, Mandsberg NK, Li T, Ludvigsen E, Ndoni S, Di Mundo R, Palumbo F, Fiutowski J, Chiriaev S, Taboryski R. Mapping the transition to superwetting state for nanotextured surfaces templated from block-copolymer self-assembly. NANOSCALE 2018; 10:20652-20663. [PMID: 30394480 DOI: 10.1039/c8nr07941b] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Adding roughness to hydrophilic surfaces is generally expected to enhance their wetting by water. Indeed, global free energy minimization predicts decreasing contact angles when roughness factor or surface energy increases. However, experimentally it is often found that water spreading on rough surfaces is impeded by pinning effects originating from local free energy minima; an effect, largely neglected in scientific literature. Here, we utilize Laplace pressure as a proxy for these local minima, and we map the transition to a superwetting state of hydrophilic nano-textured surfaces in terms of surface chemistry and texture geometry. We demonstrate the effect for polymer model surfaces templated from block-copolymer self-assembly comprising dense, nano-pillar arrays exhibiting strong pinning in their pristine state. By timed argon plasma exposure, we tune surface chemistry to map the transition into the superwetting state of low contact angle, which we show coincide with the surface supporting hemiwicking flow. For the near-ideal model surfaces, the transition to the superwetting state occurs below a critical material contact angle of ∼50°. We show that superwetting surfaces possess anti-fogging properties, and demonstrate long term stability of the superwetting effect by coating the nanotextured surfaces with ∼10 nm thin films of either tungsten or silica.
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Affiliation(s)
- Agnieszka Telecka
- Department of Micro- and Nanotechnology, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
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Telecka A, Li T, Ndoni S, Taboryski R. Nanotextured Si surfaces derived from block-copolymer self-assembly with superhydrophobic, superhydrophilic, or superamphiphobic properties. RSC Adv 2018. [DOI: 10.1039/c8ra00414e] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We demonstrate the use of wafer-scale nanolithography based on block-copolymer (BCP) self-assembly for the fabrication of surfaces with enhanced wetting properties.
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Affiliation(s)
- Agnieszka Telecka
- Department of Micro- and Nanotechnology
- Technical University of Denmark
- Denmark
| | - Tao Li
- Department of Micro- and Nanotechnology
- Technical University of Denmark
- Denmark
- Department of Electronic and Electrical Engineering
- University College London
| | - Sokol Ndoni
- Department of Micro- and Nanotechnology
- Technical University of Denmark
- Denmark
- Center for Nanostructured Graphene, CNG
- Technical University of Denmark
| | - Rafael Taboryski
- Department of Micro- and Nanotechnology
- Technical University of Denmark
- Denmark
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