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Akuoko SY, Kwon KS. Fabrication and Applications of Nature-Inspired Surfaces with Selective Wettability. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024. [PMID: 39046090 DOI: 10.1021/acs.langmuir.4c00919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/25/2024]
Abstract
Inspired by the Stenocora beetle, selective wettability surfaces incorporate alternating wettable and nonwettable surface features that have received substantial attention over the past two decades. These surfaces are sought after for their very promising potential to drive progress in numerous application fields, including ecological protection, biomedical sciences, and industrial technologies. However, despite ongoing efforts to produce such surfaces in commercial quantities, understanding their basic fabrication concepts for practical applications can be challenging, especially for novices, given the vast technical literature in this area. This review, therefore, aims to elucidate the principles of wettability, along with the evolution of selective wettability surfaces and their uses. Beginning with a summary of the essential history and theory of wetting, we explore naturally occurring surfaces that have influenced wetting studies. We then detail state-of-the-art methods for fabricating these unique biwetting surfaces and show how contemporary science employs such designs in solving real-world problems. Finally, we offer an outlook for future research prospects on scalable, printing-based fabrication methods.
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Affiliation(s)
- Stephen Yaw Akuoko
- Department of Electronic Materials, Devices and Equipment Engineering, Soonchunhyang University, 22 Soonchunhyang-ro, Asan, Chungnam 31538, South Korea
| | - Kye-Si Kwon
- Department of Electronic Materials, Devices and Equipment Engineering, Soonchunhyang University, 22 Soonchunhyang-ro, Asan, Chungnam 31538, South Korea
- Department of Mechanical Engineering, Soonchunhyang University, 22 Soonchunhyang-ro, Asan, Chungnam 31538, South Korea
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Josyula T, Kumar Malla L, Thomas TM, Kalichetty SS, Sinha Mahapatra P, Pattamatta A. Fundamentals and Applications of Surface Wetting. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:8293-8326. [PMID: 38587490 DOI: 10.1021/acs.langmuir.3c03339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
In an era defined by an insatiable thirst for sustainable energy solutions, responsible water management, and cutting-edge lab-on-a-chip diagnostics, surface wettability plays a pivotal role in these fields. The seamless integration of fundamental research and the following demonstration of applications on these groundbreaking technologies hinges on manipulating fluid through surface wettability, significantly optimizing performance, enhancing efficiency, and advancing overall sustainability. This Review explores the behavior of liquids when they engage with engineered surfaces, delving into the far-reaching implications of these interactions in various applications. Specifically, we explore surface wetting, dissecting it into three distinctive facets. First, we delve into the fundamental principles that underpin surface wetting. Next, we navigate the intricate liquid-surface interactions, unraveling the complex interplay of various fluid dynamics, as well as heat- and mass-transport mechanisms. Finally, we report on the practical realm, where we scrutinize the myriad applications of these principles in everyday processes and real-world scenarios.
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Affiliation(s)
- Tejaswi Josyula
- Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, India
| | - Laxman Kumar Malla
- School of Mechanical Sciences, Odisha University of Technology and Research, Bhubaneswar 751029, India
| | - Tibin M Thomas
- Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, India
| | | | - Pallab Sinha Mahapatra
- Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, India
| | - Arvind Pattamatta
- Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, India
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Banerjee U, Shyam S, Mitra SK. Magnetic Control of Water Droplet Impact onto Ferrofluid Lubricated Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:4049-4059. [PMID: 36893478 DOI: 10.1021/acs.langmuir.2c03404] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Controlling the impact process of a droplet impacting a liquid film has remained a wide-open challenge. The existing passive techniques lack precise on-demand control of the impact dynamics of droplets. The present study introduces a magnet-assisted approach to control water droplets' impact dynamics. We show that by incorporating a thin, magnetically active ferrofluid film, the overall droplet impact phenomena of the water droplets could be controlled. It is found that by modifying the distribution of the magnetic nanoparticles (MNPs) present inside the ferrofluid using a permanent magnet, the spreading and retraction behavior of the droplet could be significantly controlled. In addition to that, we also show that by altering the impact Weber number (Wei), and the magnetic Bond number (Bom), the outcomes of droplet impact could be precisely controlled. We reveal the role of the various forces on the consequential effects of droplet impact with the help of phase maps. Without the magnetic field, we discovered that the droplet impact on ferrofluid film results in no-splitting, jetting, and splashing regimes. On the other hand, the presence of magnetic field results in the no-splitting and jetting regime. However, beyond a critical magnetic field, the ferrofluid film gets transformed into an assembly of spikes. In such scenarios, the droplet impact only results in no-splitting and splashing regimes, while the jetting regime remains absent. The outcome of our study may find potential applications in chemical engineering, material synthesis, and three-dimensional (3D) printing where the control and optimization of the droplet impact process are desirable.
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Affiliation(s)
- Utsab Banerjee
- Micro & Nano-scale Transport Laboratory, Waterloo Institute for Nanotechnology, Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - Sudip Shyam
- Micro & Nano-scale Transport Laboratory, Waterloo Institute for Nanotechnology, Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - Sushanta K Mitra
- Micro & Nano-scale Transport Laboratory, Waterloo Institute for Nanotechnology, Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
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Satpathi NS, Nampoothiri KN, Sen AK. Effects of surface acoustic waves on droplet impact dynamics. J Colloid Interface Sci 2023; 641:499-509. [PMID: 36948105 DOI: 10.1016/j.jcis.2023.03.058] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 03/02/2023] [Accepted: 03/08/2023] [Indexed: 03/13/2023]
Abstract
HYPOTHESIS Surface acoustic waves (SAW) propagating along a solid surface can significantly affect the dynamics of droplet impact. Although droplet impact in presence of SAW has been attempted recently, here, we investigate the effects of surface wettability, droplet size, impact velocity, and SAW power on the impact and spreading dynamics along with post-impact oscillation dynamics of a drop. EXPERIMENTS Here, we study droplet impact on a surface exposed to traveling SAW produced using an interdigitated electrode patterned on a piezoelectric substrate. The effects of Weber number (We), surface wettability, and SAW power on the impact and spreading dynamics and post-impact oscillation dynamics are studied. FINDINGS Our study unravels that the interplay between capillary and viscous forces, and inertia forces arising due to pre-impact kinetic energy and SAW-induced bulk acoustic streaming underpins the phenomena. Remarkably, we find that the effect of SAW on droplet impact dynamics is predominant in the case of a hydrophilic (HPL) substrate at a higher SAW power and smaller We and hydrophobic (HPB) substrate irrespective of SAW power. Our study reveals that the maximum droplet spreading diameter increases with SAW power at smaller We for an HPL surface whereas it is independent of SAW power at higher We. Post-impact oscillation of a droplet over an HPL surface is found to be overdamped with a smaller amplitude compared to an HPB substrate, and a faster decay in oscillation amplitude is observed in the case of an HPB surface and higher We. Our study provides an improved understanding of droplet impact on a surface exposed to SAW that may find relevance in various practical applications.
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Affiliation(s)
- N S Satpathi
- Micro Nano Bio Fluidics Unit, Fluid Systems Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai - 600036, Tamil Nadu, India
| | - K N Nampoothiri
- Micro Nano Bio Fluidics Unit, Fluid Systems Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai - 600036, Tamil Nadu, India
| | - A K Sen
- Micro Nano Bio Fluidics Unit, Fluid Systems Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai - 600036, Tamil Nadu, India.
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Lathia R, Nampoothiri KN, Sagar N, Bansal S, Modak CD, Sen P. Advances in Microscale Droplet Generation and Manipulation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:2461-2482. [PMID: 36779356 DOI: 10.1021/acs.langmuir.2c02905] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Microscale droplet generation and manipulation have widespread applications in numerous fields, from biochemical assays to printing and additive manufacturing. There are several techniques for droplet handling. Most techniques, however, can generate and work with only a limited range of droplet sizes. Furthermore, there are constraints regarding the workable variety of fluid properties (e.g., viscosity, surface tension, mass loading, etc.). Recent works have focused on developing techniques to overcome these limitations. This feature article discusses advances in this area that cover a wide range of droplet sizes from subpicoliter to microliter.
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Affiliation(s)
- Rutvik Lathia
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Krishnadas Narayanan Nampoothiri
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, India
- Department of Mechanical Engineering, Amrita School of Engineering, Amrita Vishwa Vidyapeetham, Chennai 601103, India
| | - Nitish Sagar
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Shubhi Bansal
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, India
- University College London, London WC1E 6BT, U.K
| | - Chandantaru Dey Modak
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, India
- Laboratoire de Biophysique et Evolution, UMR CNRS-ESPCI 8231 Chimie Biologie Innovation, PSL University, ESPCI Paris, 10 rue Vauquelin, 75005 Paris, France
| | - Prosenjit Sen
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, India
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Jaiswal AK, Khandekar S. Role of offset during drop-on-drop impact dynamics on a superhydrophobic substrate. RESULTS IN SURFACES AND INTERFACES 2023. [DOI: 10.1016/j.rsurfi.2023.100102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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Nampoothiri KN, Satpathi NS, Sen AK. Surface acoustic wave-based generation and transfer of droplets onto wettable substrates. RSC Adv 2022; 12:23400-23410. [PMID: 36090390 PMCID: PMC9382648 DOI: 10.1039/d2ra04089a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Accepted: 08/09/2022] [Indexed: 11/21/2022] Open
Abstract
Fluid manipulation using surface acoustic waves (SAW) has been utilized as a promising technique in the field of microfluidics due to its numerous advantages, over other active techniques, such as low power requirement, facile fabrication methods, and non-invasive nature. Even though SAW-based generation of micron-sized droplets through atomization has been studied, the role of substrate wettability on the characteristics of the transferred droplets has not been explored to date. Here, we study the generation and effective transfer of micron-sized droplets using SAW onto wettable substrates whose water contact angles vary from 5° to 145°. The characteristics of transferred droplets after impacting the wettable substrates are characterized in terms of the contact line diameter and polydispersity index. A theoretical model is formulated to predict the initial average size of the transferred droplets on the wettable substrates of different contact angles. The variation of polydispersity and number density with contact angle is explained by considering droplet coalescence and bouncing. The relevance of the technique in biological assays is demonstrated by transferring droplets of streptavidin protein samples onto a substrate. Investigation of surface acoustic wave-based generation and transfer of droplets onto wettable substrates is carried out and explained in terms of polydispersity index. Transfer of biomolecules is demonstrated to highlight the technique.![]()
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Affiliation(s)
| | - Niladri Sekhar Satpathi
- Fluid Systems Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai-600036, India
| | - Ashis Kumar Sen
- Fluid Systems Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai-600036, India
- Micro Nano Bio Fluidics Group, Indian Institute of Technology Madras, Chennai-600036, India
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