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Wang X, Yuan Z, Chen F, Yao X, Yu F, Wang S. Forced Wetting of Shear-Thinning Fluids in Confined Capillaries. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024. [PMID: 39320980 DOI: 10.1021/acs.langmuir.4c02728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/27/2024]
Abstract
Dynamic wetting in confined spaces is pivotal for the functional efficiency of biological organisms and offers significant potential for optimizing microdevices. The fluids encountered in such scenarios often exhibit shear-thinning behavior, which gives rise to complex interfacial phenomena. Here, we present an intriguing wetting phenomenon for shear-thinning fluids in confined capillary spaces. The employed shear-thinning fluids, carboxymethyl cellulose aqueous solutions with mass fractions of 0.5, 1.0, and 1.5 wt %, exhibit an intermediate state between ideal viscoelastic liquids, viscoelastic solids, and gel-like properties. We elucidate the geometric effect on its capillary wetting behavior, demonstrating that distortion of the moving contact line alters flow dynamics near the front corner, modifying the viscous resistance. This intricate interplay between the modified viscous resistance and the driving force results in a novel dynamic equilibrium distinct from that in Newtonian fluids. We further reveal that the viscous resistance in confined capillaries is controlled by both the morphology of the moving contact line and the shear-thinning exponent, particularly within the range of 0.7 to 1. This novel mechanism provides a pathway for manipulating the wetting dynamics of complex fluids in confined spaces.
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Affiliation(s)
- Xiong Wang
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong 999077, China
| | - Zhenyue Yuan
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong 999077, China
| | - Feipeng Chen
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Kowloon, Hong Kong 999077, China
| | - Xiaoxue Yao
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong 999077, China
| | - Fanfei Yu
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong 999077, China
| | - Steven Wang
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong 999077, China
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2
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Azimi Yancheshme A, Palmese GR, Alvarez NJ. A generalized scaling theory for spontaneous spreading of Newtonian fluids on solid substrates. J Colloid Interface Sci 2023; 636:677-688. [PMID: 36680958 DOI: 10.1016/j.jcis.2023.01.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 01/03/2023] [Accepted: 01/05/2023] [Indexed: 01/09/2023]
Abstract
HYPOTHESIS There exists a generalized solution for the spontaneous spreading dynamics of droplets taking into account the influence of interfacial tension and gravity. EXPERIMENTS This work presents a generalized scaling theory for the problem of spontaneous dynamic spreading of Newtonian fluids on a flat substrate using experimental analysis and numerical simulations. More specifically, we first validate and modify a dynamic contact angle model to accurately describe the dependency of contact angle on the contact line velocity, which is generalized by the capillary number. The dynamic contact model is implemented into a two-phase moving mesh computational fluid dynamics (CFD) model, which is validated using experimental results. FINDINGS We show that the spreading process is governed by three important parameters: the Bo number, viscous timescale τviscous, and static advancing contact angle, θs. More specifically, there exists a master spreading curve for a specific Bo and θs by scaling the spreading time with the τviscous. Moreover, we developed a correlation for prediction of the equilibrium shape of the droplets as a function of both Bo and θs. The results of this study can be used in a wide range of applications to predict both dynamic and equilibrium shape of droplets, such as in droplet-based additive manufacturing.
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Affiliation(s)
| | - Giuseppe R Palmese
- Chemical and Biological Engineering, Drexel University, Philadelphia, PA 19104, USA
| | - Nicolas J Alvarez
- Chemical and Biological Engineering, Drexel University, Philadelphia, PA 19104, USA
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3
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Zhang LZ, Xu SY, Wang YF, Yang YR, Zheng SF, Gao SR, Wang XD, Lee DJ. Impact Dynamics of a Single Droplet on Hydrophobic Cylinders: A Lattice Boltzmann Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:11860-11872. [PMID: 36130147 DOI: 10.1021/acs.langmuir.2c01271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
This study numerically investigates the effects of the Weber number (We) and cylinder-to-droplet radius ratio (R*) on the impact dynamics of a low-viscosity droplet on a hydrophobic cylinder by the lattice Boltzmann method. The intrinsic contact angle of the surface is chosen as θ0 = 122°± 2°, which ensures a representative hydrophobicity. The regime diagram of the impact dynamics in the parameter space of We versus R* is established with categories of split and nonsplit regimes. The droplet would split during impact as α = We/R* exceeds a critical value. In the nonsplit regime, the droplet bounces off the cylinder at most Weber numbers unless the impact velocity is minuscule (We < 2). The contact time of the droplet on the cylinder surface decreases with increasing R* or decreasing We, indicating bouncing is facilitated under such conditions. This can be explained by the suppressed adhesion dissipation between the droplet and surface due to a reduction in the contact area. In the split regime, sufficient kinetic energy inside the impacting droplet determines whether the whole droplet could detach from the surface. With a small cylinder (R* < 0.83) and large We (>25), the adhesion effect is weakened for the side fragments because of the small contact area, and it facilitates the dripping of fragments. For other conditions, the detachment, especially for the tiny droplet on the cylinder top, only occurs if the deformation is prominent at We > 35. Moreover, the spreading dynamics of the impacting droplet are also highlighted in this work.
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Affiliation(s)
- Ling-Zhe Zhang
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
| | - Sheng-Yao Xu
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
| | - Yi-Feng Wang
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
| | - Yan-Ru Yang
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
| | - Shao-Fei Zheng
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
| | - Shu-Rong Gao
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
| | - Xiao-Dong Wang
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
| | - Duu-Jong Lee
- Department of Mechanical Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon 999077, Hong Kong
- Department of Chemical Engineering & Materials Science, Yuan-Ze University, Chungli 320, Taiwan
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Wang J, Cao Y, Li G. Comparative Study on the Spreading Behavior of Oil Droplets over Teflon Substrates in Different Media Environments. Polymers (Basel) 2022; 14:polym14142828. [PMID: 35890608 PMCID: PMC9316502 DOI: 10.3390/polym14142828] [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: 05/27/2022] [Revised: 06/17/2022] [Accepted: 06/20/2022] [Indexed: 11/16/2022] Open
Abstract
This paper comparatively investigated the spreading process of an oil droplet on the surface of highly hydrophobic solid (Teflon) in air and water media using a high-speed imaging technology, and analyzed their differences in spreading behavior from the perspective of empirical relations and energy conservation. Furthermore, the classical HD and MKT wetting models were applied to describe the oil droplet spreading dynamics to reveal the spreading mechanism of oil droplets on the Teflon in different media environments. Results showed that the entire spreading process of oil droplets on Teflon in air could be separated into three stages: the early linear fast spreading stage following θ(t)=θ0+kt , the intermediate exponential slow spreading stage obeying θ(t)=bt−3α, and the late spreading stage described by θ(t)=θeq+a×exp(−t/T). However, the dynamics behavior of dynamic contact angle during the oil droplet spreading on Teflon in water could be well described by these expressions, θ(t)=θ0+kt and θ(t)=θeq+a×exp(−t/T). Clearly, a significant difference in the oil droplet spreading behavior in air and water media was found, and the absence of the intermediate exponential spreading stage in the oil–water–Teflon system could be attributed to the difference in the dissipated energy of the system because the dissipation energy in the oil–water–solid system included not only the viscous dissipation energy of the boundary layer of oil droplet, but also that of the surrounding water which was not included in the dissipation energy of the oil–air–solid system. Moreover, the quantitative analysis of wetting models suggested that the MKT model could reasonably describe the late spreading dynamics of oil droplets (low TPCL velocities), while the HD model may be more suitable for describing the oil droplet spreading dynamics at the early and intermediate spreading stages (high TPCL velocities).
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Affiliation(s)
- Junchao Wang
- Chinese National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, Xuzhou 221116, China;
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, China
| | - Yijun Cao
- Chinese National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, Xuzhou 221116, China;
- School of Chemical Engineering and Technology, Zhengzhou University, Zhengzhou 450001, China;
- Correspondence:
| | - Guosheng Li
- School of Chemical Engineering and Technology, Zhengzhou University, Zhengzhou 450001, China;
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5
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Bazazi P, Hejazi SH. Wetting Dynamics of Nanoparticle Dispersions: From Fully Spreading to Non-sticking and the Deposition of Nanoparticle-Laden Surface Droplets. ACS APPLIED MATERIALS & INTERFACES 2022; 14:20280-20290. [PMID: 35446544 DOI: 10.1021/acsami.2c03156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Controlled transport of liquid droplets on solid surfaces is critical in many practical applications, such as self-cleaning surfaces, coating, drug delivery, and agriculture. Non-adhesive liquid drops levitate on solid surfaces; therefore, they are highly mobile and directed toward desired locations by external stimuli. Although research on liquid-repellent surfaces has proliferated, the existing methods are still limited to creating surface roughness or coating the liquid droplets. Here, we create non-contact aqueous drops on hydrophilic surfaces in an oleic environment and use them to deposit submicrometer droplets encapsulating nanoparticles on solid surfaces. A glass surface is buried under an oil phase that contains a high concentration of Span 80 surfactants, and a drop of silica nanoparticle dispersion is released on the solid surface. We study the effect of surfactant concentration in oil and nanoparticle concentration in water on wetting dynamics and report a plethora of droplet spreading regimes from fully wetting to non-wetting. We find a threshold Span 80 concentration above which surfactant assemblies are formed on the solid and prevent the direct contact of the drop with the surface. At the same time, water-in-oil emulsions are generated at the drop-oil interface. The drop moves and leaves a trace of emulsions with encapsulated nanoparticles on the solid. We demonstrate the possibility of local surface coating with hydrophilic nanoparticles in a hydrophobic medium. The developed methodology in this study is a generic approach facilitating the droplet patterning in numerous applications, from pharmaceutical polymetric carriers to the formulation of cosmetics, insecticides, and biomedical diagnoses.
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Affiliation(s)
- Parisa Bazazi
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary AB T2N 1N4, Canada
| | - Seyed Hossein Hejazi
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary AB T2N 1N4, Canada
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6
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Gao SR, Jin JX, Wei BJ, Zhang LZ, Yang YR, Wang XD, Lee DJ. Rebound Behaviors of Multiple Droplets Simultaneously Impacting a Superhydrophobic Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:11233-11241. [PMID: 34528810 DOI: 10.1021/acs.langmuir.1c01490] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The rebound behaviors of multiple droplets simultaneously impacting a superhydrophobic surface were investigated via lattice Boltzmann method (LBM) simulations. Three rebound regions were identified, i.e., an edge-dominating region, a center-dominating region, and an independent rebound region. The occurrence of the rebound regions strongly depends on the droplet spacing and the associated Weber and Reynolds numbers. Three new rebound morphologies, i.e., a pin-shaped morphology, a downward comb-shaped morphology, and an upward comb-shaped morphology, were presented. Intriguingly, in the edge-dominating region, the central droplets experience a secondary wetting process to significantly prolong the contact time. However, in the center-dominating region, the contact time is dramatically shortened because of the strong interactions generated by the central droplets and the central ridges. These findings provide useful information for practical applications such as self-cleaning, anticorrosion, anti-icing, and so forth.
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Affiliation(s)
- Shu-Rong Gao
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
| | - Jia-Xin Jin
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
| | - Bo-Jian Wei
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
| | - Ling-Zhe Zhang
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
| | - Yan-Ru Yang
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
| | - Xiao-Dong Wang
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
| | - Duu-Jong Lee
- Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon Tong 999077, Hong Kong, China
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7
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Shyam S, Gaikwad HS, Ghalib Ahmed SA, Chakraborty B, Mondal PK. Investigations into the Complete Spreading Dynamics of a Viscoelastic Drop on a Spherical Substrate. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:63-75. [PMID: 33356294 DOI: 10.1021/acs.langmuir.0c02354] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We study the spreading dynamics of a sphere-shaped elastic non-Newtonian liquid drop on a spherical substrate in the capillary-driven regime. We use the simplified Phan-Thien-Tanner model to represent the rheology of the elastic non-Newtonian drop. We consider the drop to be a crater on a flat substrate to calculate the viscous dissipation near the contact line. Following the approach compatible with the capillary-viscous force balance, we establish the evolution equation for describing the temporal evolution of the contact line during spreading. We show that the contact line velocity obtained from the theoretical calculation matches well with our experimental observations. Also, as confirmed by the present experimental observations, our analysis deems efficient to capture the phenomenon during the late stage of spreading for which the effect of line tension becomes dominant. An increment in the viscoelastic parameter of the fluid increases the viscous dissipation effect at the contact line. It is seen that the higher dissipation effect leads to an enhancement in the wetting time of the drop on the spherical substrate. Also, we have shown that the elastic nature of the fluid leads to an increment in the dynamic contact angle at any temporal instant as compared to its Newtonian counterpart. Finally, we unveil that the phenomenon of the increasing contact angle results in the time required for the complete wetting of drop, which becomes higher with increasing viscoelasticity of the fluid. This article will fill a gap still affecting the existing literature because of the unavailability of experimental investigations of the spreading of the elastic non-Newtonian drop on a spherical substrate.
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Affiliation(s)
- Sudip Shyam
- Microfluidcs and Microscale Transport Processes Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Harshad Sanjay Gaikwad
- Microfluidcs and Microscale Transport Processes Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Syed Abu Ghalib Ahmed
- Department of Mechanical Engineering, Tezpur University, Napaam, Tezpur, Assam 781048, India
| | - Bibek Chakraborty
- Department of Mechanical Engineering, Tezpur University, Napaam, Tezpur, Assam 781048, India
| | - Pranab Kumar Mondal
- Microfluidcs and Microscale Transport Processes Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
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8
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Wang X, Lin D, Wang Y, Gao S, Yang Y, Wang X. Rebound dynamics of two droplets simultaneously impacting a flat superhydrophobic surface. AIChE J 2020. [DOI: 10.1002/aic.16647] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Xin Wang
- Research Center of Engineering ThermophysicsNorth China Electric Power University Beijing China
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy SourcesNorth China Electric Power University Beijing China
| | - Dian‐Ji Lin
- Research Center of Engineering ThermophysicsNorth China Electric Power University Beijing China
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy SourcesNorth China Electric Power University Beijing China
| | - Yi‐Bo Wang
- Research Center of Engineering ThermophysicsNorth China Electric Power University Beijing China
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy SourcesNorth China Electric Power University Beijing China
| | - Shu‐Rong Gao
- Research Center of Engineering ThermophysicsNorth China Electric Power University Beijing China
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy SourcesNorth China Electric Power University Beijing China
| | - Yan‐Ru Yang
- Research Center of Engineering ThermophysicsNorth China Electric Power University Beijing China
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy SourcesNorth China Electric Power University Beijing China
| | - Xiao‐Dong Wang
- Research Center of Engineering ThermophysicsNorth China Electric Power University Beijing China
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy SourcesNorth China Electric Power University Beijing China
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9
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10
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Wang SY, Wang SL, Yang YR, Wang XD, Lee DJ. High-temperature reactive wetting systems: Role of lattice constant. Chem Eng Sci 2019. [DOI: 10.1016/j.ces.2019.115206] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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11
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Wang H. From Contact Line Structures to Wetting Dynamics. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:10233-10245. [PMID: 31150247 DOI: 10.1021/acs.langmuir.9b00294] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
An important reason for the century-long debate concerning wetting dynamics is the lack of decisive information about the contact line. The contact line cannot be treated as a geometric line but is rather a region with complex structures. The contact line regions have been intensively explored in recent years by utilizing advanced nanoscopic experimental and modeling methods. This feature article summarizes the primary observation results and related modeling progress. A framework is then proposed for understanding the wetting dynamics. Basic questions are raised for future research on the partial wetting of nonvolatile as well as volatile liquids.
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Affiliation(s)
- Hao Wang
- The Laboratory of Heat and Mass Transport at Micro-Nano Scale, College of Engineering , Peking University , Beijing 100871 , China
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12
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Wang J, Cao Y, Xing Y, Li G, Liao Y, Li S, An M. Spreading behavior of oil droplets over polytetrafluoroethylene plates in deionized water. J DISPER SCI TECHNOL 2019. [DOI: 10.1080/01932691.2019.1645025] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Junchao Wang
- Chinese National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology , Xuzhou , Jiangsu , China
- School of Chemical Engineering and Technology, China University of Mining and Technology , Xuzhou , Jiangsu , China
| | - Yijun Cao
- Chinese National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology , Xuzhou , Jiangsu , China
- Henan Province Industrial Technology Research Institution of Resources and Materials, Zhengzhou University , Zhengzhou , Henan , China
| | - Yaowen Xing
- Chinese National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology , Xuzhou , Jiangsu , China
| | - Guosheng Li
- School of Chemical Engineering and Technology, China University of Mining and Technology , Xuzhou , Jiangsu , China
| | - Yinfei Liao
- Chinese National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology , Xuzhou , Jiangsu , China
| | - Shulei Li
- Chinese National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology , Xuzhou , Jiangsu , China
| | - Maoyan An
- Chinese National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology , Xuzhou , Jiangsu , China
- School of Chemical Engineering and Technology, China University of Mining and Technology , Xuzhou , Jiangsu , China
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13
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Wang X, Min Q, Zhang Z, Duan Y. Effect of Moving Contact Line's Curvature on Dynamic Wetting of non-Newtonian Fluids. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:15612-15620. [PMID: 30461284 DOI: 10.1021/acs.langmuir.8b03534] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The curvature of the contact line is always changing with the dynamic wetting condition. Using a modified Wilhelmy plate method and the sessile drop method, this study experimentally investigated the dynamic wetting process of several kinds of Newtonian and non-Newtonian fluids. The results show that the curvature of the moving contact line strongly affects the relationship θD = f( U) for non-Newtonian fluids but has no effect on Newtonian fluids. The effect is more obvious with the stronger non-Newtonian fluids. The theoretical relationship derived from the Navier-Stokes equations established for spontaneous spreading indicates that the moving contact line curvature affects the relationship θD = f( U) for shear-thinning fluids and shear-thickening fluids in a different way, which agrees with the forced wetting experimental results for shear-thinning fluids in both this work and the previous one on the fluid showing shear-thickening rheology. A force balance relation of the braking force and driving force for the moving contact line is used to explain the internal mechanism about how the curvature of the contact line affects θD during wetting process.
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14
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Rongqi S, Qingshun B, Xin H, Aimin Z, Feihu Z. Molecular dynamics simulation of the spreading of the nanosized droplet on a graphene-coated substrate: the effect of the contact line forces. MOLECULAR SIMULATION 2018. [DOI: 10.1080/08927022.2018.1479750] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Shen Rongqi
- School of Mechanical and Electrical Engineering, Harbin Institute of Technology, Harbin, People’s Republic of China
| | - Bai Qingshun
- School of Mechanical and Electrical Engineering, Harbin Institute of Technology, Harbin, People’s Republic of China
| | - He Xin
- School of Mechanical and Electrical Engineering, Harbin Institute of Technology, Harbin, People’s Republic of China
| | - Zhang Aimin
- School of Mechanical and Electrical Engineering, Harbin Institute of Technology, Harbin, People’s Republic of China
| | - Zhang Feihu
- School of Mechanical and Electrical Engineering, Harbin Institute of Technology, Harbin, People’s Republic of China
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15
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Lin L, Hui S, Lu G, Wang SL, Wang XD, Lee DJ. Molecular dynamics study of high temperature wetting kinetics for Al/NiAl and Al/Ni3Al systems: Effects of grain boundaries. Chem Eng Sci 2017. [DOI: 10.1016/j.ces.2017.09.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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16
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Dewetting kinetics of metallic liquid films: Competition between unbalanced Young’s force and dissolutive reaction. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.09.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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17
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Foroutan M, Zahedi H, Esmaeilian F. Temperature effects on spreading of water nano-droplet on poly(methyl methacrylate): A molecular dynamics simulation study. ACTA ACUST UNITED AC 2017. [DOI: 10.1002/polb.24409] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Masumeh Foroutan
- Department of Physical Chemistry, School of Chemistry, College of Science; University of Tehran; Tehran 1417614418 Iran
| | - Hojat Zahedi
- Department of Physical Chemistry, School of Chemistry, College of Science; University of Tehran; Tehran 1417614418 Iran
| | - Farshad Esmaeilian
- Department of Physical Chemistry, School of Chemistry, College of Science; University of Tehran; Tehran 1417614418 Iran
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18
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Molecular dynamics simulations on dissolutive wetting of Al–Ni alloy droplets on NiAl substrate. J Taiwan Inst Chem Eng 2017. [DOI: 10.1016/j.jtice.2017.03.035] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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19
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Noble BA, Mate CM, Raeymaekers B. Spreading Kinetics of Ultrathin Liquid Films Using Molecular Dynamics. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:3476-3483. [PMID: 28319395 DOI: 10.1021/acs.langmuir.7b00334] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Ultrathin liquid films play a critical role in numerous engineering applications. Although crucial to the design and application of ultrathin liquid films, the physical mechanisms that govern spreading on the molecular scale are not well-understood, and disagreement among experiments, simulations, and theory remains. We use molecular dynamics simulations to quantify the speed at which the edge of a polymer droplet advances on a flat substrate as a function of various environmental and design parameters. We explain the physical mechanisms that drive and inhibit spreading, identify different spreading regimes, and clarify transitions between spreading regimes. We demonstrate that the edge of a droplet spreads according to a power law with two distinct regimes, which we attribute to competing physical mechanisms: a pressure difference in the liquid droplet and molecule entanglement. This research unifies many years of liquid spreading research and has implications for systems that involve designing complex ultrathin liquid films.
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Affiliation(s)
- Brooklyn A Noble
- Department of Mechanical Engineering, University of Utah , Salt Lake City, Utah 84112, United States
| | | | - Bart Raeymaekers
- Department of Mechanical Engineering, University of Utah , Salt Lake City, Utah 84112, United States
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Lu G, Wang XD, Duan YY. A Critical Review of Dynamic Wetting by Complex Fluids: From Newtonian Fluids to Non-Newtonian Fluids and Nanofluids. Adv Colloid Interface Sci 2016; 236:43-62. [PMID: 27521099 DOI: 10.1016/j.cis.2016.07.004] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 07/02/2016] [Accepted: 07/20/2016] [Indexed: 01/22/2023]
Abstract
Dynamic wetting is an important interfacial phenomenon in many industrial applications. There have been many excellent reviews of dynamic wetting, especially on super-hydrophobic surfaces with physical or chemical coatings, porous layers, hybrid micro/nano structures and biomimetic structures. This review summarizes recent research on dynamic wetting from the viewpoint of the fluids rather than the solid surfaces. The reviewed fluids range from simple Newtonian fluids to non-Newtonian fluids and complex nanofluids. The fundamental physical concepts and principles involved in dynamic wetting phenomena are also reviewed. This review focus on recent investigations of dynamic wetting by non-Newtonian fluids, including the latest experimental studies with a thorough review of the best dynamic wetting models for non-Newtonian fluids, to illustrate their successes and limitations. This paper also reports on new results on the still fledgling field of nanofluid wetting kinetics. The challenges of research on nanofluid dynamic wetting is not only due to the lack of nanoscale experimental techniques to probe the complex nanoparticle random motion, but also the lack of multiscale experimental techniques or theories to describe the effects of nanoparticle motion at the nanometer scale (10(-9) m) on the dynamic wetting taking place at the macroscopic scale (10(-3) m). This paper describes the various types of nanofluid dynamic wetting behaviors. Two nanoparticle dissipation modes, the bulk dissipation mode and the local dissipation mode, are proposed to resolve the uncertainties related to the various types of dynamic wetting mechanisms reported in the literature.
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Wu CJ, Huang CJ, Jiang S, Sheng YJ, Tsao HK. Superhydrophilicity and spontaneous spreading on zwitterionic surfaces: carboxybetaine and sulfobetaine. RSC Adv 2016. [DOI: 10.1039/c6ra01825d] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Wetting behavior of zwitterionic surfaces fabricated by grafting sulfobetaine silane (SBSi) and carboxybetaine silane (CBSi) on glass slides.
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Affiliation(s)
- Cyuan-Jhang Wu
- Department of Chemical and Materials Engineering
- National Central University
- Jhongli 320
- Taiwan
| | - Chun-Jen Huang
- Department of Chemical and Materials Engineering
- National Central University
- Jhongli 320
- Taiwan
- Graduate Institute of Biomedical Engineering
| | - Shaoyi Jiang
- Department of Chemical Engineering
- University of Washington
- Seattle
- USA
| | - Yu-Jane Sheng
- Department of Chemical Engineering
- National Taiwan University
- Taipei 106
- Taiwan
| | - Heng-Kwong Tsao
- Department of Chemical and Materials Engineering
- National Central University
- Jhongli 320
- Taiwan
- Department of Physics
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A Comprehensive Review on Measurement and Correlation Development of Capillary Pressure for Two-Phase Modeling of Proton Exchange Membrane Fuel Cells. J CHEM-NY 2015. [DOI: 10.1155/2015/876821] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Water transport and the corresponding water management strategy in proton exchange membrane (PEM) fuel cells are quite critical for the improvement of the cell performance. Accuracy modeling of water transport in porous electrodes strongly depends on the appropriate constitutive relationship for capillary pressure which is referred to aspc-scorrelation, wherepcis the capillary pressure andsis the fraction of saturation in the pores. In the present PEM fuel cell two-phase models, the Leverett-Udellpc-scorrelation is widely utilized which is proposed based on fitting the experimental data for packed sands. However, the size and structure of pores for the commercial porous electrodes used in PEM fuel cells differ from those for the packed sands significantly. As a result, the Leverett-Udell correlation should be improper to characterize the two-phase transport in the porous electrodes. In the recent decade, many efforts were devoted to measuring the capillary pressure data and developing newpc-scorrelations. The objective of this review is to review the most significant developments in recent years concerning the capillary pressure measurements and the developedpc-scorrelations. It is expected that this review will be beneficial to develop the improved PEM fuel cell two-phase model.
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Ahmed G, Sellier M, Lee YC, Jermy M, Taylor M. Modeling the spreading and sliding of power-law droplets. Colloids Surf A Physicochem Eng Asp 2013. [DOI: 10.1016/j.colsurfa.2013.05.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Spreading of a non-Newtonian liquid drop over a homogeneous rough surface. Colloids Surf A Physicochem Eng Asp 2013. [DOI: 10.1016/j.colsurfa.2012.11.068] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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26
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Energy-based model for capillary spreading of power-law liquids on a horizontal plane. Colloids Surf A Physicochem Eng Asp 2012. [DOI: 10.1016/j.colsurfa.2012.04.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Min Q, Duan YY, Wang XD, Liang ZP, Si C. Does macroscopic flow geometry influence wetting dynamic? J Colloid Interface Sci 2011; 362:221-7. [DOI: 10.1016/j.jcis.2011.06.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 06/08/2011] [Accepted: 06/09/2011] [Indexed: 10/18/2022]
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Liang ZP, Wang XD, Duan YY, Min Q, Wang C, Lee DJ. Dynamic wetting of non-newtonian fluids: multicomponent molecular-kinetic approach. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:14594-14599. [PMID: 20795633 DOI: 10.1021/la102041q] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Hydrodynamic models are generally applied to describe the dynamic wetting of newtonian or non-newtonian fluids on a solid surface. Conversely, the molecular-kinetic paradigm is only utilized for spreading newtonian fluids while considering the movement of a contact line as a molecular hopping process. This study extended the molecular-kinetic paradigm to the wetting behavior of non-newtonian fluids, while assuming there are n fluid components at the contact line regime interacting simultaneously with a solid surface during front movement. The limiting cases of the derived model at slow and fast moving speeds were discussed. Moreover, the derived model was validated based on dynamic contact angle data of three carboxymethylcellulose (CMC) aqueous solutions measured using the force-balance method. Best-fit parameters were used to interpret the wetting dynamics of CMC solutions.
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Affiliation(s)
- Zhan-Peng Liang
- Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084, China
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Spreading of completely wetting, non-Newtonian fluids with non-power-law rheology. J Colloid Interface Sci 2010; 348:250-4. [DOI: 10.1016/j.jcis.2010.04.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Revised: 03/22/2010] [Accepted: 04/08/2010] [Indexed: 11/21/2022]
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Liang ZP, Wang XD, Lee DJ, Peng XF, Su A. Spreading dynamics of power-law fluid droplets. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:464117. [PMID: 21715881 DOI: 10.1088/0953-8984/21/46/464117] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
This paper aims at providing a summary of the theoretical models available for non-Newtonian fluid spreading dynamics. Experimental findings and model predictions for a Newtonian fluid spreading test are briefly reviewed. Then how the complete wetting and partial wetting power-law fluids spread over a solid substrate is examined. The possible extension of Newtonian fluid models to power-law fluids is also discussed.
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Affiliation(s)
- Zhan-Peng Liang
- Lab of Phase Change and Interfacial Transport Phenomena, Department of Thermal Engineering, Tsinghua University, Beijing 100084, People's Republic of China
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