1
|
Zhang S, Zhao L, Yu M, Guo J, Liu C, Zhu C, Zhao M, Huang Y, Zheng Y. Measurement Methods for Droplet Adhesion Characteristics and Micrometer-Scale Quantification of Contact Angle on Superhydrophobic Surfaces: Challenges and Opportunities. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:9873-9891. [PMID: 38695884 DOI: 10.1021/acs.langmuir.3c03967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2024]
Abstract
Inspired by nature, superhydrophobic surfaces have been widely studied. Usually the wettability of a superhydrophobic surface is quantified by the macroscopic contact angle. However, this method has various limitations, especially for precision micro devices with superhydrophobic surfaces, such as biomimetic artificial compound eyes and biomimetic water strider robots. These precision micro devices with superhydrophobic surfaces proposed a higher demand for the quantification of contact angles, requiring contact angle quantification technology to have micrometer-scale measurement capabilities. In this review, it is proposed to achieve micrometer-scale quantification of superhydrophobic surface contact angles through droplet adhesion characteristics (adhesion force and contact radius). Existing contact angle quantification techniques and droplet characteristics' measurement methods were described in detail. The advancement of micrometer-scale quantification technology for the contact angle of superhydrophobic surfaces will enhance our understanding of superhydrophobic surfaces.
Collapse
Affiliation(s)
- Shiyu Zhang
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, People's Republic of China
| | - Lingzhe Zhao
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, People's Republic of China
| | - Meike Yu
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, People's Republic of China
| | - Jinwei Guo
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, People's Republic of China
| | - Chuntian Liu
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, People's Republic of China
| | - Chunyuan Zhu
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, People's Republic of China
| | - Meirong Zhao
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, People's Republic of China
| | - Yinguo Huang
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, People's Republic of China
| | - Yelong Zheng
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, People's Republic of China
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
Yang L, Liu X, Wang J, Zhang P. An Experimental Study on Complete Droplet Rebound from Soft Surfaces: Critical Weber Numbers, Maximum Spreading, and Contact Time. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:2165-2173. [PMID: 38232322 DOI: 10.1021/acs.langmuir.3c03126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Droplet impact on soft surfaces (PDMS) was experimentally studied with particular interest in the complete rebound of droplets. This study focuses on the effect of liquid viscosity and the elastic modulus of the substrate on the critical rebound Weber number, maximum spreading, and contact time. Specifically, the lower and upper critical Weber numbers increase with an increasing droplet viscosity. With decreasing PDMS elastic modulus, the upper critical Weber number increases, while the lower critical Weber number decreases. The PDMS elastic modulus does not significantly affect the maximum spreading time and contact time. An interesting phenomenon of discontinuous contact time was experimentally observed and was theoretically interpreted.
Collapse
Affiliation(s)
- Lei Yang
- College of Civil and Transportation Engineering, Shenzhen University, Shenzhen 518060, China
| | - Ximiao Liu
- College of Civil and Transportation Engineering, Shenzhen University, Shenzhen 518060, China
| | - Jinyang Wang
- State Key Laboratory of Engines, Tianjin University, Tianjin 300350, PR China
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon Tong, Kowloon 999077, Hong Kong
| | - Peng Zhang
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon Tong, Kowloon 999077, Hong Kong
| |
Collapse
|
4
|
Chen X, Zhang LZ, Wang YF, Jin JX, Wang YB, Yang YR, Gao SR, Zheng SF, Wang XD, Lee DJ. Effect of Asymmetry on the Contact Time of Droplet Impact on Superhydrophobic Cylindrical Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:19037-19047. [PMID: 38096493 DOI: 10.1021/acs.langmuir.3c03212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
Reducing the contact time during the droplet impact on the surface is crucial for anti-icing, self-cleaning, and heat transfer optimization applications. This study aims to minimize the contact time by modifying the surface curvature to create an asymmetric impact process. Our experiments showed that the increase in Weber numbers (We) and the decrease in the ratio of surface diameter to droplet diameter (D*) intensify the asymmetry of the impact process, yielding four distinct rebound modes. Low asymmetry observes the liquid retract toward the central point (Rebound Modes 1 and 2), whereas high asymmetry yields a wing-like rebound (Rebound Modes 3 and 4). In Rebound Mode 1, increased asymmetry would lead to more extended contact due to the prolonged waiting period. Conversely, the reduction in contact time in Rebound Mode 2 occurs due to increased asymmetry with no waiting period. For Rebound Modes 3 and 4, the retraction time could be divided into three stages, generated by two liquid detachment modes from the surface. Analysis reveals that an increased asymmetry would reduce the retraction time during the first stage but prolong it during the third stage, with no significant effects on the second. Four correlations, each pertaining to a distinct impact mode, are proposed based on these analyses to describe the contact time concerning We and D* for droplets impacting a superhydrophobic cylindrical surface.
Collapse
Affiliation(s)
- Xu Chen
- 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
| | - 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
| | - 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
| | - Jia-Xin Jin
- 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-Bo 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
| | - 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
| | - 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
| | - 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
| |
Collapse
|
5
|
Chen X, Wang YF, Yang YR, Wang XD, Lee DJ. Contact Time of Droplet Impact on Superhydrophobic Cylindrical Surfaces with a Ridge. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:18644-18653. [PMID: 38051278 DOI: 10.1021/acs.langmuir.3c03149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
This study investigates whether adding ridges to a superhydrophobic cylindrical surface can reduce contact times compared to those of ridged flat or cylindrical surfaces, inspired by the shortened contact time achieved by adding ridges to flat surfaces. The study focuses on studying azimuthal ridges on the cylinder through experimentation, emphasizing the impact dynamics and contact time characteristics under varying We (Weber number) and D* (dimensionless droplet diameter). Within the ultralow Weber number range (ULWR), low Weber number range (LWR), and medium Weber number range (MWR), the contact time is longer than on ridged flat surfaces. In the high Weber number range (HWR), the opposite is observed: increased inertial forces lead to the rupture of the liquid film above the ridges due to Rayleigh-Plateau instability. As a result, the primary droplet splits into two sections with curvature effects promoting its recoiling and rebounding. This study introduces a criterion, defined as C = We/D*, and finds that when C exceeds 2.42, not only is the contact time shorter than on ridged flat or cylindrical surfaces, but it also further decreases with an increase in We or a decrease in D*. The contact time characteristics observed in the HWR offer potential applications in areas such as anti-icing.
Collapse
Affiliation(s)
- Xu Chen
- 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
| | - 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, 999077 Kowloon, Hong Kong
- Department of Chemical Engineering & Materials Science, Yuan-Ze University, Chungli 320, Taiwan
| |
Collapse
|
6
|
Hu Z, Chu F, Shan H, Wu X, Dong Z, Wang R. Understanding and Utilizing Droplet Impact on Superhydrophobic Surfaces: Phenomena, Mechanisms, Regulations, Applications, and Beyond. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023:e2310177. [PMID: 38069449 DOI: 10.1002/adma.202310177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 11/13/2023] [Indexed: 12/19/2023]
Abstract
Droplet impact is a ubiquitous liquid behavior that closely tied to human life and production, making indispensable impacts on the big world. Nature-inspired superhydrophobic surfaces provide a powerful platform for regulating droplet impact dynamics. The collision between classic phenomena of droplet impact and the advanced manufacture of superhydrophobic surfaces is lighting up the future. Accurately understanding, predicting, and tailoring droplet dynamic behaviors on superhydrophobic surfaces are progressive steps to integrate the droplet impact into versatile applications and further improve the efficiency. In this review, the progress on phenomena, mechanisms, regulations, and applications of droplet impact on superhydrophobic surfaces, bridging the gap between droplet impact, superhydrophobic surfaces, and engineering applications are comprehensively summarized. It is highlighted that droplet contact and rebound are two focal points, and their fundamentals and dynamic regulations on elaborately designed superhydrophobic surfaces are discussed in detail. For the first time, diverse applications are classified into four categories according to the requirements for droplet contact and rebound. The remaining challenges are also pointed out and future directions to trigger subsequent research on droplet impact from both scientific and applied perspectives are outlined. The review is expected to provide a general framework for understanding and utilizing droplet impact.
Collapse
Affiliation(s)
- Zhifeng Hu
- Research Center of Solar Power and Refrigeration, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Fuqiang Chu
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - He Shan
- Research Center of Solar Power and Refrigeration, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xiaomin Wu
- Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, Beijing, 100084, China
| | - Zhichao Dong
- CAS Key Laboratory of Bio-inspired Materials and Interfacial Sciences, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ruzhu Wang
- Research Center of Solar Power and Refrigeration, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| |
Collapse
|
7
|
Zhang LZ, Chen X, Wang YF, Yang YR, Zheng SF, Lee DJ, Wang XD. Contact Time of a Droplet Off-Centered Impacting a Superhydrophobic Cylinder. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:16023-16034. [PMID: 37916520 DOI: 10.1021/acs.langmuir.3c02154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2023]
Abstract
Extensive research has shown that a superhydrophobic cylindrical substrate could lead to a noncircumferential symmetry of an impacting droplet, reducing the contact time accordingly. It is of practical significance in applications, such as anti-icing, anticorrosion, and antifogging. However, few accounts have adequately addressed the off-centered impact of the droplet, despite it being more common in practice. This work investigates the dynamic behavior of a droplet off-centered impacting a superhydrophobic cylinder via the lattice Boltzmann method. The effect of the off-centered distance is primarily discussed for droplets taking various Weber numbers and cylinder sizes. The results show that the imposition of an off-center distance can further disrupt the droplet symmetry during the impact. As the off-center distance increases, the droplet movement is gradually tilted toward the offset side until it tangentially passes the cylinder side, resulting in a direct dripping mode. The dynamic features, focusing mainly on maximum spreading in the axial direction and contact time, are specifically explored. A quantitative model of the maximum spreading factor is proposed based on the equivalent transformation from the off-center impact into oblique hitting, considering the full range of off-centered distance. A preliminary contact time model is established for droplet off-centered impacting superhydrophobic cylinders by substituting the maximum spreading and the effective velocity of the liquid moving. This work aims to make an original contribution to the fundamental knowledge of droplet impact and could be of value for related applications.
Collapse
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
| | - Xu Chen
- 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
| | - 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
| | - 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
| |
Collapse
|
8
|
Bandyopadhyay S, Bakli C, Mukherjee R, Chakraborty S. Damped Oscillatory Dynamics of a Drop Impacting over Oil-Infused Slippery Interfaces─Does the Oil Viscosity Slow it Down? LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:12826-12834. [PMID: 37642554 DOI: 10.1021/acs.langmuir.3c01689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
A liquid drop impacting on a soft surface is known to exhibit fascinating dynamics that is distinctive from its bounce-back atop a rigid surface. However, while the early spreading of the drop subsequent to its immediate impact with a lubricating liquid layer appears to be reasonably well understood, the later events of retraction and eventual stabilization appear to be poorly addressed. Here, we bring out the nontrivial confluence of the solid substrate wettability and the liquid layer viscosity toward modulating the post-collision dynamics of an impinging liquid drop on a viscous oil-infused surface during its later phase of settlement before arriving at an equilibrium state. Our results reveal that despite an intuitive analogy with the classical phenomenon of damped oscillation, the drop, during its later stages of motion, undergoes dynamical events that may be nontrivially dictated by not only the relative viscosity of the impacting drop and the liquid layer but also the intrinsic wettability of the solid substrate, governing its post-impact settlement via a sequel of spreading-retraction cycles. As a consequence, the viscous liquid layer, instead of providing additional damping, may nonintuitively reduce the effective viscous dissipation so as to hasten the drop's final settlement. These results may turn out to be critical in designing engineered surfaces for tuning the movement of drops in a preferential pathway, bearing decisive implications in the functionalities of liquid lenses, inkjet printing, spray coating and cooling, and several other emerging applications in the realm of lubricated fluidic interfaces.
Collapse
Affiliation(s)
- Saumyadwip Bandyopadhyay
- Advanced Technology Development Centre, Indian Institute of Technology Kharagpur, Kharagpur 721 302, West Bengal, India
| | - Chirodeep Bakli
- School of Energy Science and Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, West Bengal, India
| | - Rabibrata Mukherjee
- Advanced Technology Development Centre, Indian Institute of Technology Kharagpur, Kharagpur 721 302, West Bengal, India
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, West Bengal, India
| | - Suman Chakraborty
- Advanced Technology Development Centre, Indian Institute of Technology Kharagpur, Kharagpur 721 302, West Bengal, India
- Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, West Bengal, India
| |
Collapse
|
9
|
Dai Q, Yue C, Huang W, Wang X. Droplets impact on rotating cylinders. Chem Eng Sci 2023. [DOI: 10.1016/j.ces.2023.118669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
|
10
|
Zhang LZ, Chen X, Yang YR, Wang XD. Impact Dynamics of a Droplet on Superhydrophobic Cylinders Structured with a Macro Ridge. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:6375-6386. [PMID: 37092810 DOI: 10.1021/acs.langmuir.3c00067] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Reducing the contact time of a droplet hitting a solid surface is crucial for many situations. In this work, the dynamic behavior of a low-viscosity droplet on a superhydrophobic surface, which consists of a cylindrical substrate and a macro ridge placed axially on the peak, was numerically investigated via the lattice Boltzmann method. The focus was given to the spreading and the detaching morphology of the droplet at the Weber number We = 0.84-37.8 and the cylinder-to-droplet radius ratio R* = 0.57-5.71. The ridge is found to redistribute the droplet mass and affect the impact outcomes, as well as the contact time. For each R*, a jug rebound, a stretched rebound straddling the ridge, and a split detachment occur sequentially with the increasing We. When R* does not exceed 1.71, the contact time decreases continuously with the increase in We. With R* being taken between 1.71 and 5.14, the contact time initially reduces with We and plateaus after We reaches 10.3. Once R* exceeds 5.14, the split droplets may present as a bestriding shape at We > 30.3 rather than the regular jug shape with a small We. The contact time would be decreased to a second plateau in this case. In most cases, the contact time can be shortened effectively for the droplet on a ridged cylinder compared with that of a smooth cylinder.
Collapse
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
| | - Xu Chen
- 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
| | - 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
| |
Collapse
|
11
|
Xin J, Jia K, Yu L, Li H, Ning J, Zheng X, Wu H, Liu X, Huang L, Wen W. Controlling high-speed droplet splashing and superspreading behavior on anisotropic superhydrophobic leaf surfaces by ecofriendly Pseudogemini surfactants. PEST MANAGEMENT SCIENCE 2023. [PMID: 36994611 DOI: 10.1002/ps.7485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 02/03/2023] [Accepted: 03/30/2023] [Indexed: 06/19/2023]
Abstract
BACKGROUND Efficient deposition of high-speed droplets on superhydrophobic leaf surfaces remains an important challenge. For anisotropic wired superhydrophobic leaf surfaces, the splashing phenomenon is especially serious because it leads to the low effective utilization of pesticides by biological targets. The lost pesticides cause serious ecological environment pollution, therefore there is an urgent need to develop a green and sustainable cost-effective strategy to achieve efficient deposition of high-speed droplets on anisotropic superhydrophobic leaf surfaces at low dosage. RESULTS One type of green pseudogemini surfactant is constructed based on fatty acids and hexamethylenediamine by electrostatic interaction to control the splashing and spreading of high-speed droplets on superhydrophobic surfaces. The formed surfactant can not only achieve complete inhibition of the bouncing of droplets, but also promote rapid spreading on superhydrophobic leaf surfaces at very low usage. The efficient deposition and superspreading phenomenon are attributed to the rapid migration and adsorption of the surfactant from the dynamic spherical micelles at the newly formed solid-liquid interface, the network-like aggregated spherical micelles, and the Marangoni effect caused by the surface tension gradient. Moreover, the surfactant shows an excellent synergistic effect with herbicides to control weeds by inhibiting droplet splashing. CONCLUSION This work provides a simpler, more effective and sustainable approach to utilize aggregated spherical micelles rather than conventional vesicles or wormlike micelles to improve the droplet deposition on superhydrophobic leaf surfaces and reduce the impact of surfactants and pesticides on the ecological environment.
Collapse
Affiliation(s)
- Jinlan Xin
- Guangdong Provincial Key Laboratory of Industrial Surfactant, Institute of Chemical Engineering, Guangdong Academy of Sciences, Guangzhou, P. R. China
| | - Kangle Jia
- Guangdong Provincial Key Laboratory of Industrial Surfactant, Institute of Chemical Engineering, Guangdong Academy of Sciences, Guangzhou, P. R. China
| | - Longfei Yu
- Guangdong Provincial Key Laboratory of Industrial Surfactant, Institute of Chemical Engineering, Guangdong Academy of Sciences, Guangzhou, P. R. China
| | - Huanling Li
- Guangdong Provincial Key Laboratory of Industrial Surfactant, Institute of Chemical Engineering, Guangdong Academy of Sciences, Guangzhou, P. R. China
| | - Junhua Ning
- Guangdong Provincial Key Laboratory of Industrial Surfactant, Institute of Chemical Engineering, Guangdong Academy of Sciences, Guangzhou, P. R. China
| | - Xiaoshan Zheng
- Guangdong Provincial Key Laboratory of Industrial Surfactant, Institute of Chemical Engineering, Guangdong Academy of Sciences, Guangzhou, P. R. China
| | - Haifu Wu
- Guangdong Provincial Key Laboratory of Industrial Surfactant, Institute of Chemical Engineering, Guangdong Academy of Sciences, Guangzhou, P. R. China
| | - Xingxing Liu
- Guangdong Provincial Key Laboratory of Industrial Surfactant, Institute of Chemical Engineering, Guangdong Academy of Sciences, Guangzhou, P. R. China
| | - Linjia Huang
- Guangdong Provincial Key Laboratory of Industrial Surfactant, Institute of Chemical Engineering, Guangdong Academy of Sciences, Guangzhou, P. R. China
| | - Wu Wen
- Guangdong Provincial Key Laboratory of Industrial Surfactant, Institute of Chemical Engineering, Guangdong Academy of Sciences, Guangzhou, P. R. China
| |
Collapse
|
12
|
Steerable directional bouncing and contact time reduction of impacting droplets on superhydrophobic stepped surfaces. J Colloid Interface Sci 2023; 629:1032-1044. [DOI: 10.1016/j.jcis.2022.09.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 08/25/2022] [Accepted: 09/04/2022] [Indexed: 11/19/2022]
|
13
|
Adverse impact of macro-textured superhydrophobicity on contact time reduction at high Weber numbers. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.129948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
14
|
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.
Collapse
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
| |
Collapse
|
15
|
Huang W, Huang J, Guo Z, Liu W. Icephobic/anti-icing properties of superhydrophobic surfaces. Adv Colloid Interface Sci 2022; 304:102658. [PMID: 35381422 DOI: 10.1016/j.cis.2022.102658] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 03/26/2022] [Accepted: 03/26/2022] [Indexed: 01/31/2023]
Abstract
In the winter, icing on solid surfaces is a typical occurrence that may create a slew of hassles and even tragedies. Anti-icing surfaces are one of the effective solutions for this kind of problem. The roughness of a superhydrophobic surface traps air and weakens the contact between the solid surface and liquid water, allowing water droplets to be removed before freezing. At present, the conventional anti-icing methods including mechanical or thermal technology are not only surface structure unfriendly but also have the obsessions of low efficiency, high energy consumption and high manufacturing costs. Hence, developing a way to remove ice by just modifying the surface shape or chemical composition with a low surface energy is extremely desirable. Numerous attempts have been made to investigate the evolution of ice nucleation and icing on superhydrophobic surfaces under the direction of the ice nucleation hypothesis. In this paper, the research progress of ice nucleation in recent years is reviewed from theoretical and application. The icephobic surfaces are described using the wettability and classical nucleation theories. The benefits and drawbacks of anti-icing superhydrophobic surface are summarized, as well as deicing methods. Finally, several applications of ice phobic materials are illustrated, and some problems and challenges in the research field are discussed. We believed that this review will be useful in guiding future water freezing initiatives.
Collapse
|
16
|
Bao Z, Zeng A, Gao T, Gao Y, He Q, Huang Y, Chou J, Yu L, Zhang C, Du F. Controlling impact behavior on superhydrophobic surfaces for droplets of nonionic surfactants by tailoring hydrophilic chain length. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2021.117071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
17
|
Du J, Wang X, Li Y, Min Q. Maximum spreading of liquid droplets impact on concentric ring-textured surfaces: Theoretical analysis and numerical simulation. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.127647] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
18
|
Bouncing dynamics of a nanodroplet impacting a superhydrophobic surface under perpendicular electric fields. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.127617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
19
|
Li T, Wu Y. Impact Dynamics of Nanodroplets on V-Shaped Substrates: Asymmetrical Behavior and Fast-Rebound Dynamics. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:13170-13178. [PMID: 34699717 DOI: 10.1021/acs.langmuir.1c02488] [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
Controlling the drop impact behaviors plays an important role in both designing surface functional materials and improving industrial techniques. Here, the impact dynamics of nanodroplets on "V-shaped" substrates is studied, which is manifested as asymmetrical spreading and retraction behaviors that could be weakened by increasing the angles of the "V" shape, accompanied by the evolution of the shape from leaf-like, stripe-like, to dumbbell-like at v = 20 Å/ps. When v increases to 40 Å/ps, the previously deposited nanodroplets could be transformed to a rebound one at α = 60 and 90°, which is ascribed to the combined effect of the confinement conditions and the extrusion force. Furthermore, an impact behavior map as a function of impact velocity and angle is depicted, which suggests that a decrease in angles or an increase in the impact velocity is likely to cause the nanodroplets to rebound. More importantly, the results give visible evidence that compared to the flat substrates, the V-shaped structure is advantageous for achieving a fast-rebound behavior even at a low speed of impact, which should be good news for practical applications in many multidisciplinary fields, such as self-cleaning, anti-icing/fogging, pollution prevention, energy storage, and so forth.
Collapse
Affiliation(s)
- Tao Li
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, China
| | - Yan Wu
- Department of Chemistry, Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong 999077, China
| |
Collapse
|
20
|
Zhang LZ, Wang YB, Gao SR, Lin DJ, Yang YR, Wang XD, Lee DJ. Re-touch rebound patterns and contact time for a droplet impacting a superhydrophobic cylinder. J Taiwan Inst Chem Eng 2021. [DOI: 10.1016/j.jtice.2021.07.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
21
|
Choi W, Yun S. Symmetry-Breaking Drop Bouncing on Superhydrophobic Surfaces with Continuously Changing Curvatures. Polymers (Basel) 2021; 13:polym13172940. [PMID: 34502980 PMCID: PMC8434175 DOI: 10.3390/polym13172940] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 11/29/2022] Open
Abstract
Controlling the residence time of drops on the solid surface is related to a wide spectrum of engineering applications, such as self-cleaning and anti-icing. The symmetry-breaking dynamics induced by the initial drop shape can promote drop bouncing. Here, we study the bouncing features of spherical and ellipsoidal drops on elliptical surfaces that continuously change curvatures inspired by natural succulent leaves. The bounce characteristics highly depend on the geometric relations between the ellipsoidal drops and curved surfaces. Numerical results show that ellipsoidal shapes of the drops amplify asymmetries of the mass and momentum in synergy with an influence of the surface curvature during the impact, which is verified by experiments. Effects of the surface anisotropy and drops’ ellipticity on the residence time are investigated under various surface morphologies and Weber numbers. The residence time is closely associated with an initial surface curvature at the apex. The underlying principle of modifying the residence time via the drops’ ellipticity and initial surface curvature is elucidated based on momentum asymmetry. The understanding of the bouncing features on curved surfaces will offer practical implications for enhanced heat transfer performances and controlled water repellency, etc.
Collapse
|
22
|
Fast droplet bouncing induced by asymmetric spreading on concave superhydrophobic surfaces. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.126588] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
23
|
Tian Y, Wang H, Zhou X, Deng Q, Zhu X, Chen R, Ding Y, Liao Q. A combined experimental and numerical study on droplet-impact induced breakup and ejection behaviors in vertical electric field. Chem Eng Sci 2021. [DOI: 10.1016/j.ces.2021.116636] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
24
|
Xie H, Xu WH, Jia SH, Wu T. Tunable fabrication of biomimetic polypropylene nanopillars with robust superhydrophobicity and antireflectivity. NANOTECHNOLOGY 2021; 32:395301. [PMID: 34126610 DOI: 10.1088/1361-6528/ac0b18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 06/14/2021] [Indexed: 06/12/2023]
Abstract
The fine nanopillars on the natural cicada wing, which exhibits outstanding superhydrophobicity and anti-reflectivity, are carefully observed and analyzed. Here, a promising strategy by combining anodic aluminum oxide template and hot embossing is proposed for rapidly and efficiently mimicking the orderly and densely arranged nanopillars on the cicada wing surface to polypropylene (PP) surfaces. By adjusting the compression pressure, the nanostructures on the PP replica surface gradually evolve from nanoprotrusion-like features to nanopillar-like features so that a gradient wetting behavior from hydrophilicity to hydrophobicity and further to superhydrophobicity appears on the PP replica surfaces. Specifically, the biomimetic PP replica surface exhibits a contact angle of 159 ± 3° and a rolling angle of 8 ± 3° at a compression pressure of 15 MPa. Moreover, the biomimetic PP replica surface can stabilize its superhydrophobic state under a 1.96 kPa external pressure during the dynamic droplet impact. Besides robust dynamic superhydrophobicity, the biomimetic PP replica surface also demonstrated excellent anti-reflectivity because of the gradually changed effective refractive index. Therefore, the biomimetic PP replica inherits both the superhydrophobicity and anti-reflectivity of the natural cicada wing, which makes the products can effectively reduce the external damage when applied to agricultural films, dustproof films, and packaging materials.
Collapse
Affiliation(s)
- Heng Xie
- School of Chemistry and Chemical Engineering, Huazhong University of Science & Technology, Wuhan, Hubei, 430074, People's Republic of China
| | - Wen-Hua Xu
- Guangdong Provincial Key Laboratory of Technique and Equipment for Macromolecular Advanced Manufacturing, South China University of Technology, Guangzhou, Guangdong, 510640, People's Republic of China
| | - Shun-Heng Jia
- Guangdong Provincial Key Laboratory of Technique and Equipment for Macromolecular Advanced Manufacturing, South China University of Technology, Guangzhou, Guangdong, 510640, People's Republic of China
| | - Ting Wu
- Guangdong Provincial Key Laboratory of Technique and Equipment for Macromolecular Advanced Manufacturing, South China University of Technology, Guangzhou, Guangdong, 510640, People's Republic of China
| |
Collapse
|
25
|
Li T, Zhang L, Li M, Yan M, Ni E, Ruan Y, Li H. Non-retraction rebound of the impacting nano-droplets. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115521] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
26
|
Xie H, Xu WH, Fang C, Wu T. Efficient and economical approach for flexible photothermal icephobic copper mesh with robust superhydrophobicity and active deicing property. SOFT MATTER 2021; 17:1901-1911. [PMID: 33416069 DOI: 10.1039/d0sm01930e] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Facing various problems caused by icing in daily life, preparing photothermal deicing materials with wide applicability in high efficiency and low cost is not only a current research hotspot but also a great challenge. Herein, an economical spray-coating method is applied to prepare high-efficiency flexible photothermal icephobic copper mesh using micro silicon carbide (SiC) particles as photothermal conversion material and nano silica (SiO2) particles as a surface superhydrophobic modifier. Owing to the excellent hierarchical micro-nanostructures, the SiC/SiO2 coated copper mesh exhibits a water contact angle (CA) of 162 ± 2° and a sliding angle (SA) of 3 ± 2°. Interestingly, the coated copper mesh exhibits exceptional mechanical durability against water droplet and water flow impact, repeated bending-twisting and tape-peeling. Benefitting from the robust superhydrophobicity, the SiC/SiO2 coating on the copper mesh can significantly delay the freezing time of the droplets and reduce the ice adhesion strength. Furthermore, the coated copper mesh well retains the good photothermal conversion and thermal conductivity properties of the micro SiC particles. Under NIR irradiation, the surface temperature of the coated copper mesh placed on the ice layer can increase by 35.3 °C in 220 s, so that it can rapidly melt the accumulated frost and ice layer on the inner wall of the refrigerator. The presented flexible photothermal icephobic copper mesh exhibits enormous potential when applied to remove ice from apparatus that is accessible, such as road, overhead transmission lines and power networks owing to its flexibility, economy, and high energy efficiency.
Collapse
Affiliation(s)
- Heng Xie
- School of Chemistry and Chemical Engineering, Huazhong University of Science &Technology, Wuhan, Hubei 430074, China
| | - Wen-Hua Xu
- Key Laboratory of Polymer Processing Engineering, Ministry of Education, South China University of Technology, Guangzhou, Guangdong, 510640, China.
| | - Cong Fang
- Key Laboratory of Polymer Processing Engineering, Ministry of Education, South China University of Technology, Guangzhou, Guangdong, 510640, China.
| | - Ting Wu
- Key Laboratory of Polymer Processing Engineering, Ministry of Education, South China University of Technology, Guangzhou, Guangdong, 510640, China.
| |
Collapse
|
27
|
Hilpert M, Ilievski V, Hsu SY, Rule AM, Olmedo P, Drazer G. E-cigarette aerosol collection using converging and straight tubing Sections: Physical mechanisms. J Colloid Interface Sci 2021; 584:804-815. [PMID: 33268068 PMCID: PMC7736306 DOI: 10.1016/j.jcis.2020.10.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 10/01/2020] [Accepted: 10/03/2020] [Indexed: 12/30/2022]
Abstract
HYPOTHESIS Identification and quantification of harmful chemicals in e-cigarette aerosol requires collecting the aerosolized e-liquid for chemical analysis. In 2016, Olmedo at al. empirically developed a simple method for aerosol collection by directing the aerosol through a sequence of alternating straight and converging tubing sections, which drain the recovered e-liquid into a collection vial. The tubing system geometry and flow conditions promote inertial impaction of aerosolized e-liquid on tube walls, where it deposits and flows into the collection vial. EXPERIMENTS We use high-speed optical imaging to visualize aerosol transport in proxies of the collection system. We also determined collection efficiencies of various configurations of the collection system. FINDINGS A turbulent jet emerges from converging conical sections and impinges onto the wall of downstream tubing sections, resulting in inertial impaction and deposition of the aerosol. For inertial impaction to occur the tip radius of the converging section must be small enough for a jet to be formed and the sequence of tubing sections must be curved in a polygon-like manner such that the jet emerging from a converging section impinges on the downstream tube wall. The collection efficiency is significantly smaller without such curvature.
Collapse
Affiliation(s)
- Markus Hilpert
- Department of Environmental Health Sciences, Columbia University, United States.
| | - Vesna Ilievski
- Department of Environmental Health Sciences, Columbia University, United States
| | - Shao-Yiu Hsu
- Department of Bioenvironmental Systems Engineering, National Taiwan University, Taiwan
| | - Ana M Rule
- Department of Environmental Health and Engineering, Johns Hopkins University, United States
| | - Pablo Olmedo
- Department of Legal Medicine and Toxicology, University of Granada, Spain
| | - German Drazer
- Department of Mechanical and Aerospace Engineering, Rutgers, The State University of New Jersey, United States
| |
Collapse
|
28
|
Esmaeili AR, Mir N, Mohammadi R. Further Step toward a Comprehensive Understanding of the Effect of Surfactant Additions on Altering the Impact Dynamics of Water Droplets. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:841-851. [PMID: 33397113 DOI: 10.1021/acs.langmuir.0c03192] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The addition of surfactants to pure water for specific applications has made controlling the impact dynamics of surfactant-laden droplets a complex phenomenon. This work investigates the influence of the molecular weight (MW), concentration, and ionic nature of the surfactants as well as the substrate surface characteristics on the impact dynamics of surfactant-laden droplets using a high-speed camera at 10 000 frames per second. Sodium dodecyl sulfate, hexadecyltrimethylammonium bromide, and n-decanoyl-n-methylglucamine were used as anionic, cationic, and nonionic surfactants, respectively. We used hydrophilic glass slides, hydrophobic polytetrafluoroethylene, and superhydrophobic alkyl ketene dimer (AKD) as substrates. The results show that the efficiency of the surfactant addition in increasing the maximum spreading diameter is significantly influenced by the molecular weight and ionic nature of the solutions as well as the nonwettability of the substrate. Among all of the surfaces examined, the concentration and ionic nature of the solutions were found to be more dominant parameters in determining the energy dissipation in the retraction phase of the droplet impact on the superhydrophobic AKD surfaces. As the concentration decreases or positive charges are present in the solution, it is more likely to observe a similar retraction dynamic to pure water when the droplet hits the superhydrophobic AKD having negatively charged surface sites. Finally, in terms of the impact outcomes of the surfactant-laden droplets on the superhydrophobic AKD, it is shown that the influence of the surfactant addition is more noticeable at lower Weber numbers, where the droplet tries to rebound by overcoming the energy loss that occurred in the spreading.
Collapse
Affiliation(s)
- Amir R Esmaeili
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Noshin Mir
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Reza Mohammadi
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| |
Collapse
|
29
|
Wang Y, Zhang K, Zhao J, Wang Y, Wang S. Post-impact dynamics of droplet on bare stranded overhead power transmission lines with varying surface properties. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2020.125690] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
30
|
Yun S. Enhancing the Asymmetry of Bouncing Ellipsoidal Drops on Curved Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:14864-14871. [PMID: 33232159 DOI: 10.1021/acs.langmuir.0c02898] [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
Reducing the residence time of drops on solids has been attracting much attention in a wide range of industrial methods, such as self-cleaning and anti-icing. Classical drop dynamics is generally confined to circular symmetry and a theoretical limit of the bouncing time. In this study, we investigate the bouncing dynamics of ellipsoidal drops on cylindrical surfaces. Experimental and numerical results show that, compared with spherical ones, ellipsoidal shapes create the synergy effect of a preferential flow along the curved side, thereby leading to a significant reduction in the residence time when the drop's major axis coincides with the cylinder's axial direction. The effects of the drop ellipticity and surface curvature on the bouncing dynamics are investigated for several Weber numbers and discussed through momentum analyses. The proposed concave/convex decorated models demonstrate the feasibility of the further reduced residence time by enhancing the asymmetry in the mass and momentum distributions. This study can provide a new perspective to shape-dependent impact dynamics by emphasizing the importance of the geometric configuration between ellipsoidal drops and anisotropic surfaces in determining the extent to which the dynamics are asymmetric.
Collapse
Affiliation(s)
- Sungchan Yun
- Department of Mechanical Engineering, Korea National University of Transportation, Chungju 27469, Republic of Korea
| |
Collapse
|
31
|
Khanzadeh Borjak S, Rafee R, Valipour MS. Experimental Investigation of Water Droplet Impact on the Electrospun Superhydrophobic Cylindrical Glass: Contact Time, Maximum Spreading Factor, and Splash Threshold. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:13498-13508. [PMID: 33146013 DOI: 10.1021/acs.langmuir.0c02228] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The impinging of water droplets on superhydrophobic cylindrical glasses has been investigated experimentally by using a high-speed camera. The superhydrophobic cylindrical surfaces were fabricated by electrospinning technique combined with silane treatment. The effects of the diameter ratio of cylindrical glass and Weber number on the postimpact regime, contact time, maximum spreading factor, and splash threshold were investigated in the ranges 3.5-16 and 27-161, respectively. The results were compared with impact droplets on superhydrophobic flat glass and uncovered hydrophilic cylindrical glass. Three types of regimes were observed on hydrophilic and superhydrophobic cylindrical glasses including coating, splash, and splash-rebound. Results showed that contact time on the cylindrical surface is up to 50% less than the flat one. Moreover, the splash regime was started at the critical Weber number = 134 on high-diameter-ratio superhydrophobic cylindrical and flat surfaces while happening earlier when the diameter ratio is below D* < 4.
Collapse
Affiliation(s)
| | - Roohollah Rafee
- Faculty of Mechanical Engineering, Semnan University, Semnan 35131-19111, Iran
| | | |
Collapse
|
32
|
Esmaeili AR, Mir N, Mohammadi R. A facile, fast, and low-cost method for fabrication of micro/nano-textured superhydrophobic surfaces. J Colloid Interface Sci 2020; 573:317-327. [PMID: 32289627 DOI: 10.1016/j.jcis.2020.04.027] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 04/05/2020] [Accepted: 04/06/2020] [Indexed: 01/19/2023]
Abstract
HYPOTHESIS Alkyl ketene dimer (AKD) is frequently used in paper industry as an inexpensive sizing agent. The formation of a porous structure after curing the solidified AKD for an extra-long time (4-6 days) results in superhydrophobicity. In this study, a facile and low-cost method was utilized to turn the surface of AKD superhydrophobic in a very short period of time. EXPERIMENTS We fabricated superhydrophobic coatings by dipping glass and paper substrates in molten AKD and then treating them with ethanol after solidification. The samples were characterized by X-ray diffraction, Scanning electron microscopy, Fourier transform-infrared spectroscopy, X-ray photoelectron spectroscopy, Confocal laser scanning microscopy, and dynamic contact angle goniometry. FINDINGS The results show that briefly treating the coatings, obtained from isothermally heated AKD melt at 40 °C for 3 min, with ethanol leads to superhydrophobicity with advancing and receding contact angles of 158.7 ± 1.4° and 156.8 ± 0.9°, respectively. By increasing the melt temperature to 70 °C and its heating time to 6 h followed by ethanol treatment, the advancing and receding contact angles increased to 163.7 ± 1.3° and 162.6 ± 1.2°, respectively. This enhancement in superhydrophobicity is due to the formation of porous, entangled irregular micro/nano textures that create air cushions on the surface resulting in droplet state transition from Wenzel to Cassie.
Collapse
Affiliation(s)
- Amir R Esmaeili
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Noshin Mir
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Reza Mohammadi
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA.
| |
Collapse
|
33
|
Han J, Kim W, Bae C, Lee D, Shin S, Nam Y, Lee C. Contact time on curved superhydrophobic surfaces. Phys Rev E 2020; 101:043108. [PMID: 32422796 DOI: 10.1103/physreve.101.043108] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 03/25/2020] [Indexed: 06/11/2023]
Abstract
When a water drop impinges on a flat superhydrophobic surface, it bounces off the surface after a certain dwelling time, which is determined by the Rayleigh inertial-capillary timescale. Recent works have demonstrated that this dwelling time (i.e., contact time) is modified on curved superhydrophobic surfaces, as the drop asymmetrically spreads over the surface. However, the contact time on the curved surfaces still remains poorly understood, while no successful physical model for the contact time has been proposed. Here, we propose that the asymmetric spreading on the curved surface is driven by either the Coanda effect or inertia depending on the ratio of the drop diameter to the curvature diameter. Then, based on scaling analysis, we develop the contact time model that successfully predicts the contact time measured under a wide range of experiment conditions such as different impact velocities and curvature diameters. We believe that our results illuminate the underlying mechanism for the asymmetric spreading over the curved surface, while the proposed contact time model can be utilized for the design of superhydrophobic surfaces for various thermal applications, where the thermal exchange between the surface and the water drop occurs via a direct physical contact.
Collapse
Affiliation(s)
- Jeonghoon Han
- Department of Mechanical Engineering, Kyung Hee University, Yongin 17104, Republic of Korea
| | - Wonjung Kim
- Department of Mechanical Engineering, Sogang University, Seoul 04107, Republic of Korea
| | - Changwoo Bae
- Department of Mechanical Engineering, Kyung Hee University, Yongin 17104, Republic of Korea
| | - Dongwook Lee
- Department of Mechanical and System Design Engineering, Hongik University, Seoul 04066, Republic of Korea
| | - Seungwon Shin
- Department of Mechanical and System Design Engineering, Hongik University, Seoul 04066, Republic of Korea
| | - Youngsuk Nam
- Department of Mechanical Engineering, Kyung Hee University, Yongin 17104, Republic of Korea
| | - Choongyeop Lee
- Department of Mechanical Engineering, Kyung Hee University, Yongin 17104, Republic of Korea
| |
Collapse
|
34
|
Yun S, Kim I. Spreading Dynamics and the Residence Time of Ellipsoidal Drops on a Solid Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:13062-13069. [PMID: 31525890 DOI: 10.1021/acs.langmuir.9b01855] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Controlling bouncing drops on solid surfaces has gained significant attention because of the benefit of low residence time in anti-icing and self-cleaning strategies. Given that the drop shape at the moment of impact is classically assumed to be spherical, the residence time on a flat surface is bounded by a theoretical Rayleigh limit. In this study, we investigated the impact dynamics of oblate and prolate ellipsoidal drops to demonstrate the concept of modifying the residence time by shaping like raindrops. Experimental and numerical studies show that the initial shape plays a vital role in an increase or reduction in bounce speed of the drop, which is explained by scaling the maximum spreading time. The hydrodynamic features of ellipsoidal drops are analyzed by quantifying the temporal variations in diameters, heights, velocity fields, momenta, and energy dissipation. We believe that the ellipsoidal drop impact can provide an efficient pathway for controlling the residence time in practical applications.
Collapse
Affiliation(s)
- Sungchan Yun
- Department of Mechanical Engineering , Korea National University of Transportation , 50 Daehak-ro , Chungju 27469 , Republic of Korea
| | - Inhyeon Kim
- MEMC Korea (A GlobalWafers Company) , 854 Manghyang-ro , Seobuk-gu, Cheonan 31043 , Republic of Korea
| |
Collapse
|
35
|
Abolghasemibizaki M, Dilmaghani N, Mohammadi R, Castano CE. Viscous Droplet Impact on Nonwettable Textured Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:10752-10761. [PMID: 31339727 DOI: 10.1021/acs.langmuir.9b01109] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Viscous droplet impact on nonwettable surfaces with complex geometry is of technological importance, but the fundamental understanding of the dynamics is not entirely understood yet. In this work, liquid drops with various viscosities and impact velocities were investigated, and their behavior was correlated with contact time upon impinging nonwettable flat and textured surfaces. It was shown that in the inertial-capillary regime, the contact time between the droplet and a flat surface is independent of impact velocity, whereas for the viscous-capillary regime, it increases with impact velocity. Drops impacting on nonwettable surfaces with single and multiple macroscopic ridges generally leave the surface at a reduced contact time, compared to flat surfaces. The incorporation of a single macrotexture results in a steplike reduction in the contact time because the impacting drop reaches the maximum spreading diameter, a condition that must happen when the capillary number is below unity.
Collapse
Affiliation(s)
- Mehran Abolghasemibizaki
- Department of Mechanical and Nuclear Engineering , Virginia Commonwealth University , Richmond , Virginia 23284 , United States
- Department of Mechanical Engineering , Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Neda Dilmaghani
- Department of Mechanical and Nuclear Engineering , Virginia Commonwealth University , Richmond , Virginia 23284 , United States
| | - Reza Mohammadi
- Department of Mechanical and Nuclear Engineering , Virginia Commonwealth University , Richmond , Virginia 23284 , United States
| | - Carlos E Castano
- Department of Mechanical and Nuclear Engineering , Virginia Commonwealth University , Richmond , Virginia 23284 , United States
| |
Collapse
|
36
|
Song M, Hu D, Zheng X, Wang L, Yu Z, An W, Na R, Li C, Li N, Lu Z, Dong Z, Wang Y, Jiang L. Enhancing Droplet Deposition on Wired and Curved Superhydrophobic Leaves. ACS NANO 2019; 13:7966-7974. [PMID: 31268304 DOI: 10.1021/acsnano.9b02457] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Droplet deposition on superhydrophobic surfaces has been a great challenge owing to the shortness of the impact contact time. Despite recent research progress regarding flat superhydrophobic surfaces, improving deposition on ubiquitous wired and curved superhydrophobic leaves remains challenging as their surface structures promote asymmetric impacts, thereby shortening the contact times and increasing the likelihood of droplet splitting. Here, we propose a strategy to solve the deposition problems based on an analysis of the impact dynamics and a rational selection of additives. Combining the prominent extension property of flexible polymers with surface tension reduction of the surfactant, the well-chosen binary additives cooperatively solve retention and coverage problems by limiting the fragment and enhancing local pinning and wetting processes at a very low usage. This work advances the understanding of droplet deposition by rationally selecting additives based on the impact dynamics, which is believed to be useful in a variety of spraying, coating, and printing applications.
Collapse
Affiliation(s)
- Meirong Song
- College of Science , Henan Agricultural University , Zhengzhou , Henan 450002 , P.R. China
| | - Duan Hu
- College of Science , Henan Agricultural University , Zhengzhou , Henan 450002 , P.R. China
| | - Xianfu Zheng
- College of Science , Henan Agricultural University , Zhengzhou , Henan 450002 , P.R. China
| | - Lixia Wang
- College of Science , Henan Agricultural University , Zhengzhou , Henan 450002 , P.R. China
| | - Zhilun Yu
- College of Science , Henan Agricultural University , Zhengzhou , Henan 450002 , P.R. China
| | - Wankai An
- College of Science , Henan Agricultural University , Zhengzhou , Henan 450002 , P.R. China
| | - Risong Na
- College of Science , Henan Agricultural University , Zhengzhou , Henan 450002 , P.R. China
| | - Chuxin Li
- CAS Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences Future Technology College , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Beijing 100190 , P.R. China
| | - Ning Li
- CAS Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences Future Technology College , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Beijing 100190 , P.R. China
| | - Zhouhui Lu
- College of Science , Henan Agricultural University , Zhengzhou , Henan 450002 , P.R. China
| | - Zhichao Dong
- CAS Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences Future Technology College , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Beijing 100190 , P.R. China
| | - Yilin Wang
- Key Laboratory of Colloid and Interface Science, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , P.R. China
| | - Lei Jiang
- CAS Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences Future Technology College , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Beijing 100190 , P.R. China
- School of Chemistry , Beihang University , Beijing 100191 , P.R. China
| |
Collapse
|
37
|
Sun J, Liu Q, Liang Y, Lin Z, Liu C. Three-dimensional VOF simulation of droplet impacting on a superhydrophobic surface. Biodes Manuf 2019. [DOI: 10.1007/s42242-019-00035-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
38
|
Sayyari MJ, Fallah Kharmiani S, Abolfazli Esfahani J. A lattice Boltzmann study on dripping process during 2D droplet impact onto a wetted rotating cylinder. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2018.11.087] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
39
|
Davoudi M, Amrei M, Tafreshi H, Chase G. Measurement of inflection angle and correlation of shape factor of barrel-shaped droplets on horizontal fibers. Sep Purif Technol 2018. [DOI: 10.1016/j.seppur.2018.04.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|