Article
Thermodynamics
Xin Wang, Bo Xu, Zhenqian Chen
Summary: A new hierarchical superhydrophobic surface with micropores and nanoblades (MN SHS) is proposed to enhance the jumping ability of droplets and maintain high-efficiency droplet jumping condensation at larger subcoolings. The results show that MN SHS has a higher jumping frequency and a higher proportion of multidroplets merging compared to nanostructured superhydrophobic surfaces (Nano SHS). The maximum diameter of condensate droplets on MN SHS is 50% smaller than that on Nano SHS.
APPLIED THERMAL ENGINEERING
(2023)
Article
Polymer Science
Dong Hwan Kim, Hong Gu Kwon, Hong Kyoon Choi
Summary: In this study, dewetting-induced hierarchical patterns were successfully formed using two self-assembled materials: block copolymers and colloidal crystals. The periodic structures of colloidal crystals were used as templates to generate multi-scale hierarchical patterns with block copolymers. Various concentric ring patterns were observed and explained using a free energy model. Spiral-defective features were also examined and found to be promoted by Y-junction defects.
Article
Materials Science, Coatings & Films
Yue Zhang, Tao Wang, Meng Wu, Wenchao Wei
Summary: A superhydrophobic surface with good robustness and efficient water collecting performance was successfully fabricated through structuring multilevel microstructures. The surface exhibited great water repellency, chemical stability, and maintained water proofing property even after cyclical abrasion. The water harvesting efficiency was higher than those of the previously reported surfaces, making it a potentially crucial solution for water collection in fog/mist environments.
SURFACE & COATINGS TECHNOLOGY
(2021)
Article
Chemistry, Physical
Junseong Ahn, Zhi-Jun Zhao, Jungrak Choi, Yongrok Jeong, Soonhyoung Hwang, Jiwoo Ko, Jimin Gu, Sohee Jeon, Jaeho Park, Mingu Kang, Dionisio V. Del Orbe, Incheol Cho, Hyeokjung Kang, Moonjeong Bok, Jun-Ho Jeong, Inkyu Park
Summary: A novel morphology-controllable wrinkled micro/nano hierarchical structure was developed by integrating micropatterns, nanopatterns, and wrinkles, providing unlimited design diversity and improving device performance. The structure was used as a superhydrophobic triboelectric nanogenerator with superior hydrophobicity and enhanced triboelectric effect.
Review
Chemistry, Applied
Miguel Martinez-Calderon, Thomas A. Haase, Nina Novikova, Frederick Steven Wells, Jeffery Low, Geoff R. Willmott, Neil G. R. Broderick, Claude Aguergaray
Summary: This study demonstrates the fabrication of superhydrophobic hierarchical micro- and nano-scale structures on painted surfaces using laser micro- and nanomachining. The complex chemical composition of paints plays a crucial role in determining the wettability and self-cleaning properties of the surfaces following laser ablation. This technique shows promise for industrial applications on exposed painted surfaces.
PROGRESS IN ORGANIC COATINGS
(2022)
Article
Chemistry, Physical
Xin Sui, Yubo Wang, Yongyang Sun, Wenyan Liang, Yiqing Xue, Alex Osei Bonsu
Summary: A hierarchical nanostructured model for superhydrophobicity was established to describe solid surface properties, with a focus on thermodynamic analysis of wetting states. Simulation results demonstrated a close relationship between wetting state transitions and changes in nano-cylinder height and base spacing.
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
(2021)
Review
Chemistry, Multidisciplinary
Zhifeng Hu, Fuqiang Chu, He Shan, Xiaomin Wu, Zhichao Dong, Ruzhu Wang
Summary: This review comprehensively summarizes the progress on phenomena, mechanisms, regulations, and applications of droplet impact on superhydrophobic surfaces. The focal points are droplet contact and rebound, and various applications are classified according to their requirements. The review also points out the remaining challenges and outlines future research directions.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Physical
A. K. Verma, R. K. Soni
Summary: This study presents the identification of ultra-trace analyte concentrations using laser-textured palladium-gold hierarchical superhydrophobic micro-arrays as surface-enhanced Raman sensors. The optimized fabrication parameters result in hybrid SMA-SERS sensors with excellent superhydrophobicity and uniform signal detectability down to -34.2 fM MB molecules. These sensors enable the detection and identification of multiple analytes.
SURFACES AND INTERFACES
(2023)
Article
Mechanics
Zhongyuan Ni, Fuqiang Chu, Shaokang Li, Jia Luo, Dongsheng Wen
Summary: This study investigates metastable liquid film dewetting on superhydrophobic surfaces induced by dry hole growth through a combination of experimental and theoretical analysis. It is found that the growth behavior of dry holes can lead to liquid film dewetting. Theoretical analysis reveals that the behavior of the holes is influenced by the competition between capillary force and hydrostatic pressure, and the scale of the dewetting area is affected by the Young-Laplace equation and the shape of the superhydrophobic surface.
Article
Engineering, Manufacturing
Haoxuan Sun, Fan Yang, Shuangjun Chen, Jun Zhang
Summary: In this study, a mechanically robust material with excellent superhydrophobicity was fabricated for self-cleaning and passive cooling. The material exhibited superior cooling performance and durability, making it suitable for outdoor cooling applications.
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
(2023)
Article
Engineering, Environmental
Qiong Tian, Fengxian Qiu, Xuejie Yue, Zhangdi Li, Bencheng Zhao, Tao Zhang
Summary: A sustainable and simple strategy was developed to regulate the surface structure of wastewater flocculated sludge (WFS) for the fabrication of superhydrophobic ceramic coating, maintaining excellent performance stability. This method not only contributes to the management and resource utilization of WFS, but also has potential applications in separation, catalysis, and construction.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2021)
Article
Engineering, Environmental
Umair Baig, M. A. Gondal, M. A. Dastageer
Summary: In this study, oil-water separating membranes with contrasting wetting characteristics were fabricated by dip coating trichloro(octadecyl)silane on micro porous stainless steel mesh. These membranes achieved 99% separation efficiency in a gravity driven system and maintained their wetting characteristics and efficiency even after multiple passes of oily water. The surface morphology, elemental composition, and wettability of the coated membrane were also characterized.
JOURNAL OF WATER PROCESS ENGINEERING
(2022)
Article
Chemistry, Physical
Xinwen Zhang, Tong Zhou, Jie Liu, Ruoyun Wang, Wenbin Hu, Lei Liu
Summary: A facile one-step method was proposed to fabricate superhydrophobic surfaces with controllable roughness through secondary anodic oxidation (SAO) process, resulting in volcano-like hierarchical microstructures on anodic aluminum oxide (AAO).
APPLIED SURFACE SCIENCE
(2021)
Article
Nanoscience & Nanotechnology
Zeyu Zheng, Yu Miao, Jiyuan Yao, Jiamei Chen, Jialin Wen, Xiaodan Chen, Yanxin Lu, Xiaofang Jiang, Lingling Shui
Summary: Hierarchical and periodic nanostructures of dielectrics or metals are fabricated using a facile and effective method. The programmable plasmonic-photonic structures demonstrate the synergistic effect of photonic and surface plasma resonance effects. This approach provides a promising path to construct pixelated plasmonic-photonic arrays for optical multiplexing technology.
Article
Chemistry, Multidisciplinary
Shanqiu Liu, Kangwei Chen, Alma Salim, Jingguo Li, Davide Bottone, Stefan Seeger
Summary: Through a solvent-free strategy, waterproof paper with excellent printability and mechanical strength can be fabricated by in situ surface engineering with polysilsesquioxane nanorods.
Article
Nanoscience & Nanotechnology
Donghyun Seo, Jaehwan Shim, Byungyun Moon, Kyungjun Lee, Jooyoung Lee, Choongyeop Lee, Youngsuk Nam
ACS APPLIED MATERIALS & INTERFACES
(2020)
Article
Chemistry, Multidisciplinary
Young Su Ko, Hyeon Jeong Kim, Chi Wook Ha, Choongyeop Lee
Article
Mechanics
Muchen Xu, Ning Yu, John Kim, Chang-Jin ''CJ'' Kim
Summary: This study demonstrates that under controlled flow conditions, the reduction in skin-friction drag can be achieved by using specific microtrench SHPo surfaces. The width of the trenches non-dimensionalized to the viscous length scale is found to govern the extent of skin-friction drag reduction.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Chemistry, Multidisciplinary
Ning Yu, Sarina Kiani, Muchen Xu, Chang-Jin CJ Kim
Summary: This article presents a visualization technique for the intermediate state of superhydrophobic surfaces, supported by experiments using confocal microscopy and CCD cameras, and demonstrates how to detect the state of trench surfaces through simple observation.
Review
Engineering, Mechanical
Hyungmin Park, Chang-Hwan Choi, Chang-Jin Kim
Summary: Research has shown a relatively clear understanding of the drag reduction mechanism and factors affecting superhydrophobic surfaces in turbulent flows, but challenges remain in their application in natural environments.
EXPERIMENTS IN FLUIDS
(2021)
Article
Thermodynamics
Young Su Ko, Jeonghwan Kim, Seunggeol Ryu, Jeonghoon Han, Youngsuk Nam, Choongyeop Lee
Summary: In this study, the influence of pancake-like early bouncing on the change of surface temperature during drop impact was experimentally investigated using metallic superhydrophobic surfaces. The results showed that reducing contact time can reduce heat transfer, but the inevitable increase in contact area caused by early bouncing counterbalances the effect of contact time reduction.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2022)
Article
Mechanics
Hyungyu Sung, Hongseok Choi, Chiwook Ha, Choongyeop Lee, Hyungmin Park
Summary: The combination of bubble injection and superhydrophobic surfaces provides a solution to the challenges of air flow and depletion on the surface. By introducing bubbles over superhydrophobic surfaces with longitudinal grooves, the plastron can be replenished with a small amount of air even after the surface is fully wetted. The effective plastron thickness is related to surface light intensity, which serves as a criterion for successful replenishment.
Article
Mechanics
Ikroh Yoon, Chiwook Ha, Choongyeop Lee, Seungwon Shin
Summary: This study experimentally and numerically investigates the rebounding behavior of a droplet on a spherical particle and the impact of surface curvature. The findings suggest that rebounding can be promoted on smaller particles. The physical mechanism behind this promotion is the reduced energy dissipation on smaller particles during collision, which allows for larger liquid-gas interfacial deformation and promotes rebound.
Article
Chemistry, Multidisciplinary
Md Didarul Islam, Himendra Perera, Benjamin Black, Matthew Phillips, Muh-Jang Chen, Greyson Hodges, Allyce Jackman, Yuxuan Liu, Chang-Jin Kim, Mohammed Zikry, Saad Khan, Yong Zhu, Mark Pankow, Jong Eun Ryu
Summary: This study demonstrates a simple and scalable manufacturing technique to fabricate periodic microstructures by controlling ribbing defects in the coating process. The periodic microstructures exhibit hydrophobicity and can be utilized to improve boat speed as well as enhance mechanical and electrical properties.
ADVANCED MATERIALS INTERFACES
(2022)
Article
Engineering, Chemical
Jeonghoon Han, Young-Su Ko, Youngsuk Nam, Choongyeop Lee
Summary: Recently, the thermal condition within the membrane has been explored as a means to enhance power generation in membrane-based energy harvesting from salinity difference. In this work, we experimentally demonstrate that even a negligibly small thermal gradient within a nanoporous membrane can significantly enhance osmotic power generation. Moreover, we propose that the direction of the imposed temperature difference can lead to up to 5.3 times power enhancement by influencing the effective ion concentration across the membrane.
JOURNAL OF MEMBRANE SCIENCE
(2023)
Article
Mechanics
Ning Yu, Zhaohui Ray Li, Alexander McClelland, Francisco Jose del Campo Melchor, Sun Youb Lee, Jae Hwa Lee, Chang-Jin C. J. Kim
Summary: This paper investigates the sustainability of plastrons on superhydrophobic surfaces and their impact on hydrodynamic friction drag reduction in high-speed flows. The study combines existing theories and revises the shear-driven drainage model to account for air diffusion on the superhydrophobic surfaces. Experimental results are in agreement with theoretical estimations, supporting the design of superhydrophobic surfaces for field applications.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Mi Song Nam, Ha Truong Sang, Hyoung Gwon Choi, Ki Woon Kim, Choongyeop Lee, Yun Jung Heo
Summary: Precise and controlled drug delivery is crucial in continuous infusion systems. This study presents a novel approach to passively control a flow rate even under fluctuating pressure by utilizing a flow regulator consisting of microchannels and a flexible membrane. The concept successfully maintains a steady output flow rate within a target pressure range, offering a promising solution for achieving stable drug delivery.
Article
Physics, Fluids & Plasmas
Christophe Pirat, Cecile Cottin-Bizonne, Choongyeop Lee, Stella M. M. Ramos, Olivier Pierre-Louis
Summary: This study reports a well-controlled experiment of drop breakup, where bubble growth is triggered by a decrease in ambient pressure. The researchers found a transition from top-breakup to triple-line breakup depending on the initial contact angle of the drop. A minimal model based on inertial dynamics and constant bubble pressure is proposed, which accurately captures the growth of the bubble and the distinction between top or triple-line breakup.
PHYSICAL REVIEW FLUIDS
(2023)
Article
Chemistry, Physical
Changwoo Bae, Seungtae Oh, Jeonghoon Han, Youngsuk Nam, Choongyeop Lee
Article
Physics, Fluids & Plasmas
Jeonghoon Han, Wonjung Kim, Changwoo Bae, Dongwook Lee, Seungwon Shin, Youngsuk Nam, Choongyeop Lee