scholarly journals Functional Superhydrophobic Surfaces with Spatially Programmable Adhesion

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2968
Author(s):  
Duan-Yi Guo ◽  
Cheng-Huan Li ◽  
Li-Min Chang ◽  
Hung-Chang Jau ◽  
Wei-Chun Lo ◽  
...  
Keyword(s):  
Superhydrophobic Surface ◽  
Liquid Droplet ◽  
Superhydrophobic Surfaces ◽  
Patterned Surfaces ◽  
Liquid Droplets ◽  
Practical Applications ◽  
Crystal Polymer ◽  
Smart Surfaces ◽  
Enhanced Raman Scattering ◽  
Spatially Varying

A superhydrophobic surface that has controllable adhesion and is characterized by the lotus and petal effects is a powerful tool for the manipulation of liquid droplets. Such a surface has considerable potential in many domains, such as biomedicine, enhanced Raman scattering, and smart surfaces. There have been many attempts to fabricate superhydrophobic films; however, most of the fabricated films had uniform adhesion over their area. A patterned superhydrophobic surface with spatially controllable adhesion allows for increased functions in the context of droplet manipulation. In this study, we proposed a method based on liquid-crystal/polymer phase separation and local photopolymerization to realize a superhydrophobic surface with spatially varying adhesion. Materials and topographic structures were analyzed to understand their adhesion mechanisms. Two patterned surfaces with varying adhesion were fabricated from a superhydrophobic material to function as droplet guides and droplet collectors. Due to their easy fabrication and high functionality, superhydrophobic surfaces have high potential for being used in the fabrication of smart liquid-droplet-controlling surfaces for practical applications.

scholarly journals Femtosecond Laser Fabricated Elastomeric Superhydrophobic Surface with Stretching-Enhanced Water Repellency

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Huan Yang ◽  
Kaichen Xu ◽  
Changwen Xu ◽  
Dianyuan Fan ◽  
Yu Cao ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Superhydrophobic Surface ◽  
Water Repellency ◽  
Superhydrophobic Surfaces ◽  
Textured Surface ◽  
Liquid Droplets ◽  
Silicone Elastomers ◽  
Highly Stretchable ◽  
First Time ◽  
Application Prospects

Abstract Highly stretchable and robust superhydrophobic surfaces have attracted tremendous interest due to their broad application prospects. In this work, silicone elastomers were chosen to fabricate superhydrophobic surfaces with femtosecond laser texturing method, and high stretchability and tunable adhesion of the superhydrophobic surfaces were demonstrated successfully. To our best knowledge, it is the first time flexible superhydrophobic surfaces with a bearable strain up to 400% are fabricated by simple laser ablation. The test also shows that the strain brings no decline of water repellency but an enhancement to the superhydrophobic surfaces. In addition, a stretching-induced transition from “petal” state to “lotus” state of the laser-textured surface was also demonstrated by non-loss transportation of liquid droplets. Our results manifest that femtosecond laser ablating silicone elastomer could be a promising way for fabricating superhydrophobic surface with distinct merits of high stretchability, tunable adhesion, robustness, and non-fluorination, which is potentially useful for microfluidics, biomedicine, and liquid repellent skin.

Two-Pronged Jet Formation Caused by Droplet Impact on Anisotropic Superhydrophobic Surfaces

2016 ◽  
Vol 138 (7) ◽  
Author(s):  
J. T. Pearson ◽  
D. Bilodeau ◽  
D. Maynes
Keyword(s):  
Superhydrophobic Surface ◽  
Liquid Droplet ◽  
Droplet Impact ◽  
Surface Patterning ◽  
Superhydrophobic Surfaces ◽  
Ohnesorge Number ◽  
Jet Formation ◽  
Anisotropic Surface ◽  
Impact Experiments ◽  
Droplet Impacts

When a liquid droplet impacts a superhydrophobic surface with anisotropic surface patterning in the form of alternating ribs and cavities, the rebounding droplet may exhibit a unique two-pronged jet emission. Droplet impact experiments with 11 different fluids of viscosity that varied by more than three orders of magnitude were conducted, and this paper quantifies the Capillary number, Ca, and Ohnesorge number, Oh, ranges over which the two-pronged phenomenon occurs. For Oh > 0.0154, the behavior was never observed, while at lower values of Oh, the behavior occurs for an intermediate range of Ca that depends on Oh.

Numerical study for the impact of liquid droplets on solid surfaces

2007 ◽  
Vol 221 (3) ◽  
pp. 293-301 ◽  
Author(s):  
A-S Yang ◽  
M-T Yang ◽  
M-C Hong
Keyword(s):  
Indium Tin Oxide ◽  
Numerical Study ◽  
Liquid Droplet ◽  
Solid Surfaces ◽  
Stainless Steel Surface ◽  
Force Model ◽  
Liquid Droplets ◽  
Construction Technique ◽  
Practical Applications ◽  
The Impact

The impinging behaviour of liquid droplets on solid surfaces is studied using a computational approach. The analysis comprises the unsteady three-dimensional conservation equations of mass and momentum, with the surface tension effect treated by the continuous surface force model. Gas-liquid interfacial motions are simulated by the volume-of-fluid method in conjunction with the piecewise linear interface construction technique. In the computer code validation for a water droplet impacting on a polished stainless steel surface, computer-generated images of the time evolution of the droplet impingement dispersal shape are compared with magnified photographs by Pasandideh-Fard et al. The flow and transport phenomena in the impingement flowfield are further examined in detail. In order to respond to the need for its use in practical applications, the study is extended to explore the spreading progression to achieve a better understanding of the interaction of a 30 μm diameter polyethylenedioxy thiophene liquid droplet with a 50 × 50 μm indium tin oxide-coating square cavity at an impact velocity of 6 m/s.

Two-Pronged Jet Formation Caused by Droplet Impact on Anisotropic Superhydrophobic Surfaces

2013 ◽  
Author(s):  
John T. Pearson ◽  
Daniel Maynes ◽  
David Bilodeau ◽  
Brent W. Webb
Keyword(s):  
Superhydrophobic Surface ◽  
Liquid Droplet ◽  
Droplet Impact ◽  
Surface Patterning ◽  
Superhydrophobic Surfaces ◽  
Ohnesorge Number ◽  
Jet Formation ◽  
Anisotropic Surface ◽  
Impact Experiments ◽  
Droplet Impacts

When a liquid droplet impacts a superhydrophobic surface with anisotropic surface patterning in the form of alternating ribs and cavities, the rebounding droplet may exhibit a unique two-pronged jet emission. Droplet impact experiments with eleven different fluids of viscosity that varied by more than three orders of magnitude were conducted, and this paper quantifies the Capillary number, Ca, and Ohnesorge number, Oh, ranges over which the two-pronged phenomenon occurs. For Oh > 0.0154, the behavior was never observed, while at lower values of Oh, the behavior occurs for an intermediate range of Ca that depends on Oh.

Fabrication of Superhydrophobic Surface by Modulating Morphology of the Organogel

Soft Matter ◽  
2021 ◽  
Author(s):  
Jianchen Zhu ◽  
Tian ren Zhang ◽  
Yajie Liu ◽  
Daoyi Lu ◽  
Peng Zhang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Superhydrophobic Surface ◽  
Superhydrophobic Surfaces ◽  
Low Molecular Weight

A kind of low-molecular weight organic gelator (LMOG) bearing hydrazine linkage and end-capped by alkoxy-substituted phenyl, namely 1, 4-bis[(3, 4-bisoctyloxyphenyl)hydrozide]phenylene (BPH-8), was used to facilely fabricate superhydrophobic surfaces by drop-casting...

Stretchable dual cross-linked silicon elastomer with superhydrophobic surface and fast triple self-healing ability at room temperature

Soft Matter ◽  
2021 ◽  
Author(s):  
Yuxing Shan ◽  
shuai liang ◽  
Xiangkai Mao ◽  
Jie Lu ◽  
Lili Liu ◽  
...  
Keyword(s):  
Superhydrophobic Surface ◽  
Room Temperature ◽  
Superhydrophobic Surfaces ◽  
Self Healing ◽  
Wearable Electronics ◽  
Actual Application ◽  
Potential Applications

Abstract. Stretchable elastomers with superhydrophobic surfaces have potential applications in wearable electronics. However, various types of damage inevitably occur on these elastomers in actual application, resulting in deterioration of the...

Numerical Analysis of Influence of Roughness of Material Surface on High-Speed Liquid Droplet Impingement

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Hirotoshi Sasaki ◽  
Yuka Iga
Keyword(s):  
Numerical Analysis ◽  
High Speed ◽  
Erosion Rate ◽  
Liquid Droplet ◽  
Material Surface ◽  
Liquid Droplets ◽  
Fluid Machinery ◽  
Droplet Impingement ◽  
Surface Liquid ◽  
Droplet Impingement Erosion

This study explains why the deep erosion pits are formed in liquid droplet impingement erosion even though the droplets uniformly impinge on the entire material surface. Liquid droplet impingement erosion occurs in fluid machinery on which droplets impinge at high speed. In the process of erosion, the material surface becomes completely roughened by erosion pits. In addition, most material surface is not completely smooth and has some degree of initial roughness from manufacturing and processing and so on. In this study, to consider the influence of the roughness on the material surface under droplet impingement, a numerical analysis of droplets impinging on the material surface with a single wedge and a single bump was conducted with changing offsets between the droplet impingement centers and the roughness centers on each a wedge bottom and a bump top. As results, two mechanisms are predicted from the present numerical results: the erosion rate accelerates and transitions from the incubation stage to the acceleration stage once roughness occurs on the material surface; the other is that deep erosion pits are formed even in the case of liquid droplets impinging uniformly on the entire material surface.

Simulation of Impaction Between Liquid Droplet and Solid Particles Based on SPH Method

2014 ◽  
Author(s):  
Shuai Meng ◽  
Qian Wang ◽  
Rui Yang
Keyword(s):  
Surface Tension ◽  
Solid Particle ◽  
Liquid Droplet ◽  
Particle Interaction ◽  
Solid Particles ◽  
Seed Particle ◽  
Liquid Droplets ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Spray Granulation

The phenomenon of impaction between liquid droplets and solid particles is involved in many scientific problems and engineering applications, such as impaction between sprayed droplet and solid particles in limestone injection desulfurization system and the collision between a droplet of the liquid to be granulated and a seed particle in fluidized bed spray granulation process. There are a lot of factors affected this phenomenon: droplet and particle size, momentum of both liquid droplet and solid particles, materials, surface conditions of the solid particles and so on. However the experimental or numerical researches have been done mostly pay attention to Specific application or process, so the impaction phenomenon has not been through studied, for example how different factors affected the impaction process with its effect on different applications. This paper focuses on the basic issue of interaction between droplet and solid particles. Three main factors were considered: ratio of diameter between the droplet and solid particle, relative velocity and the surface tension (including the contact angle between droplet and solid particle). All the study is based on simulation using SPH (smoothed particle hydrodynamics) method, and the surface tension is simulated by particle-particle interaction.

A large-scale superhydrophobic surface-enhanced Raman scattering (SERS) platform fabricated via capillary force lithography and assembly of Ag nanocubes for ultratrace molecular sensing

2014 ◽  
Vol 16 (48) ◽  
pp. 26983-26990 ◽  
Author(s):  
Joel Ming Rui Tan ◽  
Justina Jiexin Ruan ◽  
Hiang Kwee Lee ◽  
In Yee Phang ◽  
Xing Yi Ling
Keyword(s):  
Detection Limit ◽  
High Throughput ◽  
Superhydrophobic Surface ◽  
Large Scale ◽  
Molecular Sensing ◽  
M 10 ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Capillary Force Lithography

A high-throughput fabrication of a stable and uniform superhydrophobic SERS platform is demonstrated. It is able to detect trace molecules at ultra-low detection limit of 10−17 M (10 aM) using just 4 μL of analyte solutions.

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