Marangoni Flow-Induced Droplet Deformation for Micromirror Applications

2009 ◽  
Author(s):  
Yen-Wen Lu ◽  
Rakesh Dhull
Keyword(s):  
Contact Angle ◽  
Contact Angle Hysteresis ◽  
Marangoni Flow ◽  
Droplet Deformation ◽  
Simple Method ◽  
Tilting Angle

A simple method that utilizes Marangoni flow to create droplet deformation and to tilt micro-objects is presented. Contact angle hysteresis is employed to prevent the droplet from rolling away from the position. The device consists of a micromirror placed on the droplet, and can produce a 6.5° tilting angle when actuated at 30 V. It also demonstrates its scanning capability and potential as a micromirror.

scholarly journals A Simple Method to Create Superhydrophobic Aluminium Surfaces

2012 ◽  
Vol 706-709 ◽  
pp. 2874-2879 ◽  
Author(s):  
R. Jafari ◽  
Masoud Farzaneh
Keyword(s):  
Contact Angle ◽  
Stearic Acid ◽  
Synergistic Effects ◽  
Low Cost ◽  
Contact Angle Hysteresis ◽  
Spray Coating ◽  
Superhydrophobic Surfaces ◽  
Water Contact ◽  
Simple Method ◽  
Static Contact

Superhydrophobic surfaces were prepared using a very simple and low-cost method by spray coating. A high static water contact angle of about 154° was obtained by deposition of stearic acid on an aluminium alloy. However, this coating demonstrated a high contact angle hysteresis (~ 30º). On the other hand, superhydrophobic surfaces with a static contact angle of about 162º and 158º, and a low contact angle hysteresis of about 3º and 5º were respectively obtained by incorporating nanoparticles of SiO2and CaCO3in stearic acid. The excellent resulting hydrophobicity is attributed to the synergistic effects of micro/nanoroughness and low surface energy. A study of the wettability of these surfaces at temperatures ranging from 20 to-10 °C showed that the superhydrophobic surface becomes rather hydrophobic at supercooled temperatures.

scholarly journals Preparation of Superhydrophobic Steel Surfaces with Chemical Stability and Corrosion

Coatings ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 398 ◽  
Author(s):  
Chongwei Du ◽  
Xiaoyan He ◽  
Feng Tian ◽  
Xiuqin Bai ◽  
Chengqing Yuan
Keyword(s):  
Contact Angle ◽  
Corrosion Resistance ◽  
Carbon Steel ◽  
Chemical Stability ◽  
Superhydrophobic Surface ◽  
Contact Angle Hysteresis ◽  
Water Contact ◽  
Simple Method ◽  
Q235 Carbon Steel ◽  
Steel Surfaces

Corrosion seriously limits the long-term application of Q235 carbon steel. Herein, a simple fabrication method was used to fabricate superhydrophobic surfaces on Q235 carbon steel for anticorrosion application. The combination of structure and the grafted low-surface-energy material contributed to the formation of superhydrophobic steel surfaces, which exhibited a water contact angle of 161.6° and a contact angle hysteresis of 0.8°. Meanwhile, the as-prepared superhydrophobic surface showed repellent toward different solutions with pH ranging from 1 to 14, presenting excellent chemical stability. Moreover, the acid corrosive liquid (HCl solution with pH of 1) maintained sphere-like shape on the as-prepared superhydrophobic surface at room temperature, indicating superior corrosion resistance. This work provides a simple method to fabricate superhydrophobic steel surfaces with chemical stability and corrosion resistance.

scholarly journals Producing superhydrophobic/oleophobic coatings on Cultural Heritage building materials

2018 ◽  
Vol 90 (3) ◽  
pp. 551-561 ◽  
Author(s):  
Maria J. Mosquera ◽  
Luis A.M. Carrascosa ◽  
Nabil Badreldin
Keyword(s):  
Contact Angle ◽  
Surface Energy ◽  
Cultural Heritage ◽  
Building Materials ◽  
Contact Angle Hysteresis ◽  
Simple Method ◽  
Cleaning Performance ◽  
Static Contact ◽  
Heritage Building ◽  
Building Surfaces

AbstractWater is the main vehicle of decay agents in Cultural Heritage building materials exposed to weathering. In this work, a simple method to produce superhydrophobic/oleophobic coatings building materials, including under outdoors conditions, has been developed. In addition, a study of the behavior of the developed coatings on different substrates (limestone, granite, concrete and wood) is reported. The addition of 40 nm-SiO2nanoparticles to a fluoroalkylsilane reduces surface energy and produces a Cassie-Baxter surface in all the materials evaluated. It promotes high static contact angle values of around 160°, and a contact angle hysteresis of around 3°, giving rise to repellence. The building surfaces also demonstrate an excellent self-cleaning performance. The coatings maintain the building materials esthetics as required in the Cultural Heritage field. Finally, the coating presents a long-lasting performance due to condensation reactions producing effective grafting to the four building materials evaluated.

scholarly journals Resistance of Superhydrophobic Surface-Functionalized TiO2 Nanotubes to Corrosion and Intense Cavitation

Nanomaterials ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 783 ◽  
Author(s):  
Weidi Hua ◽  
Piyush Kar ◽  
Partha Roy ◽  
Lintong Bu ◽  
Lian Shoute ◽  
...  
Keyword(s):  
Contact Angle ◽  
Electrochemical Impedance ◽  
Saline Water ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Water Jet ◽  
Fluoride Ions ◽  
Simple Method ◽  
Jet Impact ◽  
Harsh Conditions

The availability of robust superhydrophobic materials with the ability to withstand harsh environments are in high demand for many applications. In this study, we have presented a simple method to fabricate superhydrophobic materials from TiO2 nanotube arrays (TNTAs) and investigated the resilience of the materials when they are subjected to harsh conditions such as intense cavitation upon ultrasonication, corrosion in saline water, water-jet impact, and abrasion. The TNTAs were prepared by anodization of Ti foil in buffered aqueous electrolyte containing fluoride ions. The hydrophilic TNTAs were functionalized with octadecylphosphonic acid (ODPA) or 1H, 1H′, 2H, 2H′-perfluorodecyl phosphonic acid (PFDPA) to form a self-assembled monolayer on the TNTA surface to produce superhydrophobic ODPA@TNTA or PFDPA@TNTA surfaces. The superhydrophobic ODPA@TNTA and PFDPA@TNTA have contact angles of 156.0° ± 1.5° and 168° ± 1.5°, and contact angle hysteresis of 3.0° and 0.8°, respectively. The superhydrophobic ODPA@TNTA and PFDPA@TNTA were subjected to ultrasonication, corrosion in saline water, and water-jet impact and abrasion, and the resilience of the systems was characterized by electrochemical impedance spectroscopy (EIS), contact angle (CA) measurements, diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS), and field-emission scanning electron microscopy (FESEM). The results presented here show that superhydrophobic ODPA@TNTA and PFDPA@TNTA are robust and resilient under the harsh conditions studied in this work, and indicate the potential of these materials to be deployed in practical applications.

A NEW APPROACH TO INVESTIGATE CONTACT ANGLE HYSTERESIS

2018 ◽  
Author(s):  
Qiao Liu ◽  
Abbasali Abouei Mehrizi ◽  
Hao Wang
Keyword(s):  
Contact Angle ◽  
Contact Angle Hysteresis ◽  
New Approach

Drop impact on solids: contact-angle hysteresis filters impact energy into modal vibrations

2021 ◽  
Vol 923 ◽  
Author(s):  
Vanessa R. Kern ◽  
Joshua B. Bostwick ◽  
Paul H. Steen
Keyword(s):  
Contact Angle ◽  
Impact Energy ◽  
Contact Angle Hysteresis ◽  
Drop Impact

Abstract

scholarly journals An inversion of contact angle hysteresis when a liquid drop slides up on an inclined plane under the spark discharge action

2021 ◽  
Vol 33 (6) ◽  
pp. 061707
Author(s):  
Alexander E. Dubinov ◽  
Djamilya N. Iskhakova ◽  
Valeria A. Lyubimtseva
Keyword(s):  
Contact Angle ◽  
Liquid Drop ◽  
Contact Angle Hysteresis ◽  
Spark Discharge ◽  
Inclined Plane

scholarly journals Biomimetic Approach for the Elaboration of Highly Hydrophobic Surfaces: Study of the Links between Morphology and Wettability

Biomimetics ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 38
Author(s):  
Quentin Legrand ◽  
Stephane Benayoun ◽  
Stephane Valette
Keyword(s):  
Contact Angle ◽  
Ginkgo Biloba ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Textured Surfaces ◽  
Replication Process ◽  
Wetting Behavior ◽  
Static Contact ◽  
Biomimetic Approach ◽  
Highly Hydrophobic

This investigation of morphology-wetting links was performed using a biomimetic approach. Three natural leaves’ surfaces were studied: two bamboo varieties and Ginkgo Biloba. Multiscale surface topographies were analyzed by SEM observations, FFT, and Gaussian filtering. A PDMS replicating protocol of natural surfaces was proposed in order to study the purely morphological contribution to wetting. High static contact angles, close to 135∘, were measured on PDMS replicated surfaces. Compared to flat PDMS, the increase in static contact angle due to purely morphological contribution was around 20∘. Such an increase in contact angle was obtained despite loss of the nanometric scale during the replication process. Moreover, a significant decrease of the hysteresis contact angle was measured on PDMS replicas. The value of the contact angle hysteresis moved from 40∘ for flat PDMS to less than 10∘ for textured replicated surfaces. The wetting behavior of multiscale textured surfaces was then studied in the frame of the Wenzel and Cassie–Baxter models. Whereas the classical laws made it possible to describe the wetting behavior of the ginkgo biloba replications, a hierarchical model was developed to depict the wetting behavior of both bamboo species.

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