A simple method for measuring the superhydrophobic contact angle with high accuracy

2010 ◽  
Vol 81 (6) ◽  
pp. 065105 ◽  
Author(s):  
Yi-Lin Hung ◽  
Yao-Yuan Chang ◽  
Meng-Jiy Wang ◽  
Shi-Yow Lin
Keyword(s):  
Contact Angle ◽  
High Accuracy ◽  
Simple Method

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 Laser-Etched Stretchable Graphene–Polymer Composite Array for Sensitive Strain and Viscosity Sensors

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuting Jiang ◽  
Yang Wang ◽  
Heting Wu ◽  
Yuanhao Wang ◽  
Renyun Zhang ◽  
...  
Keyword(s):  
Contact Angle ◽  
Polymer Composite ◽  
Dna Microarrays ◽  
Soft Materials ◽  
Control Surface ◽  
Strain Sensing ◽  
Textured Surfaces ◽  
Simple Method ◽  
Spacing Ratio ◽  
Smart Coatings

Abstract The ability to control surface wettability and liquid spreading on textured surfaces is of interest for extensive applications. Soft materials have prominent advantages for producing the smart coatings with multiple functions for strain sensing. Here, we report a simple method to prepare flexible hydrophobic smart coatings using graphene–polymer films. Arrays of individual patterns in the films were created by laser engraving and controlled the contact angle of small drops by pinning the contact lines in a horizontal tensile range of 0–200%. By means of experiments and model, we demonstrate that the ductility of drops is relied on the height-to-spacing ratio of the individual pattern and the intrinsic contact angle. Moreover, the change of drop size was utilized to measure the applied strain and liquid viscosity, enabling a strain sensitivity as high as 1068 μm2/%. The proposed laser-etched stretchable graphene–polymer composite has potential applications in DNA microarrays, biological assays, soft robots, and so on.

Methodology for High Accuracy Contact Angle Measurement†

Langmuir ◽  
2009 ◽  
Vol 25 (24) ◽  
pp. 14146-14154 ◽  
Author(s):  
A. Kalantarian ◽  
R. David ◽  
A. W. Neumann
Keyword(s):  
Contact Angle ◽  
Contact Angle Measurement ◽  
High Accuracy ◽  
Angle Measurement

scholarly journals A Simple Method For Determining Optimum Corrections For High-Accuracy Epma In Difficult Chemical Systems

2002 ◽  
Vol 8 (S02) ◽  
pp. 438-439
Author(s):  
J. T. Armstrong ◽  
R. B. Marinenko ◽  
J. M. Davis
Keyword(s):  
High Accuracy ◽  
Simple Method ◽  
Chemical Systems

A rapid and simple method to assess the changes of human VEGF mRNA based on dual molecular beacons

2014 ◽  
Vol 6 (13) ◽  
pp. 4585-4592 ◽  
Author(s):  
Bin Liu ◽  
Wei Wang ◽  
Chen Li ◽  
Chunyi Tong ◽  
Ying Long
Keyword(s):  
High Accuracy ◽  
Fluorescence Method ◽  
Molecular Beacons ◽  
Vegf Mrna ◽  
Simple Method

A fluorescence method with wide promising applications was developed for VEGF mRNA assay with high accuracy and specificity by applying dual molecular beacons as probes.

Empirical Formulae in Correlating Droplet Shape and Contact Angle

2016 ◽  
Vol 69 (4) ◽  
pp. 431 ◽  
Author(s):  
Ten It Wong ◽  
Hao Wang ◽  
Fuke Wang ◽  
Sau Leng Sin ◽  
Cheng Gen Quan ◽  
...  
Keyword(s):  
Contact Angle ◽  
Empirical Formula ◽  
Contact Angles ◽  
Shape Deformation ◽  
Direct Identification ◽  
Simple Method ◽  
Droplet Shape ◽  
Spherical Dome ◽  
Angle Measurements ◽  
Contact Angle Measurements

In contact angle measurements, direct identification of the contact angles from images taken from a goniometer suffers from errors caused by optical scatterings. Contact angles can be more accurately identified by the height and width of the droplet. Spherical dome is a simple model used to correlate the contact angles to the droplet shape; however, it features intrinsic errors caused by gravity-induced shape deformation. This paper demonstrates a simple method of obtaining an empirical formula, determined from experiments, to correct the gravity-induced error in the spherical dome model for contact angle calculations. A series of contact angles, heights, and surface contact widths are simultaneously collected for a large amount of samples, and the contact angles are also calculated using the spherical dome model. The experimental data are compared with those obtained from the spherical dome model to acquire an empirical formula for contact angles. Compared with the spherical dome model, the empirical formula can reduce the average errors of the contact angle from –16.3 % to 0.18 %. Furthermore, the same method can be used to correct the gravity errors in the spherical dome for the volume (calculated by height and width), height (calculated by contact angle and volume), and width (calculated by contact angle and volume), and the spherical dome errors can be reduced from –20.9 %, 24.6 %, and –4.8 % to 2 %, –0.13 %, and –0.6 %, respectively. Our method is generic and applicable for all kinds of solvent and substrates, and the derived empirical formulae can be directly used for water droplets on any substrate.

SYNTHESIS AND CHARACTERIZATION OF SUPERHYDROPHOBIC ZnO HIERARCHICAL STRUCTURES

NANO ◽  
2011 ◽  
Vol 06 (03) ◽  
pp. 265-269 ◽  
Author(s):  
QUNBING ZHANG ◽  
SHIHE CAO ◽  
JUN WANG
Keyword(s):  
Contact Angle ◽  
Hydrothermal Process ◽  
Hierarchical Structures ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Zno Films ◽  
Water Contact ◽  
Simple Method ◽  
Microscopy Images

ZnO films with well-aligned hierarchical structures have been successfully synthesized at moderate temperatures using a simple catalyst-free hydrothermal process. The synthesized ZnO films are found to be single-phase, with a hexagonal wurtzite-type structure. Scanning electron microscopy images show that the well-aligned hierarchical structures are assembled with interlaced parallel sheets grown on the (400) silica surface. The water contact angle measurement indicates that the water on the films has a contact angle of about 156.3°. This clearly demonstrates that the ZnO films synthesized by this simple method have superhydrophobic properties and may be important for applications in self-cleaning surfaces, biology, and so on.

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