Superhydrophobic

SuperHydrophobic means Super Water Repellent. A superhydrophobic surface sheds water like drops on a lotus leaf.

Hydrophilic vs. hydrophobic. The meaning of contact angle

Hydrophilicity, comes from the Greek ύδωρ, (water) and φιλία (friendship). It refers to a physical property of a material that can transiently bond with water (H2O) through hydrogen bonding.

A hydrophilic material is a friend of water. Friends like to come closer, so a water droplet would spread on a hydrophilic surface. Furthermore water can enter the pores of a hydrophilic material and totally wet it. Most natural materials are hydrophilic.

The evaluation of hydrophilicity is made through water contact angle measurements. A water droplet would occupy as long surface of the hydrophilic material as possible. So the water contact angle will be significantly low.

Hydrophilic material

Hydrophobicity comes also from the Greek ύδωρ, (water) and φόβος (fear). It refers to the physical property of a material (known as a hydrophobic) that repels a mass of water.

Water would be afraid of a hydrophobic material. So a water droplet would try not to touch large area of the surface and the shape of the droplet would be spherical. Hydrophobic natural materials are waxes, oils and fats.

The evaluation of hydrophobicity is made through water contact angle measurements. A water droplet would be spherical so the water contact angle will be significantly high.

Hydrophobic material

Comments(26)

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James Trato

April 03, 2009 at 2:02 pm

Your site has good and revelant information on hydrophobic surfaces. Have been in this field since the middle 80′s with ENVICOAT.

J. Trato


SuperHydroPhobicCoating.com

April 04, 2009 at 9:18 am

Thank you, Mr. Trato!
We are happy that you like our articles on the issue and we hope that you will find the time to subscribe to our news feed and participate in the discussions.


kishor

May 02, 2009 at 8:43 am

I am working on chemical synthesis of ZnO nanomaterials. I have studied contact angle for my samples(as-deposited and annealed). The surface morphology istudy shows flakelike morphology with no any morphological changes after annealing. The contact angle decreses due to annealing probably due to increase roughness in the sample.
The contact angle decrases for increasing the surface roughness..It is in accordance with wenzals law..But for practical evidence we measure roughness on surace profiler which gives roughness in Angston unit and theorotical we use quantity “r” as roughness factor in the equation ..
The question is what is the relationship between the roughness and the roughness factor…
Plz do reply
yours sincerely


Editor

May 06, 2009 at 10:24 am

Dear friend,

thank you for your question. Unfortunately there is no way to connect the roughness r
of Wenzel’s equation with the roughness (ra or r rms) estimated rom a tip profilometer.
You must use an optical profilometer or even better an AFM to measure the roughness
on the surface of ZnO nanomaterials.
The above instruments have the appropriate software and estimate the ratio of the rough surface to the smooth surface which is the roughness r of the Wenzel’s equation.

Best regards,


L

August 26, 2009 at 10:02 pm

Question:

Fully submerged – within 0.5 meters from air/water surface.

How does this material react with water bubbles under water, will the water bubbles adhere to the surface without rupturing?


Prasant Roy

November 20, 2009 at 2:10 pm

I request to know about any floatation method about the floatation techniques of Monazite mineral floatation. It may be of direct or reverse floatation. plz let me know about the minerals reagents to be used as depressant, frother & collector etc. for the process. Ours is beach sand mineral separation plant. Here we get sillimanite in froth floatation process as froath, using sodium silicate as depressant & oleic acid as collector as well as frother. Here other minerals like ilmenite rutile, zircon & garnet are produced from beach sand by taking advantage of their physical properties like conducting & magnetic etc.
Regards.


Stephane Lacasa

November 28, 2009 at 2:14 pm

Thank you for sharing , love this article.

Looking for a super hydrophobic coating for plexiglass????


Andrey

January 11, 2010 at 3:19 pm

Could smb tell, what is the relationship between chemistry and geometry in the physics of low surface energy?


nur

January 17, 2010 at 11:42 pm

hi. i want to ask you about the relationship between contact angle and mechanical properties such as tensile strength.


Joel Ibarra

January 25, 2010 at 12:58 pm

Hello,

Im working for my senior design project in a system that eliminates condensation on wall surfaces. How would you think that this material would be a feasible solution. I’ve been searching around and found some information about a material that with the use of current can go from hydrophilic to hydrophobic, but can’t find anything about it other than that.

Great webpage its helping me a lot with my research.

Joel


ravikumar

October 12, 2010 at 8:04 am

what is the terms water contamination stick in a metal or semiconductor surface


esttel.

January 31, 2011 at 2:31 pm

ESTTEL. Helo! my concepts are clear through these deffinations.thank u so much.bye byeeeeeeeeeeeeeeeeeee.


mayank saxena

May 20, 2011 at 12:31 pm

Sir,Some information are provided for polymer membrane by pervaporation process



[...] More information: Hydrophilic vs Hydrophobic: The Meaning of Contact Angle. [...]


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Vamsee Krishnam Raju

January 19, 2012 at 3:01 am

I am working on evaluating the hydrophobic characterisitc of magnesium stearate. Could you share various methods to eveluate the same?

Thanking you with anticipation of the beedback on my request.


Sheikh Monirul Haque

February 15, 2012 at 12:45 am

Thank you sir,i learned some thing.


ahmed

February 16, 2012 at 4:14 pm

Bismillahir Rahmanir Raheem

Assalamu alaikum Sheikh Monirul Haque,

~~Help from ALLAH and success is near~~

***NASRUMINALLAH WA FATHUN QAREEB***

~~Help from ALLAH and success is near~~

pl send e-mail id, we are mfg in sun goggles,

Fee Amanillah.

Ahmed


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February 28, 2012 at 5:58 pm

[...] More information on hydrophobic/hydrophilic sciences:http://superhydrophobiccoating.com/hydrophilic-hydrophobic-8/ [...]


Mert

March 09, 2012 at 4:19 pm

I wanna ask yo a question how can you make a surface hydrophoic not changing its physical properties?


saif

March 13, 2012 at 3:42 am

thank you alot


Pakrudheen

March 20, 2012 at 10:43 am

Please tell anyone, how to measure the hydrophobicity for dendrimers or polymers?


islam

March 21, 2012 at 6:05 am

thank u


robert schoemmell

March 31, 2012 at 8:21 am

i WAS WONDERING IF THERE -S A DO=IT YOURSELF SRAY ON SUPER HYDROPHOBIC COATING//


marjun

July 06, 2012 at 4:58 am

what is the ratio of the separation of grooves, height of the grooves, with the volume of water on top of a superhydrophobic surface?


Tripurari Rao Gautam

August 22, 2012 at 1:02 am

I want to know what is contact angle of water drop on a surface below which the surface is said to be hydrophilic and above which said to be hydrophobic.