Agenda :
Discussion about transparent Super-hydrophobic coatings that can last multiple durable cycles without impacting water contact angle drastically .
Many method exists but they are not FACILE or One Step Method which can be easily spray coated and air cured .If you have any such research that fits the criteria do take part in discussion .
There is no specific criteria that it must be fluorine free.
Hi Rohit Rajput, what do you want to coat and how do you specify a durable cycle?
Reagrds, Stefan
It will be spray coated and durability should for about 500 abrasion sponge wipe cycles.
Substrate is Ceramic Wares (glazed) and Glass .
The intention is water beading with contact angle more than 140 deg without losing Transparency or Durability or Sprayabilty .
I under fluorosilane has to be used but they can't provide angle above 110 in an alcoholic dispersion.
The only material I know that comes close to this is parylene. I am not sure about the contact angle. However, it is applied by vacuum deposition and not by by spraying.
I fear that you only can realize max. 3 of your 4 requirements at the same time.
Thats the problem i am facing two .
Its not worthy if it cannot be sprayed .
Its not worthy if its transparency or durable.
Hi Rohit,
Here are some articles and patents that might be useful to you:
1. https://patents.google.com/patent/US20170058131A1/en -
Transparent Durable Superhydrophobic Ceramic Coating
2. https://www.mdpi.com/2079-6412/7/1/12/htm - On the durability and wear resistance of transparent superhydrophobic coatings
3. Optically transparent and environmentally durable superhydrophobic coating based on functionalized SiO2 nanoparticles - here, they deposit the coating via spin coating procedure, but you may try by spraying method. If successful, this will advance the existing knowledge :). https://www.osti.gov/pages/servlets/purl/1185439
4. Facile Fabrication of Transparent Superhydrophobic Surfaces by Spray Deposition - Article Facile Fabrication of Transparent Superhydrophobic Surfaces ...
5. One-step spraying to fabricate nonfluorinated superhydrophobic coatings with high transparency - http://agris.fao.org/agris-search/search.do?recordID=US201600041854
As a very friendly suggestion for your future research activities, if you have any thoughts in your mind or if you are trying to figure out something, the first and most important step is to "Google it" :). I know it may sound weird, but the appropriate Google-ing of things, by inserting the most relevant keywords, always end up with some useful answers of our questions, concerns, curiosity, etc.
With wishes for successful research!
Sincerely,
Karekin
Karekin,
I have some or the other way found these articles , tested them and didn't get expected results .Google is no longer helpful . ResearchGate community can help me out now.
Kai ,
I will have a look . Thanks.
I agree with you Rohit, this reminds me about one statement "the path in science is sometimes uneven, but must lead to the required result". I still remember our first attempts to stabilize superhydrophobic carbon soot coatings by means of underlying thin film of epoxy resin. We did over 350 tests with no success and at the end i was very frustrated and disillusioned. Therefore, in my frustration, i pressed with my finger both substrates (the one with soot and the other with epoxy) towards each other just to release my anger and the miracle happened - the soot was evenly and stable transferred over the resin. What we were missing in our experiments was to realize that mechanical pressure is required in order to obtain stable composite epoxy-soot coating. Saying that, i am quite sure you will succeed at the end so good luck with your research.
Sincerely,
Karekin
Yes Karekin ,
There is one most simplest method for durable super hydrophobic coating i found but its missing all pieces :
Formulation :
- Etching Acid 0.05 to 5 parts , Hydrophobic silane 0.05 to 5 parts , Solvent 85 to 99.8 parts .
- Mix a solvent with an etching chemical for about 1 minute and then adding the hydrophobic silane and mix it for about another 3 min.
- Taking solvent in a beaker and start stirring (about 300 rpm)
- Adding etching chemical to the beaker (under moisture free) and continue to stir for about 1 minute .Adding hydrophobic silane to the beaker and continue to stir for about another 3 minute. Contact angle is 155++ for glass.
Is this viable ,simply says a silane + acid + volatile solvent ?
Hi Rohit - were you able to get that method to work? It appears to be a type of phase-separation methodology. There are random islands of etched silica and islands of hydrophobic coating from the mixture. The aqueous acid and volatile solvent with silane additive form two phases, with rapid stirring, they exist as tiny droplets of one in the other. Resulting in roughened and hydrophobically modified surface - when conditions are optimized, can give you superhydrophobicity.
James , I am not able to .Seems like I am missing a piece in above formulation .Any ideas ?
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