How a liquid lens works (electrowetting)

A liquid lens works by changing the shape of a water drop by creating an electrostatic field that pulls on the water molecules. I show how water can be affected by a high voltage supply and an electrostatically charged comb.

The process by which the droplet changes shape is known as electrowetting.

[trp]

This is being implemented in a smartphone by Xiaomi launching on the 29th. So hyped this technology is coming to the mass market.

[AppliedScience]

I tried the experiment with a jug of distilled water. A charged piece of PVC plastic pipe deflected the water stream coming directly from the new, pure jug of distilled water. I'm pretty sure dissolved ions do not play a role. I'm really tempted to show a video with distilled vs. salt water.

[AppliedScience]

I've chosen to spend money on my tech hobbies instead of the more typical expenses like travel/vacations, expensive cars, kids, etc.

[pirobotbeta]

Teflon can be made sticky by ion stripping.
Get yer stuff in vacuum, paint it with some toasty ionized gasses which acts much like molecular sand-blasting.
Opens up sites for bonding, lets the adhesive stick!

[FilipWahlberg]

0:47 "I'm not sure how they got the adhesive to stick to the teflon itself"... When YOU say you're not sure how something is done, the answer must be pure magic...

[deefdeefdeef]

Your videos are always so well produced and topically interesting. Thanks, Ben!

[ChileMamaLC]

Great video. I teach a hands-on science pullout to gifted elementary schoolers and we've been exploring properties of water. I think I'll link to this in my newsletter so they can see real-life uses and hear someone else use all this great science vocabulary too :)

[adrienperie]

They use this principle in those new EWD's (electro wetting displays), were a black liquid is used as a curtain that you can move from the red part of the pixel to the green and the blue. They made them to be as similar to LCD's as possible, they work the same way except they don't use polarisation of light at all. Apparently they are 3 times as efficient and much more bright when used in direct sunlight.

[jeanrayleigh]

For anyone curious, the oil they use that has a density like that of water isn't vegetable oil or petroleum oil, but rather silicone oil - a polydimethylsiloxane like they put in kinetic sand.

[JonW]

In answer to your question about getting adhesive to stick to the PTFE. Assuming the tape is polythene, they could easily get an adhesive to stick to the polythene then by simply blowing F2 gas over the surface of one side of the polyethylene you get a PTFE surface on the polythene. I think that's how they put a PTFE coating on the inside of polythene pipes.

[lekoman]

See, this is what always gets me. People who claim that junk science is, even if it ends up being wrong, at very worst "harmless, " fail to recognize that it gets in the way of us knowing real things about... real things. I'm fascinated by this concept... but now if I go research it, I'm a little nervous I'm gonna end up with nothing but misinformation. I guess I shouldn't let that stop me from trying to understand -- it probably won't -- but even still: Grr.

[AppliedScience]

The material that you are describing is called electret. Paraffin can be made into electret. I am not sure about water. I did a quick search, but unfortunately, electrets are often referenced by crackpot, junk-science people so getting real information on the net can be difficult.

[JustAbitCurious]

I LOVE THIS CHANNEL!!! You are truly inspiring to me.
Greetings from Austria

[atenrok]

No. Water will not become magnetic in this case
1) there are no electrons with uncoupled spins in H2O, so water cannot be magnetic
2) because you apply electric field, not magnetic, and water does not have multiferroic properties.

However, if you apply strong enough electric field (order of MV/m) you can disrupt hydrogen-oxygen bonds and the water will have hard time freezing. (S. V. Schevkunov and A. Vegiri, Electric field induced transitions in water clusters, J. Mol. Struct. 593 (2002))

[morphtrust]

I find this particularly interesting because I am hoping to use the same properties that you show water having due to it being a positively and negatively charged molecule (both positive charge atoms and negative charge atoms in it.) and as we know from electrolysis they can be separated, so now the trick is to figure out how to control depositing the separated atoms to a surface :) (the theory behind my atom based 3D printer)

[AustinSteingrube]

Electrical engineer here - the water stream deflects because the like charges are repelled away from the the high potential object either to ground (as in the faucet) or to virtual ground (anything of large enough size to act as a sink). The remaining charges (opposite) are attracted to the high potential object causing deflection. These charges, by the way, don't need to be a chemical ion. You have free electrons in every material.

You can see the reverse of this with a single droplet. It does not have a large enough size to allow for charges to get moved far enough away. To provide this, you have to add an electrode that can pull the voltage down/up.

[ThomasAndersonbsf]

I actually had imagined a contact lens of flexible materials (soft contacts) that was hollow as a slit and there was a reservoir that had a pump hooked up to it to pump liquid into and out of that hollow slit to cause it to expand or contract, so that the contact lenses could adjust focal distance on the fly, after I thought of using something like silicon and that pump system to make a variable contact lens mold, so this is all very interesting to me. (the ideas on customizable lenses I mentioned were like from 1995 or so, back when I had my first soft contacts, :)

[JB-dmzt]

I think this would be pretty interesting in a camera or something of that nature.
Or obsolete, still though, great demonstration.

[islambouzaher]

Coming after Xiaomi announced the Mi mix

[surendersingal]

Very interesting demo Sir, of water being attracted to comb. What kind of applications are anticipated of this attractikn?