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sirkilgoretrout t1_iv77zvh wrote

Reply to comment by thehourglasses in Researchers designed a transparent window coating that could lower the temperature inside buildings, without expending a single watt of energy. This cooler may lead to an annual energy saving of up to 86.3 MJ/m² or 24 kWh/m² in hot climates by mossadnik

Its in the second paragraph, first sentence. Common materials in layers. Silicon dioxide, silicon nitride, aluminum oxide, titanium dioxide, all on top of standard glass, with a topper of PDMS.

I’m pretty confused, as PDMS is a flexible plastic and kind of jelly-like. It doesn’t seem like something with a PDMS top layer would even be close to durable.

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cope413 t1_iv7fmq7 wrote

Pdms has been used to coat solar panels for a while now. It increases the efficiency.

Wouldn't be ideal for windows on the first floor of a house, but on a skyscraper or multi-storey building, it would be durable enough.

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sirkilgoretrout t1_iv89p9m wrote

Interesting… is that due to reduced absorption in the near-UV range vs acrylic, polycarb, etc?

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cope413 t1_iv8aitb wrote

Yes, it has exceptional intrinsic thermal and UV stability (won't suffer degradation), and it has excellent transmittance.

It's also used as a boundary to prevent lead oxides from forming (called PDMS passivating). This is the main way that PDMS increases efficiency of solar cells.

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SignorJC t1_iv8h50d wrote

Yeah but we could also have just required those skyscrapers not be built with so much glass in the first place. Horribly inefficient but we did it for the aesthetics.

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derpymcdooda t1_iv7oq28 wrote

Part of the issue with glass coating is the carriers that get used during production. Dimethyl Tin and Hydrofluoric acid are both extremely toxic and very common carriers. At least for Vapor Deposition Coating.

Source: work in an online coated float glass facility.

A bigger question is, imo, how finicky is that stack going to be to actually apply

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sirkilgoretrout t1_iv89gxn wrote

You mean like a post-market film install on current glass?

I’m definitely familiar with HF, but what the heck is dimethyl tin??

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derpymcdooda t1_iv89whw wrote

The coating stack. In online applications it's deposited while the glass is still hot, before annealing.

Dimethyltin Dichloride. Pretty nasty stuff, really.

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YobaiYamete t1_iv7rsn3 wrote

> Its in the second paragraph, first sentence.

You expect us to do more than read the headline??? Mods, ban this heretic

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sirkilgoretrout t1_iv88oxd wrote

You obviously read the comments, and the Mod’s submission statement has it too.

But I do appreciate your 3rd grade level attention span and commitment to the reddit ways. You’re part of what makes this place special 😀

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YobaiYamete t1_iv8bspm wrote

. . . the fact that you missed such an extremely obvious joke, while managing to be insulting about it, is pretty impressive tbh

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nanoH2O t1_iv83shx wrote

You can vary the cure ratio of pdms etc to get different flexibility. You can make a pdms film that is acrylic like.

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sirkilgoretrout t1_iv89382 wrote

Mind blown. When I was doing microfluidic devices with PDMS, I always ended up with surfaces that would collect dust and lint like a little kid’s squishy toy. They’d be great on day 1, but we usually re-made samples regularly. Our lab shifted to deep SU-8 molding in part to avoid some of these surface issues.

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