Sciencemadness Discussion Board

Homemade lunaplast

zeppelin69 - 9-7-2008 at 15:01

Does anyone have any idea on how to go about doing this? My limited knowledge of it, is that it is made up of "strontium aluminates" (I am assuming this really just means strontium aluminate, SrAl2O4) suspended in rubber. The commercial stuff is probably a bit more complex, but I'm just looking for a cheap and easy way to make some glow-in-the-dark stuff to play with.

On second thought, even though strontium aluminate is brighter and last longer, would it be much easier to use zinc sulfide and copper? I have very little knowledge in this area of chemistry so any input is much appreciated.

Fleaker - 9-7-2008 at 15:30

IrC, a member here, would be your best source for making these; he makes his own. From what he explained to me, it's somewhat simple if you have the equipment. I was very, very impressed with his product.

zeppelin69 - 10-7-2008 at 10:07

Thanks for the input Fleaker :) If you don't want to post his username here, would you mind sending it to me in a PM?

For now at least I have decided to use the ZnS:Cu route. The ZnS is being made by reacting the zinc powder from the center of batteries with sulfur to make crude ZnS. Then dissolving more zinc in hydrochloric acid to make a ZnCl solution. Lastly I will add HCl to the crude ZnS and bubble the H2S gas through the ZnCl solution to precipitate a more pure ZnS.

My problem comes in where I need to add the few ppm of copper. I have no clue how to go about this. Advice?

12AX7 - 10-7-2008 at 10:31

No, "IrC" is his screen name.


zeppelin69 - 10-7-2008 at 11:33

Sorry, I assumed it was a typo for IIRC. Thanks for clarifying.

Now that I have shown my complete and utter ignorance.. :D
Is the copper in this "complex" actually elemental in a fine powdered form just mixed well with ZnS? Or is it copper ions from say CuSO4 precipitated with the ZnS from something?

12AX7 - 10-7-2008 at 18:02

Doping means it's in the crystal structure, so you need the few ppm of dopant (and less than ppm of anything else!) chemically combined. This is often accomplished through diffusion: mixing the powders (or coprecipitating them), firing, milling, firing again, etc., until the correct chemistry is reached. A solution of pure ZnSO4 or ZnCl2 with the requisite amount of Cu ion present, precipitated with a sulfide (H2S is a good candidate, except for the rather substantial poisonousness; something like NH4SH might be more suitable, as it will decompose in heating) will probably prepare a fine precipitate containing the dopant, which can then be heated to get a good crystal structure. I suppose ZnS can also be grown hydrothermally (the way God does it), so instead of annealing it (not the simplest prospect given the abundance of oxygen around), it might be put in an autoclave and cooked, or something.