The iridescence of a material is due to the fact that the surface of that material generates optical interferences to the reflected light.
For example a thin layer of soapy water has iridescence (this is best seen in bubbles).
As I have read, this effect can also occur because there are different semi-transparent layers of microscopic thickness, of different refractive
indices (diffraction iridescence).
For example, a thin film of diesel over water can generate iridescent diffraction.
In basis all this, I'm trying to make a iridescent dye, treatment or varnish based on household materials.
Can someone help me?
Edit: I would like to obtain a transparent dye, treatment or varnish.
[Edited on 3-8-2017 by Onesiton]DrP - 3-8-2017 at 03:55
I do not know about household goods... but in the industry you can now get pearlescent pigments which help impart iridescence to a paints appearance.
They are ground up bits of pearlescent rocks I think.
I am guessing that it was the motor industry that first started to use metallic iridescent paints. That was the first time I saw them in use anyway.
Sorry that this won't help you make an iridescent varnish out of home materials.... maybe you could grind up some oyster shells in a mortar and
pestle or something? That might work. Onesiton - 3-8-2017 at 04:21
Better than a pearlescent dye, what I want to achieve is a transparent substance that possesses iridescence, or at least a dye that can difract to any
of the colours of the rainbow.
[Edited on 3-8-2017 by Onesiton]DrP - 3-8-2017 at 05:42
What if you had a very small amount of the pigment in a transparent coating... might work...
...Or have several coats of it, each one of slightly different RI or with a slightly different loading of the pigment... most in the first layers and
less in the top layer?
Maybe I am clutching at straws... just thinking aloud really. Melgar - 6-8-2017 at 14:25
Better than a pearlescent dye, what I want to achieve is a transparent substance that possesses iridescence, or at least a dye that can difract to any
of the colours of the rainbow.
[Edited on 3-8-2017 by Onesiton]
To do that, you need to have it be very thin then, on the order of magnitude of hundreds of nanometers, to correspond with the approximate wavelength
of visible light. Since that's very hard to achieve with traditional coating methods, in a form that will stay attached, it's usually done with
pearlescent pigments, which are usually made from a form of silica similar to what's found in opals.
