Color changeable dyes for indicating exposure, methods of making and using such dyes, and apparatuses incorporating such dyes
According to embodiments of the present application, a color changeable dye can comprise a redox indicator, a reduction reaction initiator, an electron donor, an oxygen scavenger, an indicator barrier agent, a thickening agent and an agent to facilitate mixing. The color changeable dye is a first color in the presence of oxygen, capable of changing to a second color upon reduction in a substantially oxygen free environment, and capable of changing back to the first color after exposure to oxygen for a period of time corresponding to the intended use time of a disposable or limited use product. Methods of making and using the color changeable dye and apparatuses incorporating such dye are also disclosed.
1. A color changeable dye comprising:
a redox indicator,
a reduction reaction initiator,
an electron donor,
an oxygen scavenger,
a thickening agent, and
an agent to facilitate mixing.
2. The color changeable dye of claim 1 wherein said color changeable dye is a first color in the presence of oxygen, capable of changing to a second color upon reduction in a substantially oxygen free environment, and capable of changing back to the first color after exposure to oxygen for a period of time corresponding to the intended use time of a disposable or limited use product.
3. The color changeable dye of claim 1 further comprising an indicator barrier agent.
4. The color changeable dye of claim 1 wherein the redox indicator is indigo-tetrasulfonate.
5. The color changeable dye of claim 1 wherein the reduction reaction initiator is titanium dioxide.
6. The color changeable dye of claim 1 wherein the electron donor is glycerol.
7. The color changeable dye of claim 1 wherein the oxygen scavenger is sodium bisulfate.
8. The color changeable dye of claim 1 wherein the oxygen scavenger is ascorbic acid.
9. The color changeable dye of claim 3 wherein the indicator barrier agent is poly(diallyldimethylammonium chloride).
10. The color changeable dye of claim 1 wherein the thickening agent is 2-hydroxyethyl cellulose.
11. The color changeable dye of claim 1 wherein the agent to facilitate mixing is bentonite nanoclay.
12. The color changeable dye of claim 2 wherein said first color is blue and said second color is translucent or water white.
13. The color changeable dye of claim 2 wherein said period of time is less than about 60 minutes.
14. The color changeable dye of claim 2 wherein said period of time is between about 1 and about 168 hours.