[john0eere]

hi guys! first post, if it's in the wrong forum my apologies.

i am working on creating a product and have been scouring the net and haven't had any luck finding an answer. i am looking for a cheap chemical in either powder or liquid form that can be sealed in a plastic, and when punctured, react with the environment (assuming oxygen or carbon dioxide) to change color.

the ultimate plan is to microencapsulate the substance and apply it to the outside of plastic. when the encapsulated substance is broken it is exposed to the environment and changes color. with it being microencapsulated, we also have the option of having two chemicals react with each other...my original thought is that it would be more economical to have the environment being the reacting agent (over packing in two substances).

thanks in advance!

[fledarmus]

How quickly does it need to react?

p-benzoquinones are the first to pop into my mind - the hydroquinone form is easily oxidized to the benzoquinone, and the benzoquinone easily reduced to the hydroquinone. Depending on the substituents, you have a fairly wide variety of color changes possible, as well as a fairly wide range of reactivities.

[john0eere]

How quickly does it need to react?

p-benzoquinones are the first to pop into my mind - the hydroquinone form is easily oxidized to the benzoquinone, and the benzoquinone easily reduced to the hydroquinone. Depending on the substituents, you have a fairly wide variety of color changes possible, as well as a fairly wide range of reactivities.

I am looking for a fairly immediate change in color, although it doesn't have to be immediate. sooner the better.

I am not picky on the color of the change.

I will look into what you've posted here, any other opinions would be very helpful!!