Patent ID: 8707766

Claim:
A device for indicating the location of an air leak in a vacuum bag assembly used to compact composite parts, comprising: a sheet of the vacuum bag, the sheet having an inner face, the bag receiving a vacuum applied on the inner face, the vacuum bag positioned over a tool; and a material incorporated into the vacuum bag such that the material is integral with the vacuum bag, the vacuum bag and material forming a single layer, the material configured to transition from a first color to a second color upon activation, and from the second color to a third color due to an oxidation-reduction reaction in areas of the material exposed to oxygen, the material comprising an oxygen permeable polymer binder, semiconductor nanoparticles dispersed in the binder, an electron donor material, and a reduction-oxidation indicator material, the material configured to transition to the third color upon air leaking into the vacuum bag assembly through the vacuum bag, through the tool, or through the vacuum bag and the tool wherein the first color is blue, the second color is colorless, and the third color is green.