The secret is out! Mechanochemistry is behind Rudolph’s ability to save Christmas.
The hammer impact stretches a little plug of PDMS, which in turn transfers force to spiropyran cross-linkers and pulls them open into their purple merocyanine form. Credit to Doug Davis, Jeff Moore, Nancy Sottos, Scott White and friends at UIUC for developing spiropyran as a mechanochrome. No actual reindeer were harmed in the making of this video.
Happy Holidays from the Craig Group!