'Scratch and Sniff
' refers to the end result of Micro-Fragrance Coating technology
Invented by 3M
, this microencapsulation technology
allows the application of
, released by pressure
Present in perfume advertisements in magazines, on stickers, and even
movie paraphernalia (Polyester, a movie made in 1981 featured 'Odorama', and
invited users to smell a card at various points during the movie), scratch and sniff technology is bigger than banana-scented Donkey Kong adhesives.1
Fragrances, almost by definition, must be very volatile -- in order to
preserve them, one must prevent them from vapourizing. The most common way to do this, of
course, is to keep them in an air-tight container. This is exactly how scratch and
sniff works -- but on a much tinier scale.
Consider thousands of miniscule (of the order of a few microns in diameter)
plastic (or gelatin, or glass) spheroids containing small amounts of a
fragrance, suspended in an ink or glue and applied to a piece of paper.
Scratching or rubbing this paper will rupture many of these
capsules, releasing the scent.
It's worthwhile to note that this microencapsulation technology was originally developed
to create carbonless pressure-sensitive copy paper (aka no carbon required or NCR paper). The bottom of the top sheet is
covered with microcapsules containing a colourless ink, while the bottom
sheet is coated with a developer chemical.
The Boston Museum of Science web site (see link below) has an excellent picture of these
microcapsules, taken at 1000x magnification.
/me scratches vigourously at the corner of the desk and inhales deeply. 'Mmm...
I love lilacs.'
- The Internet Movie Database
- The Straight Dope
- Boston Museum of Science
1 Polyester's tagline
enough, 'Smelling is