Discovery
News:
Opals get their
color from the diffraction of light hitting their internal
structures, not from any inherent pigmentation. The stones form
when spheres of
silica
coalesce into compact layers as water evaporates, and the
resulting structures can produce a wide range of colors. An
international collaboration has created an elastic polymer that
duplicates that structure using nanoparticles wrapped in
rubbery shells. The shells bond the nanoparticles together and
produce a sheet that reflects different wavelengths of light as
it is stretched and the distance between the particles changes.
The colors produced also depend on the size of the
nanoparticles used. The material presents possible application
as a mechanical strain detector or as a nontoxic and colorfast
replacement for dyes. It could also be a cheaper replacement
for anticounterfeiting holograms in money.
