1 research outputs found
Color changes upon cooling of Lepidoptera scales containing photonic nanoarchitectures, and a method for identifying the changes
The effects produced by the condensation of water vapor from the environment in the various intricate
nanoarchitectures occurring in the wing scales of several Lepidoptera species were
investigated by controlled cooling (from 23° C, room temperature to -5 to -10° C) combined with
in situ measurements of changes in the reflectance spectra. It was determined that all photonic
nanoarchitectures giving a reflectance maximum in the visible range and having an open
nanostructure exhibited alteration of the position of the reflectance maximum associated with the
photonic nanoarchitectures. The photonic nanoarchitectures with a closed structure exhibited little
to no alteration in color. Similarly, control specimens colored by pigments did not exhibit a
color change under the same conditions. Hence, this method can be used to identify species with
open photonic nanoarchitectures in their scales. For certain species, an almost complete disappearance
of the reflectance maximum was found. All specimens recovered their original colors
following warming and drying. Cooling experiments using thin copper wires demonstrated that
color alterations could be limited to a width of a millimeter or less. Dried museum specimens did
not exhibit color changes when cooled in the absence of a heat sink due to the low heat capacity
of the wings