Butterfly Wing–Inspired Nanotechnology - The Nanobiotechnology - page 206

different.phase,.there.is.constructive.interference.for.a.given.wavelength.and.destructive.
interference.for.the.other.wavelengths.(Coath.2007)..Constructive.interference.will.make.
light.of.a.speciic.wavelength.brighter,.while.destructive.interference.will.make.light.of.a.
speciic.wavelength.darker.(or.destroy.it.completely)..The.coloration.of.the.upper.surface.
of.the.butterly.will.appear.bright.blue.or.dull.brown.based.on.the.angle.of.incidence,.the.
angle. of. observance,. the. wavelength. of. the. light. incident. on. the. butterlies'. wings,. and.
the. distance. of. the. scale. layers. from. one. another.. Light. scattering. is. also. present. and. is.
responsible.for.making.the.color.more.uniform.across.the.wing.
Due. to. the. butterly. wing's. unique. hierarchical. architecture. and. UV. relectance,. it.
demonstrates.stress-mediated.covariance.between.nanostructural.architecture.and.UV.
butterly.coloration.(Kemp.et.al..2006)..The.butterly.wing.is.very.sensitive.in.response.
to.surrounding.materials.and.temperature.change..Butterlies.use.this.unique.property.
to.help.them.survive..The.manner.in.which. Morpho .butterlies.ly.makes.them.appear.to.
rapidly.change.color.from.a.brilliant.blue.to.a.dull.brown..This.creates.the.illusion.that.
they.are.disappearing.and.reappearing,.which.makes.it.dificult.for.them.to.be.followed.
by.predators..Further,.they.can.use.the.brown.coloration.to.hide.completely.and.use.the.
blue.coloration.to.startle.predators.

9.2.3 Mechanism of Structural Color

Lord.Rayleigh.was.one.of.the.irst.researchers.to.recognize.the.structural.color.phenomena.
in. the. early. 1920s. (Rayleigh. 1917,. 1919).. He. observed. iridescent. animals. under. a. micro-
scope. and. found. that. when. light. was. relected. off. the. wings. of. a. Morpho . butterly. the.
wings. appeared. blue-greenish;. however,. the. light. that. passed. through. the. wings. was.
brown.(Kinoshita.and.Yoshioka.2005)..The.development.of.the.scanning.electron.micro-
scope. (SEM). enabled. the. observation. of. the. nanostructure. of. the. butterly. wing. scale..
Yoshioka.and.Kinoshita.observed.the.cross.section.of.the.wing.scale.via.SEM.(Yoshioka.
and.Kinoshita.2004)..Separated.ridges.with.lamellar.structures.and.membranes.between.
them.were.revealed.(Figure.9.2)..Without.the.cover.scale,.the.light.would.be.relected.from.
the.brown.pigment.embedded.in.the.relective.ground.scale.
The. cover. scale. is. able. to. produce. a. shimmering. effect. on. the. relective. scale. by.
using.a.quasi.multilayer.interference.to.produce.vibrant.structural.colors..In.1917,.Lord.

5 kV 1 μm × 15,000

Figure 9.2
SEM. image. of. cross. section. of. the. Morpho . wing. scale.. (Reproduced. by. kind. permission. of. Shinya. Yoshioka,.
Osaka.University:.http://www.sciencebuzz.org/buzz_tags/nanotechnology).