Biomedical Engineering Reference
In-Depth Information
Multilayer
interference
Incoherence
Diffraction
Large difference in
high reflectivity
broadband reflection
Pigmentation
Enhancement of blue color
change of hue
Figure 9.4
Schematics. of. lamellar. structures. and. their. optic. features. in. a.
Morpho
. butterly. wing.. (Kinoshita,. S.. and.
Yoshioka,.S.:.Structural.colors.in.nature:.The.role.of.regularity.and.irregularity.in.the.structure..
ChemPhysChem
..
2005.. 6.. 1442-1459.. Copyright. Wiley-VCH. Verlag. Gmbh. &. Co.. KGaA.. Reproduced. with. modiication. with.
permission.)
and.small.bandwidth.as.found.in.an.ideal.multilayer..In.summary,.the.nanostructures.on.
the.top-layer.transparent.scales.can.diffuse.or.spread.out.the.relective.light.with.varying.
degrees. of. order. and. disorder.. Altogether,. butterly. wings. produce. structural. color. by.
photonic.nanostructures,.relection,.diffraction,.and.interference.(Kinoshita.et.al..2002).
9.3 Biomimetic Butterfly Wing Scale Structures
Inspired. by. butterly. wings,. biomimetic. hierarchical. structures. have. been. successfully.
fabricated. by. templating. the. scales. and. imbricating. the. wings. using. various. materials,.
including. semiconductors. and. metal. oxides. (e.g.,. SiO
2
,. TiO
2
,. SnO,. Al
2
O
3
,. ZnO,. Fe
3
O
4
),.
carbon,.phosphor,.glass,.and.polymers..Most.of.the.biomimetic.hierarchical.structures.use.
natural.butterly.wings.as.a.template.and.are.fabricated.by.various.deposition.and.synthesis.
methods,. such. as. chemical. vapor. deposition,. solution. casting,. atomic. layer. deposition,.
soaking. process,. conformal-evaporated-ilm-by-rotation,. sol-gel. process,. hydrothermal.
process,. ultrasonication,. and. molding. lithography.. Direct. write. (such. as. electron. beam.
lithography.and.laser.direct-write).provides.a.new.avenue.to.fabricate.biomimetic.tree-like.
structures.without.the.need.of.a.butterly.wing..These.methods.have.been.summarized.in.
Table.9.1.and.outlined.as.follows.
9.3.1 Synthetic Silica Wing by Chemical Vapor Deposition
Cook.et.al..irst.replicated.the.biomimetic.butterly.wing.using.chemical.vapor.deposition.
(CVD).of.silica.(Cook.et.al..2003)..A.peacock.butterly.wing.structure.was.used.as.a.bio-
template,.on.which.the.silane.was.oxidized.with.hydrogen.peroxide.in.the.vapor.phase.in.
a.controlled.manner.to.produce.a.thin.silica.coating.in.a.CVD.apparatus..The.thin.silica.
coating. could. serve. as. the. ixative. and. conserve. the. delicate. structure. of. the. biospeci-
men,.followed.by.removing.the.biotemplate.through.calcination.(combustion.at.550°C)..By.
this.method,.a.precise.replica.of.the.original.wing.structure.was.obtained.using.synthetic.
