Biomedical Engineering Reference
In-Depth Information
characteristics.of.the.natural.butterly.wings..The.CEFR.technique.will.be.useful.for.fabri-
cating.highly.eficient,.biomimetic.optical.devices.
9.3.7 SnO
2
Wing Structure by Sol-gel Process
SnO
2
. is. one. of. the. promising. materials. for. optical. and/or. electronic. devices. due. to.
its. unique. properties,. e.g.,. optical. transmission,. electrical. conduction,. and. infrared.
relection.(Mulla.et.al..1986,.Presley.et.al..2004)..Song.et.al..synthesized.SnO
2
.replicas.of.
the. hierarchical. structures. of. butterly. wings. using. the. sol-gel. soaking. process. (Song.
et.al..2009)..
Euploea
.butterly.wings.were.immersed.in.anhydrous.ethanol.for.5.min.and.
soaked.in.a.Sn-colloid.system.for.14.h..After.being.dried.at.60°C.for.60.min,.the.sample.
was.put.in.an.oxidation.oven.and.heated.up.to.550°C.at.a.rate.of.2°C/min.followed.by.
calcination.for.90.min.in.the.oven.to.burn.off.the.original.wing.template..It.turns.out.that.
the. SnO
2
. wing. replicas. exhibited. well-organized. macroporous. frameworks,. connective.
hollow. interiors,. and. thin. mesoporous. walls. with. less-agglomerated. microstructures,.
which. demonstrated. high. sensitivity. to. ethanol. (Song. et. al.. 2009). and. enhanced. UV.
relection.(Song.et.al..2011).
9.3.8 Magneto-Optic Wing by Hydrothermal Process
In.order.to.incorporate.the.magnetic.function.into.the.biomimetic.butterly.wing.structure,.
amagneto-optic.Fe
3
O
4
.hierarchical.structure.has.been.fabricated.through.the.hydrothermal.
process.. The. hydrothermal. process. was. initially. used. for. heterogeneous. deposition. of.
CdS. nanoparticles,. followed. by. the. activation. of. the. original. wing. template. by. using.
an. ethylene-diaminetetraacetic. acid. (EDTA). in. dimethylformamide. (DMF). suspension.
(Han. et. al.. 2009).. The. CdS. wing. precisely. replicates. the. details. of. the. natural. butterly.
structure. at. both. the. macroscale. (determined. by. the. wing-scale. hierarchy). and. the.
nanoscale. (assembled. patterns. of. nano-CdS. small. clusters).. Peng. et. al.. (2011). further.
incorporated.Fe
3
O
4
.into.the.biomimetic.hierarchical.structure.of.the.butterly.wing.through.
the.hydrothermal.process..First,.the.wing.templates.were.treated.with.EDTA/DMF.to.get.
COO-. activation. sites,. which. served. as. the. nucleation. sites. of. Fe
3
O
4
.. Second,. H
2
O
2
. was.
added. to. FeSO
4
,. forming. a. homogeneous. solution.. Finally,. the. activated. wing. template.
was.soaked.in.the.homogeneous.solution,.put.in.an.autoclave.and.heated.at.160°C.for.5.h..
The.resulting.Fe
3
O
4
.displayed.the.magnetic.and.optical.response.that.they.were.intended.
to.. The. hydrothermal. process. provides. a. simple. and. low-cost. approach. to. the. faithful.
replication.of.the.hierarchical.structure.of.butterly.wings.
9.3.9 Photonic Crystals by ultrasonication
Alternatively,. photonic. crystals. have. been. synthesized. in. semiconductors. (TiO
2
,. SnO
2
,.
and.SiO
2
).using.a.simple.ultrasonication.method.(Zhu.et.al..2009,.Liu.et.al..2010)..Briely,.
wing. templates. were. irst. treated. with. HCl. and. NaOH. solutions,. soaked. in. carefully.
selected. ethanol/water/precursor. solutions. and. sonicated. at. room. temperature. using. a.
high-intensity.ultrasonic.probe.for.2.5-3.h..After.being.washed.and.dried.overnight.under.
vacuum,.calcination.was.performed.at.500°C.for.3.h..Metal.oxide.replicas.in.the.form.of.
ceramic.butterly.wings.were.synthesized.by.following.this.methodology.
Tang.et.al..(2012).further.extended.this.ultrasonication.approach.to.a.polymer.replica.of.
butterly.wings.using.polypyrrole.through.two.steps..It.now.includes.a.two-step.templating.
