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Bacterial Cellulose
Introduction
Intrinsically.conducting.polymers.(ICPs),.also.referred.to.as.synthetic.. metals.
or.organic.semiconductors,.are.materials.that.display.the.electrical.and.optical.
properties.of.metals.or.semiconductors.while.retaining.some.of.the.mechanical.properties.and.processing.advantages.of.polymers..Indeed,.ICPs.allow.a.
wide.range.of.freedom.in.the.formulation.of.materials.with.varying.degrees.
of.conductivity,.from.very.low.to.very.high,.ranges.unmatched.with.the.use.
of.metals..This.special.class.of.polymers.has.been.studied.extensively.due.to.
their.scientific.importance.in.many.research.areas.and.emerging.technological.applications,.with.some.conducting.polymers.already.being.produced.on.
a.commercial.scale.by.several.industries.(Bernhard.1997;.Song.and.Palmore.
2006).. Their. distinct. intrinsic. properties. and. characteristics. have. shown.
strong.potential.for.use.in.a.wide.range.of.applications.that.can.be.grouped.
into.two.main.areas..The.first.concerns.the.use.of.their.electrically.conductive.properties.to.produce.electromagnetic.shielding.(Joo.and.Epstein.1994),.
printed.circuit.boards.(Meyer.et.al..1994),.artificial.nerves.(Baughman.1996),.
and.antistatic.clothing.(Dall’Acqua.et.al..2004)..In.a.second.area,.their.electroactive. properties. are. called. into. play. for. applications. such. as. ion. exchange.
membranes.(Nagarale.et.al..2006),.energy.storage.devices.(Song.and.Palmore.
2006;.Wang.et.al..2010),.molecular.electronics.(Akkerman.et.al..2006),.. electrical.
displays.(Mortimer.et.al..2006),.electrochemical.actuators.(Lewis.et.al..1999),.
drug.release.systems.(Svirskis.et.al..2010),.sensory/biosensory.devices.(Becerik.
and. Kadirgan. 2001;. Ramanavic ˇius. et al.. 2006),. tissue. engineering. scaffolds.
(Kim. et. al.. 2004). and. neural. probes. (Guimard. et. al.. 2007;. Ravichandran.
et al..2010)..A.graphic.representation.(Figure 12.1).of.a.query.using.the.term.
“. conducting.polymers”.under.“topic”.on.the.Thomson.Reuters.(formerly.ISI).
Web.of.Knowledge.database,.as.well.as.on.EspaceNet,.shows.the.increasing.
number. of. published. manuscripts. and. patents. in. the. last. decade.. Further.
breakdown.of.the.search.term.according.to.specific.categories.(Figure 12.2).
shows. that. during. this. decade. the. major. area. of. (potential). applications. of.
ICPs.concerns.the.development.of.sensors..This.is.followed.by.the.development. of. membrane. units. almost. in. parallel. with. corrosion. prevention. systems..A.third.place.would.be.occupied.by.energy.storage.devices.(batteries).
The.unique.electronic.structural.feature.of.ICPs.is.characterized.by.the.occurrence.of.a.conjugated.π-electron.system.along.the.main.chain.(Figure 12.3a)..
The.designation.of.“conjugated”.polymer.is.related.to.the.presence.of.alternating.single.and.double.bonds.in.the.polymer.chain..Doping.is.the.unique,.
central,.and.unifying.concept.that.distinguishes.conducting.polymers.from.
all.other.types.of.polymers:.the.bonding.π.system.of.the.polymer.backbone.
can. be. oxidized. (p-doping). or. reduced. (n-doping). chemically. or. electrochemically.to.the.metallic.state.more.easily.than.with.. conventional.polymers..
During. the. doping. process. (Figure 12.3b),. counterions. called. .
dopants. are.
inserted.into.the.polymer.backbone.and.the.conjugated.polymer.(nondoped.