Environmental Engineering Reference
In-Depth Information
of.fullerenes.merited.a.Nobel.Prize.award.to.Dr..Richard.Smalley,.Dr..Robert.Curl,.
and.Dr..Harold.Kroto.in.1996.[28]..Much.of.this.work.occurred.at.Rice.University.
in.Texas,.leading.the.legislature.of.the.State.of.Texas.to.designate,.in.1997,.that.the.
buckminsterfullerene.is.the.oficial.State.Molecule.of.Texas.[29].
The.C60.fullerene.is.the.most.common.form,.followed.by.C70;.higher.fullerenes.
include. C74,. C76,. C78,. C80,. C82,. C84,. and. C86. through. C96.. Variations. on. the.
fullerene.structure.include.[30]:
•
Endohedral or incarfullerenes.
. These. fullerenes. entrap. (or.
incar
cerate).
elements.or.molecules.within.the.carbon.matrix.
Multi-walled or nested fullerenes.
. These. particles. comprise. two. or. more.
nested.fullerenes.
Heterofullerenes.
.In.these.fullerenes,.an.atom.such.as.boron,.nitrogen,.or.
phosphorous.replaces.one.or.more.carbon.atoms.in.the.fullerene.
•
•
The.properties.of.fullerenes.depend.on.the.structure,.derivatization,.and.degree.
of.agglomeration..In.general,.pure.fullerenes.have.low.solubility.in.water..Under.cer-
tain.conditions,.fullerenes.will.form.polymorphic.hexagonal.unit.cell.agglomerates.
in.water.referred.to.as.nano-C60..These.agglomerates,.approximately.25.to.500.nm.
in.size,.carry.a.strong.negative.charge..Scientists.have.detected.fullerenes.in.ancient.
geologic.formations,.suggesting.that.they.can.originate.from.natural.sources.as.well.
as.manufacturing.processes,.and.that.fullerenes.can.be.extraordinarily.stable.under.
geologic.conditions.[31].
Fullerenes.are.electron.deicient.and.can.react.with.nucleophilc.species..They.are.
not.oxidized.readily,.although.in.the.presence.of.oxygen.and.light,.oxidative.degrada-
tion.of.C60.to.C
120
O.occurs..The.larger.fullerenes.are.less.reactive.than.C60.[30].
Possible.applications.for.fullerenes.include.catalysts.and.sensors;.nanocompos-
ites.containing.fullerenes.can.be.used.in.optics.and.photochemistry.applications,.and.
endohedral. fullerenes. also. can. be. used. as. medical. therapeutic. agents. [32].. Of. the.
eight.commercial.products.listed.in.the.Nanotechnology.Consumer.Products.Inven-
tory. [1]. as. containing. carbon. fullerenes,. seven. are. cosmetics. products. and. one. is.
sports.equipment..Some.of.the.cosmetic.products.tout.the.ability.of.C60.fullerenes.
to.scavenge.free.radicals.
. suMMaRY
Nanomaterials.share.the.characteristic.that.they.are.between.1.and.100.nm.in.at.least.
one.dimension..As.a.result.of.this.small.size,.the.physical.and.chemical.properties.of.
nanoparticles.can.differ.from.those.of.the.same.material.in.bulk.form..The.smaller.
size.means.that.the.relative.surface.area.of.the.particle.is.larger.and.therefore.its.rela-
tive.reactivity.increases..For.some.materials,.the.ability.of.an.atom.or.molecule.to.
absorb.or.emit.energy.in.quanta.begins.to.inluence.the.nanomaterial's.behavior.
Beyond.those.generalizations,.however,.nanomaterials.vary.widely.in.terms.of.
their.composition,.properties,.and.uses..To.bring.focus.to.discussions.of.nanotech-
nology.and.the.environment,.this.topic.focuses.on.six.engineered.nanomaterials:
