Figure 6.4
NOC
A
2 nm
0.46 nm
~30°
0.46 nm
NOC surface
A
Hydrophobic site
0.66 nm
Tilted glucose ring planes
120
Bacterial Cellulose
Figure 6.4
matic.cross-section.image.perpendicular.(lateral.direction).to.the.stretching.direction.indicating.the.tilted.arrangement.of.glucan.chains..The.film.was.negatively.stained.by.uranyl.acetate.
and. spans. a. region. of. the. copper. support. grid.. Note. the. individual. glucan. chains. that. are.
separated. by. an. average. distance. of. 0.66. nm. (arrows).. The. arrangement. of. glucan. chains. is.
clearly.resolved.with.a.width.of.0.46.nm.
than.values.for.any.crystalline.cellulose..The.average.width.of.0.462 nm.from.
the.top.view.is.wider.than.that.of.0.45.nm.of.the.narrow.axis.in.the.anhydroglucose. ring. predicted. from. the. space-filling. model.. This. suggests. tilting.
of. the. glucose. planes. of. a. cellulose. molecule. with. an. angle. of. 29.3°. to. the.
vertical.axis.against.the.surface.of.NOC,.as.shown.in.the.bottom.image.of.
Figure 6.4..It.should.be.noted.that.the.static.sessile.contact.angle.of.a.drop.of.
water.on.the.NOC.surface.is.approximately.72°,.indicating.it.is.fairly.hydrophobic.(E. Togawa.and.T..Kondo,.unpublished.data)..Prior.to.stretching.for.
NOC.preparation,.the.dried.WSC.exhibits.approximately.50°.as.the.contact.
angle.by.the.sessile.drop.method..Thus.the.surface.condition.of.it.is.totally.
altered.by.stretching.to.provide.tilting.of.the.glucose.planes.for.exposure.of.
the.specific.hydrophobic.site,.as.shown.in.Figure 6.4..The.hydro. phobic.phases.
due.to.the.anhydroglucose.plane.appear.alternately.next.to.the.hydrophilic.
OH.tracks,.resulting.in.unique.amphiphilic.molecular.tracks.
Infrared. spectroscopic. analyses. combined. with. other. methods. revealed.
characteristic. features. of. NOC. film. templates. (Hishikawa. et. al.. 2010).. The.
vapor-phase.deuteration.of.the.NOC.film.indicated.that.the.amount.of.unexchangeable.OH.groups,.10.6%,.of.the.total.OH.groups.corresponded.to.the.
NOC
A
2 nm
0.46 nm
~30°
0.46 nm
NOC surface
A
Hydrophobic site
0.66 nm
Tilted glucose ring planes
120
Bacterial Cellulose
Figure 6.4
matic.cross-section.image.perpendicular.(lateral.direction).to.the.stretching.direction.indicating.the.tilted.arrangement.of.glucan.chains..The.film.was.negatively.stained.by.uranyl.acetate.
and. spans. a. region. of. the. copper. support. grid.. Note. the. individual. glucan. chains. that. are.
separated. by. an. average. distance. of. 0.66. nm. (arrows).. The. arrangement. of. glucan. chains. is.
clearly.resolved.with.a.width.of.0.46.nm.
than.values.for.any.crystalline.cellulose..The.average.width.of.0.462 nm.from.
the.top.view.is.wider.than.that.of.0.45.nm.of.the.narrow.axis.in.the.anhydroglucose. ring. predicted. from. the. space-filling. model.. This. suggests. tilting.
of. the. glucose. planes. of. a. cellulose. molecule. with. an. angle. of. 29.3°. to. the.
vertical.axis.against.the.surface.of.NOC,.as.shown.in.the.bottom.image.of.
Figure 6.4..It.should.be.noted.that.the.static.sessile.contact.angle.of.a.drop.of.
water.on.the.NOC.surface.is.approximately.72°,.indicating.it.is.fairly.hydrophobic.(E. Togawa.and.T..Kondo,.unpublished.data)..Prior.to.stretching.for.
NOC.preparation,.the.dried.WSC.exhibits.approximately.50°.as.the.contact.
angle.by.the.sessile.drop.method..Thus.the.surface.condition.of.it.is.totally.
altered.by.stretching.to.provide.tilting.of.the.glucose.planes.for.exposure.of.
the.specific.hydrophobic.site,.as.shown.in.Figure 6.4..The.hydro. phobic.phases.
due.to.the.anhydroglucose.plane.appear.alternately.next.to.the.hydrophilic.
OH.tracks,.resulting.in.unique.amphiphilic.molecular.tracks.
Infrared. spectroscopic. analyses. combined. with. other. methods. revealed.
characteristic. features. of. NOC. film. templates. (Hishikawa. et. al.. 2010).. The.
vapor-phase.deuteration.of.the.NOC.film.indicated.that.the.amount.of.unexchangeable.OH.groups,.10.6%,.of.the.total.OH.groups.corresponded.to.the.