<s>
Polythiophenes	B-Algorithm
(	O
PTs	O
)	O
are	O
polymerized	O
thiophenes	O
,	O
a	O
sulfur	O
heterocycle	O
.	O
</s>
<s>
PTs	O
become	O
conductive	B-Algorithm
when	O
oxidized	O
.	O
</s>
<s>
The	O
electrical	O
conductivity	O
results	O
from	O
the	O
delocalization	O
of	O
electrons	O
along	O
the	O
polymer	B-Language
backbone	O
.	O
</s>
<s>
Changes	O
in	O
both	O
color	O
and	O
conductivity	O
are	O
induced	O
by	O
the	O
same	O
mechanism	O
,	O
twisting	O
of	O
the	O
polymer	B-Language
backbone	O
and	O
disrupting	O
conjugation	O
,	O
making	O
conjugated	O
polymers	B-Language
attractive	O
as	O
sensors	O
that	O
can	O
provide	O
a	O
range	O
of	O
optical	O
and	O
electronic	O
responses	O
.	O
</s>
<s>
The	O
development	O
of	O
polythiophenes	B-Algorithm
and	O
related	O
conductive	B-Algorithm
organic	O
polymers	B-Language
was	O
recognized	O
by	O
the	O
awarding	O
of	O
the	O
2000	O
Nobel	O
Prize	O
in	O
Chemistry	O
to	O
Alan	O
J	O
.	O
Heeger	O
,	O
Alan	O
MacDiarmid	O
,	O
and	O
Hideki	O
Shirakawa	O
"	O
for	O
the	O
discovery	O
and	O
development	O
of	O
conductive	B-Algorithm
polymers	I-Algorithm
"	O
.	O
</s>
<s>
PT	O
is	O
an	O
ordinary	O
organic	O
polymer	B-Language
,	O
being	O
a	O
red	O
solid	O
that	O
is	O
poorly	O
soluble	O
in	O
most	O
solvents	O
.	O
</s>
<s>
Upon	O
treatment	O
with	O
oxidizing	O
agents	O
(	O
electron-acceptors	O
)	O
however	O
,	O
the	O
material	O
takes	O
on	O
a	O
dark	O
color	O
and	O
becomes	O
electrically	O
conductive	B-Algorithm
.	O
</s>
<s>
Around	O
0.2	O
equivalent	O
of	O
oxidant	O
is	O
used	O
to	O
convert	O
PTs	O
(	O
and	O
other	O
conducting	B-Algorithm
polymers	I-Algorithm
)	O
into	O
the	O
optimally	O
conductive	B-Algorithm
state	O
.	O
</s>
<s>
Because	O
of	O
the	O
redox	O
reaction	O
,	O
the	O
conductive	B-Algorithm
form	O
of	O
polythiophene	B-Algorithm
is	O
a	O
salt	O
.	O
</s>
<s>
The	O
bipolaron	O
moves	O
as	O
a	O
unit	O
along	O
the	O
polymer	B-Language
chain	O
and	O
is	O
responsible	O
for	O
the	O
macroscopically	O
observed	O
conductivity	O
of	O
the	O
material	O
.	O
</s>
<s>
Iodine	O
and	O
bromine	O
produce	O
highly	O
conductive	B-Algorithm
materials	O
,	O
which	O
are	O
unstable	O
owing	O
to	O
slow	O
evaporation	O
of	O
the	O
halogen	O
.	O
</s>
<s>
The	O
effective	O
conjugation	O
length	O
of	O
polythiophene	B-Algorithm
derivatives	O
depend	O
on	O
the	O
chemical	O
structure	O
of	O
side	O
chains	O
,	O
and	O
thiophene	O
backbones	O
.	O
</s>
<s>
PTs	O
exhibit	O
absorption	O
shifts	O
due	O
to	O
application	O
of	O
electric	O
potentials	O
(	O
electrochromism	B-Algorithm
)	O
,	O
or	O
to	O
introduction	O
of	O
alkali	O
ions	O
(	O
ionochromism	O
)	O
.	O
</s>
<s>
Polythiophene	B-Algorithm
and	O
its	O
oxidized	O
derivatives	O
have	O
poor	O
processing	O
properties	O
.	O
</s>
<s>
Nonetheless	O
,	O
intense	O
interest	O
has	O
focused	O
on	O
soluble	O
polythiophenes	B-Algorithm
,	O
which	O
usually	O
translates	O
to	O
polymers	B-Language
derived	O
from	O
3-alkylthiophenes	O
,	O
which	O
give	O
the	O
so-called	O
polyalkylthiophenes	O
(	O
PATs	O
)	O
.	O
</s>
<s>
Soluble	O
polymers	B-Language
are	O
derivable	O
from	O
3-substituted	O
thiophenes	O
where	O
the	O
3-substituent	O
is	O
butyl	O
or	O
longer	O
.	O
</s>
<s>
One	O
undesirable	O
feature	O
of	O
3-alkylthiophenes	O
is	O
the	O
variable	O
regioregularity	O
of	O
the	O
polymer	B-Language
.	O
</s>
<s>
Focusing	O
on	O
the	O
polymer	B-Language
microstructure	O
at	O
the	O
dyad	O
level	O
,	O
3-substituted	O
thiophenes	O
can	O
couple	O
to	O
give	O
any	O
of	O
three	O
dyads	O
:	O
</s>
<s>
PATs	O
prepared	O
using	O
Rieke	O
zinc	B-Application
formed	O
"	O
crystalline	O
,	O
flexible	O
,	O
and	O
bronze-colored	O
films	O
with	O
a	O
metallic	O
luster	O
"	O
.	O
</s>
<s>
On	O
the	O
other	O
hand	O
,	O
the	O
corresponding	O
regiorandom	O
polymers	B-Language
produced	O
"	O
amorphous	O
and	O
orange-colored	O
films	O
"	O
.	O
</s>
<s>
Comparison	O
of	O
the	O
thermochromic	O
properties	O
of	O
the	O
Rieke	O
PATs	O
showed	O
that	O
,	O
while	O
the	O
regioregular	O
polymers	B-Language
showed	O
strong	O
thermochromic	O
effects	O
,	O
the	O
absorbance	O
spectra	O
of	O
the	O
regioirregular	O
polymers	B-Language
did	O
not	O
change	O
significantly	O
at	O
elevated	O
temperatures	O
.	O
</s>
<s>
The	O
difference	O
between	O
absorption	O
and	O
emission	O
maxima	O
,	O
the	O
Stokes	B-Algorithm
shift	I-Algorithm
,	O
also	O
increases	O
with	O
HH	O
dyad	O
content	O
,	O
which	O
they	O
attributed	O
to	O
greater	O
relief	O
from	O
conformational	O
strain	O
in	O
the	O
first	O
excited	O
state	O
.	O
</s>
<s>
Water-soluble	O
PT	O
's	O
are	O
represented	O
by	O
sodium	O
poly(3-thiophenealkanesulfonate )	O
s	O
.	O
In	O
addition	O
to	O
conferring	O
water	O
solubility	O
,	O
the	O
pendant	O
sulfonate	O
groups	O
act	O
as	O
counterions	O
,	O
producing	O
self-doped	O
conducting	B-Algorithm
polymers	I-Algorithm
.	O
</s>
<s>
Fluorinated	O
polythiophene	B-Algorithm
yield	O
7%	O
efficiency	O
in	O
polymer-fullerene	O
solar	O
cells	O
.	O
</s>
<s>
The	O
3	O
,	O
4-disubstituted	O
thiophene	O
called	O
ethylenedioxythiophene	O
(	O
EDOT	O
)	O
is	O
the	O
precursor	O
to	O
the	O
polymer	B-Language
PEDOT	B-Algorithm
.	O
</s>
<s>
PEDOT	B-Algorithm
is	O
found	O
in	O
electrochromic	B-Algorithm
displays	I-Algorithm
,	O
photovoltaics	O
,	O
electroluminescent	O
displays	O
,	O
printed	O
wiring	O
,	O
and	O
sensors	O
.	O
</s>
<s>
In	O
an	O
electrochemical	O
polymerization	O
,	O
a	O
solution	O
containing	O
thiophene	O
and	O
an	O
electrolyte	O
produces	O
a	O
conductive	B-Algorithm
PT	O
film	O
on	O
the	O
anode	O
.	O
</s>
<s>
Electrochemical	O
polymerization	O
is	O
convenient	O
,	O
since	O
the	O
polymer	B-Language
does	O
not	O
need	O
to	O
be	O
isolated	O
and	O
purified	O
,	O
but	O
it	O
can	O
produce	O
polymers	B-Language
with	O
undesirable	O
alpha-beta	O
linkages	O
and	O
varying	O
degrees	O
of	O
regioregularity	O
.	O
</s>
<s>
The	O
degree	O
of	O
polymerization	O
and	O
quality	O
of	O
the	O
resulting	O
polymer	B-Language
depends	O
upon	O
the	O
electrode	O
material	O
,	O
current	O
density	O
,	O
temperature	O
,	O
solvent	O
,	O
electrolyte	O
,	O
presence	O
of	O
water	O
,	O
and	O
monomer	O
concentration	O
.	O
</s>
<s>
2	O
,	O
5-Dibromo-3-alkylthiophene	O
when	O
treated	O
with	O
highly	O
reactive	O
"	O
Rieke	O
zinc	B-Application
"	O
is	O
an	O
alternative	O
method	O
.	O
</s>
<s>
Exhaustive	O
Soxhlet	O
extraction	O
after	O
polymerization	O
with	O
polar	O
solvents	O
was	O
found	O
to	O
effectively	O
fractionate	O
the	O
polymer	B-Language
and	O
remove	O
residual	O
catalyst	O
before	O
NMR	O
spectroscopy	O
.	O
</s>
<s>
Higher-quality	O
catalyst	O
,	O
added	O
at	O
a	O
slower	O
rate	O
and	O
at	O
reduced	O
temperature	O
,	O
was	O
shown	O
to	O
produce	O
high	O
molecular	O
weight	O
PATs	O
with	O
no	O
insoluble	O
polymer	B-Language
residue	O
.	O
</s>
<s>
Given	O
the	O
difficulties	O
of	O
studying	O
a	O
system	O
with	O
a	O
heterogeneous	O
,	O
strongly	O
oxidizing	O
catalyst	O
that	O
produces	O
difficult	O
to	O
characterize	O
rigid-rod	O
polymers	B-Language
,	O
the	O
mechanism	O
of	O
oxidative	O
polymerization	O
is	O
by	O
no	O
means	O
decided	O
.	O
</s>
<s>
As	O
an	O
example	O
of	O
a	O
static	O
application	O
,	O
poly(3,4-ethylenedioxythiophene )	O
-poly(styrene sulfonate )	O
(	O
PEDOT-PSS	O
)	O
product	O
(	O
"	O
Clevios	O
P	O
"	O
)	O
from	O
Heraeus	O
has	O
been	O
extensively	O
used	O
as	O
an	O
antistatic	O
coating	O
(	O
as	O
packaging	O
materials	O
for	O
electronic	O
components	O
,	O
for	O
example	O
)	O
.	O
</s>
<s>
AGFA	O
coats	O
200	O
m	O
×	O
10	O
m	O
of	O
photographic	O
film	O
per	O
year	O
with	O
PEDOT:PSS	B-Algorithm
because	O
of	O
its	O
antistatic	O
properties	O
.	O
</s>
<s>
The	O
thin	O
layer	O
of	O
PEDOT:PSS	B-Algorithm
is	O
virtually	O
transparent	O
and	O
colorless	O
,	O
prevents	O
electrostatic	O
discharges	O
during	O
film	O
rewinding	O
,	O
and	O
reduces	O
dust	O
buildup	O
on	O
the	O
negatives	O
after	O
processing	O
.	O
</s>
<s>
PEDOT	B-Algorithm
also	O
has	O
been	O
proposed	O
for	O
dynamic	O
applications	O
where	O
a	O
potential	O
is	O
applied	O
to	O
a	O
polymer	B-Language
film	O
.	O
</s>
<s>
PEDOT-coated	O
windows	O
and	O
mirrors	O
become	O
opaque	O
or	O
reflective	O
upon	O
the	O
application	O
of	O
an	O
electric	O
potential	O
,	O
a	O
manifestation	O
of	O
its	O
electrochromic	B-Algorithm
properties	I-Algorithm
.	O
</s>
<s>
Widespread	O
adoption	O
of	O
electrochromic	B-Algorithm
windows	O
promise	O
significant	O
savings	O
in	O
air	O
conditioning	O
costs	O
.	O
</s>
<s>
In	O
general	O
,	O
two	O
categories	O
of	O
applications	O
are	O
proposed	O
for	O
conducting	B-Algorithm
polymers	I-Algorithm
.	O
</s>
<s>
Dynamic	O
applications	O
utilize	O
changes	O
in	O
the	O
conductive	B-Algorithm
and	O
optical	O
properties	O
,	O
resulting	O
either	O
from	O
application	O
of	O
electric	O
potentials	O
or	O
from	O
environmental	O
stimuli	O
.	O
</s>
<s>
Polythiophenes	B-Algorithm
show	O
potential	O
in	O
the	O
treatment	O
of	O
prion	O
diseases	O
.	O
</s>
