Chemistry Reference
In-Depth Information
a
b
p
R
core
~
Φ
ion
2/5
−
Φ
ion
6
~
~
2
Φ
ion
Φ
ion
−
6/5
~
Φ
ion
−
1/5
~
~
Φ
ion
H
corona
Φ
ion
Φ
ion
c
d
~
α
b
2/11
p
R
core
−
6
α
b
~
α
b
α
b
−
2
~
unimers
−12/11
~
α
b
~
H
corona
α
b
~
−4/11
unimers
α
b
α
b
Fig. 8
Dependency of (
a
) aggregation number
p
;(
b
) radius of the core
R
core
and thickness of
the corona
H
corona
in crew-cut spherical micelles with pH-sensitive coronal block as a function of
salt concentration. The pH is fixed according to the position of the vertical dotted arrow in Fig.
5
.
Dependency of (
c
)
p
,and(
d
)
R
core
and
H
corona
as a function of pH. Salt concentration is fixed
according to the position of horizontal dotted arrow in Fig.
7
α
≈
α
b
, but the electrostatic interactions are strongly screened due to high salt con-
centration, and structural parameters of the micelles are the same as in region CC
qn
.
Line
Φ
(
1
)
ion
separates regions CC
qn
and CC
osm
. The bold line indicates the transi-
Φ
ion
=
Φ
ion
(
α
b
)
tion line
, where weakly ionized osmotic crew-cut micelles abruptly
transform into strongly charged starlike micelles (region
S
ch
)
.InregionCC
ch
,
the
Φ
(
2
)
charged micelles acquire crew-cut shape. Line
ion
separates regions CC
osm
from
CC
ch
. Upon crossing this line, a continuous transformation of micelles occurs.
The evolution in aggregation number, core radius, degree of dissociation, and
extension of the coronal chains in a crew-cut micelle, as a function of salt concen-
tration and pH
In contrast to a nonmonotonous behavior of the equilibrium parameters of crew-
cut micelles, the CMC decreases monotonously as a function of the bulk salt
concentration,
,
Φ
ion
. Namely:
ln CMC
CC
=
−
γ
(
2
/
3
N
B
/
ϕ
)
,
Φ
ion
Φ
(
2
)
N
A
[
α
b
Φ
ion
/
γ
(
2
−
N
A
ln
(
1
−
α
b
)
−
1
−
α
b
)]
ion
,
+
(123)
N
3
/
5
A
(
2
)
ion
2
/
5
2
b
2
/
5
(
v
A
+
α
/
)
,
Φ
.
γ
2
Φ
Φ
ion
ion
Search WWH ::
Custom Search