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Complex Fluids GroupUniversity of São Paulo,
Brazil
LYO-BANANA MESOPHASES COMPOSED BY A MIXTURE OF APOLAR SOLVENTS AND BENT-
SHAPED MOLECULES
O. G. Martins1, Y. Huang2, A. Jákli2, H. Sawade2 e A. M. Figueiredo Neto1
1Instituto de Física, Universidade de São Paulo, Brazil2Liquid Crystal Institute, Kent State University, USA
Complex Fluids GroupUniversity of São Paulo,
Brazil
Molecules with the “form” of
H
N
O
O
RR
N
O
O
H
R R
O
O
H H
N N
O
O
H
N
O
O
O O
N
O
O
H
9’
10’
128
5
1
23
4
67
9
1011
B
AA’
B ’
long axis C
1996
1925
Complex Fluids GroupUniversity of São Paulo,
Brazil
(+) Chirality
Synclin icAntiferro
Anticlin icFerro
Anticlin icAntiferro
Synclin icFerro
Racemic
E = 0 E = 0E < -E t h E < -E thE > E th E > E th
C
z
z
bn
c
b
BA Homogeneouslychiral
(- ) Chirality
Complex Fluids GroupUniversity of São Paulo,
Brazil
a
c B1 phase of the “smectic type”
k
m
n n
n
n
n
n
n
n
m
m
m
m
m
m
m
C P
C B2
C B1
C G
z
y x
z
Complex Fluids GroupUniversity of São Paulo,
Brazil
Bi ,with i from 1 to 7
B2 B5 smectic, with 2D rectangular ordering in the layers
1) With ferroelectric switching
(symmetry C2v), smectic
2) 2D ordering
B1 smectic, with 2D rectangular ordering in the layers
B7 structure not well determined [probably of the type
1) above]
Complex Fluids GroupUniversity of São Paulo,
Brazil
3) phases with intercalated molecules
B6 smectic , with tilted molecules
4) Crystalline phases
B3 and B4
Complex Fluids GroupUniversity of São Paulo,
Brazil
xilene molecular mass: 108
Complex Fluids GroupUniversity of São Paulo,
Brazil
B7 phase in the temperaturerange from 90 to 133oC
Smectic with spacing layer of38.5Å, and a complex in-layerstructure. Helical filaments atthe transition from the ISO phase.-“telephone-wire-like” texture
Complex Fluids GroupUniversity of São Paulo,
Brazil
xilene weaken the dipole-dipole interaction
Complex Fluids GroupUniversity of São Paulo,
Brazil
C10H21 named C10 C14H29 named C14
Cr B2 ISO
68oC 127oC
118oC 140oC
C14
C10
In São Paulo and Kent
Complex Fluids GroupUniversity of São Paulo,
Brazil
The solvent
n – hexadecane: CH3 – (CH2)14 - CH3
boiling point: 287oCdensity: 0.77g/cm3
molecular weight: 226.4
Doping (in weight %): 20 and 40
Complex Fluids GroupUniversity of São Paulo,
Brazil
C10 ,T=22oC
Crystalline phase
X Ray Diffraction
4.4 Å51.4 Å
C14 ,T=23oCd
b
Complex Fluids GroupUniversity of São Paulo,
Brazil
C14 ,T=23oC, 20wt%
B3 phase, oriented
d = 54.7Å > d0 wt%
b = 4.6Å b0 wt%
hexadecane
Complex Fluids GroupUniversity of São Paulo,
Brazil
C14 ,T=79oC, 20wt%
B3 phase, non oriented
d = 55.6Å > d0 wt%
b = 4.6Å b0 wt%
Complex Fluids GroupUniversity of São Paulo,
Brazil
C14 ,T=23oC, 40wt%
C14 ,T=79oC, 40wt%
Complex Fluids GroupUniversity of São Paulo,
Brazil
0.0e+0
0.2e-3
0.5e-3
0.7e-3
1.0e-3
0.1e-2
0.1e-2
Inte
nsit
y (
I )
3 4 5 6 7 8 9d [A°]
0.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
Inte
nsit
y (
I )
10 20 30 40 50 60 70 80d [A°]
C14 ,T=80oC, 0wt%
B2 phase
Complex Fluids GroupUniversity of São Paulo,
Brazil
C14 ,T=25oC, 20wt%
B3 phase0.0e+0
1.0e-3
0.2e-2
0.3e-2
0.4e-2
0.5e-2
0.6e-2
0.7e-2
0.8e-2
Inte
nsit
y (
I )
20 30 40 50 60 70 80 90d [A°]
0.0e+0
1.0e-4
0.2e-3
0.3e-3
0.4e-3
0.5e-3
0.6e-3
0.7e-3In
tens
ity
( I
)
3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5d [A°]
Complex Fluids GroupUniversity of São Paulo,
Brazil
1) The doping with 20 and 40 wt % of hexadecane
2) The doping with xilene (p and m)
a) stabilized a B3 phase
b) destabilized the B2 phase
a) Reduced the clearing point
b) Reduced the transition enthalpy
Complex Fluids GroupUniversity of São Paulo,
Brazil
Complex Fluids GroupUniversity of São Paulo,
Brazil