Smectic polymorphism of 4-nonyloxybenzylidene-4′-alkyloxyanilines

Article abstract of DOI:10.1016/j.molstruc.2007.04.029

This paper describes liquid-crystalline polymorphism of the homologous series of 4-nonyloxybenzylidene-4′-alkyloxyanilines. Based on the polarization microscopy (POM, TOA) and the calorimetric (DSC) measurements the following mesophases were detected: nematic, smectic A, smectic C, smectic B, smectic I and smectic G. The presence of these mesophases was confirmed by the miscibility method, using: 4-heptyloxybenzilidene-4′-pentylaniline, 4-hexyl-4′-decyloxyazobenzene and 4-nonyloxybenzilidene-4′-butylaniline as mesophase references. Influence of the alkyl chain length on the type of mesophases and entropic effects of phase transition are discussed.

Full text of DOI:10.1016/j.molstruc.2007.04.029

Available online at www.sciencedirect.com
Journal of Molecular Structure 844–845 (2007) 259–267
www.elsevier.com/locate/molstruc
Smectic polymorphism of 4-nonyloxybenzylidene-40-alkyloxyanilines
1
*
Joanna Godzwon, Monika J. Sienkowska , Zbigniew Galewski
Faculty of Chemistry, University of Wrocław, Joliot-Curie 14, 50-383 Wrocław, Poland
Received 7 March 2007; received in revised form 16 April 2007; accepted 19 April 2007
Available online 27 April 2007
Abstract
This paper describes liquid-crystalline polymorphism of the homologous series of 4-nonyloxybenzylidene-40-alkyloxyanilines. Based
on the polarization microscopy (POM, TOA) and the calorimetric (DSC) measurements the following mesophases were detected: nema-
tic, smectic A, smectic C, smectic B, smectic I and smectic G. The presence of these mesophases was confirmed by the miscibility method,
using: 4-heptyloxybenzilidene-40-pentylaniline, 4-hexyl-40-decyloxyazobenzene and 4-nonyloxybenzilidene-40-butylaniline as mesophase
references. Influence of the alkyl chain length on the type of mesophases and entropic effects of phase transition are discussed.
ꢀ 2007 Elsevier B.V. All rights reserved.
Keywords: Liquid crystals; Nematic; Smectic; Schiff bases; Phase diagrams
1. Introduction
In addition to the mentioned above Schiff bases, very
interesting appear to be azomethines with both alkyloxy
chains, but only compounds with short alkyloxy chain
(until pentyloxy) were described in literature [10–13]. The
methyl derivative with its nematic phase and ethyl deriva-
tive, which showed the presence of nematic phase and three
unknown smectics, were described in 1940 by Weygand
and Gabler [10,11]. Propyl, butyl and pentyl derivatives
were investigated in 1967 by Dave and Patel [12]. The pro-
pyl and butyl derivatives exhibited nematic phase and one
unknown smectic phase. In the pentyl nematic and two
unknown smectic phases were detected. In 1976 Malthete
et al. [13] recognized nematic and smectic A phases in pro-
pyl derivative.
We expect much more interesting liquid-crystalline poly-
morphism among molecules with longer alkyloxy chains.
Recently we described dodecyloxy and decyloxy series [14].
This article reports in great details the mesomorphic
behavior of the full series of 4-nonyloxybenzylidene-40-
alkyloxyanilines (9ꢀn), including derivatives from methyl
to dodecyl. All present mesophases were identified based
on DSC calorimetry and polarization microscopy (POM)
studies. The identification of the smectic phases with higher
order was confirmed by miscibility methods [15], using
three different smectic standards. The influence of the alkyl
Schiff bases (azomethines) belong to the classic type of
molecules with liquid-crystalline properties. They were rec-
ognized early as nematogenic molecules and were inten-
sively investigated until their commercial use in LCD in
1960s. Nowadays these compounds are not interesting in
modern technology due to their sensitivity to moisture
and at the same time their chemical instability. However,
their very rich polymorphism and simple synthesis are still
commonly utilized in the design of new type of molecules
(e.g., metalomesogenes [1], banana-like molecules [2,3],
mesogens with hydrogen bonds [4]).
4-Alkyloxybenzylidene-40-alkylanilines belong to the
most extensively investigated Schiff bases, among which
even hexamorphism was detected [5]. The synthesis of azo-
methines based on 4-alkylbenzylidene unit is more compli-
cated, therefore, only molecules with short alkyl chains
(until heptyl derivative), with only nematic and smectic B
mesophases were described in the literature [6–9].
*
Corresponding author. Tel.: +48 71 3757346; fax: +48 71 3282348.
E-mail address: ZG@chem.uni.wroc.pl (Z. Galewski).
Present address: Department of Chemistry, University of Pennsylva-
1
nia, 231 South 34th Street, Philadelphia, PA 19104, USA.
0022-2860/$ - see front matter ꢀ 2007 Elsevier B.V. All rights reserved.
doi:10.1016/j.molstruc.2007.04.029

260
J. Godzwon et al. / Journal of Molecular Structure 844–845 (2007) 259–267
Table 1
chain length on the mesophase sequence and the entropy of
the phase transition are broadly discussed.
Elemental analysis of 4-nonyloxybenzylidene-40-alkyloxyanilines (9ꢀn)
n
Calculated
Found
C
H
N
C
H
N
2. Experimental
1
2
3
4
5
6
7
8
9
78.19
78.47
78.74
78.99
79.22
79.43
79.63
79.82
80.00
80.17
80.47
8.78
8.99
9.19
9.37
9.54
9.69
9.84
9.98
3.97
3.82
3.67
3.54
3.43
3.31
3.20
3.10
3.01
2.92
2.76
78.23
78.58
78.63
78.93
79.22
79.61
79.54
80.11
79.91
80.02
80.34
8.73
9.14
9.28
9.48
9.63
9.81
9.90
10.07
10.16
10.38
10.43
4.09
3.94
3.83
3.66
3.67
3.46
3.37
3.21
3.13
2.87
2.84
The synthesis of 4-nonyloxybenzylidene-40-alkyloxyani-
lines (9ꢀn) is outlined in Scheme 1. The synthetic method-
ology is described elsewhere [16,17]. All final products were
purified by flash column chromatography, using silica gel
(Fluka 60 Mash) and chloroform as eluent, followed by
the recrystallization from ethanol and heptane. The purity
of all compounds was confirmed by elemental analysis
(Table 1) with the error limit less than 0.3%.
10.11
10.23
10.45
10
12
2.1. Equipment
eter (Black Star 4503 Intelligent Multimeter). The detailed
experimental procedures are published elsewhere [18].
In the phase diagram investigations only mixtures with
strictly defined compositions were used. Very high accuracy
was obtained by using Metller AT20 balance, with accu-
racy of 2 · 10ꢀ6 g.
Calorimetric measurements were performed by using
Perkin-Elmer DSC7 device. Typical heating and cooling
rates were 5 ꢁC minꢀ1. Indium was used as an enthalpy
standard.
Textures were observed by using an OLYMPUS BX60
device with a CCD JVC camera, connected with the PC
computer through an ELSA graphic card. The microscope
was equipped in LINKAM HTM600 hot stage with a
TMS93 temperature regulator. In addition, the communi-
cation between PC computer and microscope was achieved
by using RS232 connection, which was necessary in the
thermo-optic experiments (TOA). TOA experiment relies
on the registration of two signals (temperature from hot
stage and light intensity in the microscope) at the same
time. The first signal is provided by the temperature regu-
lator and the second one by the photodiode at the multim-
3. Results and discussion
3.1. Liquid-crystalline properties
All phase transition parameters (Table 2) were deter-
mined by the DSC calorimetry, the polarization micros-
copy (POM) and the thermo-optic technique (TOA).
Typical DSC and TOA traces are shown in Figs. 1 and 2.
DSC trace in Fig. 1 illustrates thermal behavior of the pro-
pyl (n = 3) derivative. The heating mode showed two
anomalies at 104.7 ꢁC and at 111.5 ꢁC. The former one is
related to the very characteristic melting process with the
large value of the heating effect of 43.2 kJ molꢀ1. The melt-
ing process began at ꢁ5 ꢁC below the melting temperature,
which is indicated by asymmetry of the DSC peak. This
phenomenon is typical for pretransitional behavior, which
is frequently observed in melting processes. The very simi-
lar behavior was observed in thermo-optical measurement
(TOA). The melting process did not appear as a sudden
change of the light intensity going through the microscope,
but it was detected as a smooth transition. The anomaly at
111.5 ꢁC is related to the isotropisation process. This pro-
cess was recorded as a small peak in DSC trace. In TOA
the isotropisation process was observed as the most notice-
able decrease of light intensity, which is related to the dis-
appearing of the optical anisotropy. The cooling mode
appears to be more complex. The temperature range of
nematic phase was broader than in heating mode. Smectic
A mesophase appeared at 94.6 ꢁC, which is 10 ꢁC below the
melting temperature. This phase transition was observed in
DSC spectroscopy as a small calorimetric anomaly much
less pronounced than Iso–N phase transition. TOA scan
showed the transition to smectic A phase as the significant
change of the light intensity. The nearly linear decrease in
HO
NO2
CnH2n+1Br
K2CO3
cyclohexanone
H2n+1CnO
CHO
NO2
HO
C2H5OH
NH2NH2 H2O
Raney nickel
C9H19Br
K2CO3
cyclohexanone
H2n+1CnO
NH2
C9H19O
CHO
C2H5OH
CH3COOH (catalyst)
C9H19O
CH=N
OCnH2n+1
Scheme 1. Synthesis of 4-nonyloxybenzylidene-40-alkyloxyanilines (9-n).

J. Godzwon et al. / Journal of Molecular Structure 844–845 (2007) 259–267
261
Iso
Table 2
Phase transition parameters of 4-nonyloxybenzylidene-40-alkyloxyanilines (9ꢀn)
n
Melting
Recrystallization
G
SmI
SmB
SmC
SmA
N
1
2
3
4
5
6
7
8
9
108.6 [55.40]
105.9 [52.54]
104.7 [43.20]
102.7 [40.97]
95.7 [35.74]
91.9 [35.74]
95.2 [46.27]
102.5 [45.97]
108.1 [57.75]
101.4 [52.70]
99.7 [77.19]
85.11 [50.46]
78.5 [44.71]
80.7 [40.33]
86.2 [29.18]
77.7 [26.04]
80.9 [21.87]
84.5 [31.05]
97.5 [44.53]
104.8 [57.06]
98.8 [49.70]
87.7 [59.24]
d
d
d
d
d
d
d
d
(99.0) [0.58]
118.8 [1.92]
111.5 [1.16]
115.6 [1.80]
111.4 [1.88]
115.3 [2.48]
113.5 [2.00]
115.2
d
d
d
d
d
d
d
d
d
d
d
d
d
(80.4)a
(85.2)a
d
d
d
d
d
d
d
d
d
d
(85.6)a
(93.5)
d
d
d
(87.6)a
(94.6) [0.45]
106.0 [0.86]
d
d
d
d
d
(92.3) [2.62]
(90.6) [2.10]
93.5 [2.18]
(94.0) [1.62]
(99.0)a
105.7
d
d
(78.3)a
(82.0)a
105.9 [1.30]
110.3 [1.76]
111.7 [2.50]
113.8 [8.15]b
114.1 [8.80]
114.7 [9.31]
113.0 [13.14]
10
12
d
(96.3) [3.62]
Enthalpy of the phase transition in J molꢀ1 are in square brackets and monotropic phase transition temperatures are in round brackets. d Indicates the
presence of the appropriate phases.
a
Phase transition observed only in TOA.
Inseparable peaks of enthalpy effects.
b
SmA
G
SmB
SmC
SmC
SmI
Nematic
melting
melting
Nematic
80
90
100
110
120
80
90
100
110
120
Temperature [oC ]
Temperature [oC ]
Fig. 1. DSC and TOA spectra of propyl (n = 3) derivative.
Fig. 2. DSC and TOA spectra of hexyl (n = 6) derivative.
light intensity is associated with the increase of the homeo-
tropic area. At 93.5 ꢁC the trend of light intensity reversed.
The observed minimum indicates the appearance of smectic
C phase, which was also observed as the small change of the
black homeotropic area into the color schlieren texture in
optical microscopy. DSC trace showed no anomaly in this
case. At 85.2 ꢁC in TOA another anomaly was observed.
Light intensity starts to decrease. This was reflected as a
change of the texture and the appearance of smectic B phase.
In DSC calorimetry SmA–SmB phase transition was not
observed due to the early recrystallization process. All three
mesosphases, SmA, SmC and SmB were monotropic.
As an example of the sample with rich polymorphism
the hexyl (n = 6) derivative was chosen. This compound
exhibited tetramorphism with different types of mesophases
than those observed for the propyl (n = 3) derivative. Both
DSC and TOA heating and cooling modes are shown in
Fig. 2. The heating mode exhibited three anomalies. The
melting process with a large enthalpy effect, 35.7 kJ molꢀ1
was observed at 91.9 ꢁC. There was an anomaly observed
on the right side of the melting peak. This anomaly repre-
sented a very narrow enantiotropic phase transition from
smectic I to smectic C. The repetitions of scans did not split
these two phase transitions. The estimation of the enthalpy
of SmI–SmC phase transition was not possible, even when
a very slow scanning was applied. The similar problem was
observed in the thermo-optic scan. At 110.3 and 115.3 ꢁC
two DSC peaks were observed. Both peaks were identified

262
J. Godzwon et al. / Journal of Molecular Structure 844–845 (2007) 259–267
based on the microscopic studies as SmI–SmC and SmC–N
phase transitions. Exactly the same thermal anomalies as in
DSC were observed in TOA scans. Also the phase transi-
tions in DSC and TOA measurement were observed at
the same temperatures. The temperature histeresis of
recrystalizations allows for the complete description of
SmC–SmI phase transition in the DSC and TOA cooling
scans. The enthalpy values for SmC–SmI phase transition
(Table 2) were detected in the cooling mode. In DSC exper-
iment the recrystallizaton process was observed at 83 ꢁC as
a very narrow and high peak. TOA method showed at
82 ꢁC the presence of an additional phase transition into
smectic G phase. This identification was based on the tex-
ture observations and miscibility methods.
All observed LC phases in the investigated family of
compounds are collected in Fig. 3. Isotropisation tempera-
tures for all compounds show the characteristic even–odd
effect, with significant oscillations. This behavior is typical
for derivatives with short alkyloxy chains. Nematic phase
was detected for the first eight derivatives, which contain
from methyl (n = 1) to octyl (n = 8) carbon chains. Smectic
A phase was found only for three derivatives with ethyl
(n = 2) to butyl (n = 4) chains. All derivatives from ethyl
(n = 2) exhibited smectic C phase. Most probably this mes-
ophase would also be observed in the methyl (n = 1) deriv-
ative, but its significantly high melting and freezing
temperatures excluded this possibility. Ethyl (n = 2), pro-
pyl (n = 3) and butyl (n = 4) derivatives exhibited both
smectic A and C mesophases. This behavior is unusual
for compounds with both alkyloxy chains and it can be
explained by the asymmetry of the central –CH@N– group.
The presence of smectic B mesophase in ethyl (n = 2) and
propyl (n = 3) derivatives was unexpected. Derivatives with
butyl (n = 4) and longer chains showed the presence of
smectic I mesophase, which is a tilted modification of smec-
tic B. Smectic I was not observed for nonyl (n = 9) and
decyl (n = 10) derivatives due to their high melting and
freezing temperatures. Replacement of smectic B by smec-
tic I phase confirmed the fact that derivatives with longer
alkyloxy chains tend to form tilted smectics, e.g., smectic
C and smectic I. The smectic G mesophase was observed
only in pentyl (n = 5) and hexyl (n = 6) derivatives.
Examples of LC textures are shown in Figs. 4 and 5.
Fig. 4 shows the series of textures for propyl (n = 3) deriv-
ative. A typical schlieren texture of the nematic phase is
displayed in Fig. 4a. A black triangle area in the left–lower
corner of Fig. 4a indicates a homeotropic orientation of
molecules. This texture changed with decreasing tempera-
ture into fan-shaped type texture, which is most often
found in smectic A (Fig. 4b). The orthogonal type of smec-
tics was confirmed by the homeotropic orientation of mol-
ecules, what was observed as a black area in the lower left
corner. Fig. 4c displays the change of the fan texture of
smectic A into a broken fan texture, typically observed in
smectic C phase. The black areas of homeotropically ori-
ented molecules, detected for smectic A, were replaced by
a schlieren texture, which is also very characteristic for
smectic C phase. Fig. 4d and e show typical textures of
smectic B phase. The schlieren part of a texture observed
for smectic C was replaced by homeotropic one and the
broken fan texture by the paramorphic fan shape texture.
The most important in the identification of smectic B mes-
ophase is the appearance of the perpendicular stripes in the
paramorphic fan shape pattern at phase transition temper-
ature (Fig. 4d). Fig. 4f illustrates the freezing process with
its characteristic crystal nucleus.
120
isotropic
The next series of textures (Fig. 5) show the liquid crys-
talline polymorphism of hexyl (n = 6) derivative. A typical
schlieren texture of nematic phase (Fig. 5a) changed with
the decreasing temperature into a typical texture of smectic
C (Fig. 5b). The SmC–SmI phase transition proceeded via
very characteristic sudden change of the schlieren texture
(Fig. 5c), which is also observed in nematic, smectic C
and smectic I phases. However, these phases have different
patterns. The most unique is the texture of smectic C
(Fig. 5b), which synonymously describes this mesophase.
Fig. 5d shows a polygonal texture of the smectic G meso-
phase. These last two textures required an additional
method for the proper identification of mesophases. Fur-
ther cooling of this sample showed only recrystallization
of smectic G mesophase. The formed solid state texture is
shown in Fig. 5e.
110
SmC
Nematic
melting
100
SmA
90
SmI
freezing
80
3.2. Entropic effects
G
SmB
All observed phase transitions can be quantitatively
analyzed based on their entropy values. This type of anal-
ysis was described by Demus [19] and Guillon [20]. Our
results are shown in Fig. 6. All present phase transitions
0
2
4
6
8
10
12
Alkyl chain length - n
Fig. 3. Influence of the alkyl chain length on the mesophase sequence.

J. Godzwon et al. / Journal of Molecular Structure 844–845 (2007) 259–267
263
Fig. 4. Textures of propyl (n = 3) derivative.
can be divided into three categories. The melting process
(Fig. 6a) has the highest entropy values. The entropy values
decrease from 145.1 J molꢀ1 Kꢀ1 for methyl (n = 1) deriva-
tive to the minimal value 96.9 and 98.5 J molꢀ1 Kꢀ1 for
pentyl (n = 5) and hexyl (n = 6) derivatives, followed by
increasing to 207 J molꢀ1 Kꢀ1 for dodecyl (n = 12) deriva-
tive. Even–odd tendency for derivatives with longer chains
was also observed. The parameters of the freezing process
(temperature and latent heat) depend on the experimental
conditions. When the entropy of freezing is much smaller
than the entropy of melting, the rich monotropic polymor-
phism is observed. This behavior is observed for derivatives
from butyl (n = 4) to heptyl (n = 7). The phase transitions
with the smallest entropy values are shown in Fig. 6b. The
most characteristic is Iso–N phase transition. The even–
odd effect was observed with the average values of nearly
4 J molꢀ1 Kꢀ1. This behavior was extensively investigated
in the 70-ties [21,22], but only for the nematic phase. The
entropies of N–SmA and N–SmC phase transitions do
not show even–odd effects but monotonically increase with
the alkyl chain length from 1.2 J molꢀ1 Kꢀ1 for propyl
(n = 3) derivative to 6.5 J molꢀ1 Kꢀ1 for heptyl (n = 7)
derivative. An unexpected high values of this phase transi-
tion entropy, nearly 21 J molꢀ1 Kꢀ1, was measured for
octyl (n = 8) derivative (Fig. 6c). Such a large quantitative
change of entropy value can not be explained only by the
distribution of alkyl chain conformations [23,24], especially
that the six times increase was also observed for the nonyl
(n = 9) and decyl (n = 10) derivatives, which did not exhibit
nematic mesophase. According to the thermodynamic
interpretation of the phase transition, in these cases the
entropy of the phase transitions Iso–SmC should be two

264
J. Godzwon et al. / Journal of Molecular Structure 844–845 (2007) 259–267
Fig. 5. Textures of hexyl (n = 6) derivative.
times larger than N–SmC. Also the highest value of
entropy 34 J molꢀ1 Kꢀ1 for dodecyl (n = 12) derivative
was unexpected. The entropy of the SmC–SmI phase tran-
derivatives of 9-n from ethyl (n = 2) to hexyl (n = 6) are
shown in Fig. 7.
DiagramsinFig.7aandbconfirmedthepresenceofnema-
tic, smectic A, smectic C and smectic B phases in ethyl (n = 2)
and propyl (n = 3) derivatives. Temperature of a transition
intoGmesophaseinstandard(I)dramaticallydecreasedwith
increasing concentration of the investigated derivatives. In a
nearly 0.3 molar ratio mixture of vitreous smectic B was cre-
ated, which suppressed SmB–G phase transition.
sition slightly decreased with alkyl chain length from
ꢀ1 ꢀ1
7 J mol
K
for
butyl
(n = 4)
derivative
to
4.4 J molꢀ1 Kꢀ1 for heptyl (n = 7) derivative (Fig. 6b).
An extremely high value of 9.8 J molꢀ1 Kꢀ1 was observed
for dodecyl (n = 12) derivative.
The phase diagram in Fig. 7c proved the presence of
nematic, smectic A, smectic C and smectic I mesophases
in butyl (n = 4) derivative. In addition, the induction of
the G mesophase was observed. This phase was absent in
pure components. In a 0.15 molar ratio of butyl derivative
in a mixture with standard I, smectic G disappeared.
The last two diagrams in Fig. 7d and e are the most com-
plex. The G phase showed the continuous area between stan-
dard III and pentyl (n = 5) and hexyl (n = 6) derivatives,
3.3. Phase diagrams
Three standards of mesophases were applied in the
phase diagram investigations. 4-Heptyloxybenzylidene-40-
pentylaniline (I) was used as the standard of smectic A,
smectic B and G mesophase [25], 4-hexyl-40-decyloxyazo-
benzene (II) as a standard of smectics A, C and I [26]
and 4-nonyloxybenzylidene-40-butylaniline (III) as a stan-
dard of smectics A, F and G [27]. Phase diagrams with five

J. Godzwon et al. / Journal of Molecular Structure 844–845 (2007) 259–267
265
200
175
150
melting
125
100
75
freezing
0
2
4
6
8
10
12
Alkyl chain length-n
c
b
32
28
24
20
12
8
N-SmC
N(Iso)-SmC
Iso-N
4
SmC-SmI
N-SmA
16
0
0
2
4
6
8
10
12
0
2
4
6
8
10
12
Alkyl chain length-n
Alkyl chain length-n
Fig. 6. Influence of the alkyl chain length on the effect of entropy of 4-nonyloxybenzylidene-40-alkyloxyanilines (9ꢀn).
what confirms the presence of smectic G mesophase. The
presence of nematic, smectic C and smectic I mesophases
complicated both diagrams. The change of one mesophase
into another induced additional triple points. Thus, five
types of them were observed: IsoNA, NAC, ACF, CIF and
IFG. Also hexamorphism NACIFG type was observed in
a range of contents.
hexyl (n = 6) derivatives, thrimorphism for heptyl
(n = 7) and octyl (n = 8) derivatives, dimorphism for
dodecyl (n = 12) derivative and monomorphism for
methyl (n = 1), nonyl (n = 9) and decyl (n = 10)
derivatives.
2. Unexpected orthogonal smectic B was observed for ethyl
(n = 2) and propyl (n = 3) derivatives. Smectic B was
replaced by tilted smectic I in derivatives with longer ali-
phatic chains.
4. Conclusion
3. Only pentyl (n = 5) and hexyl (n = 6) derivatives showed
the presence of G mesophase.
4. All phase diagrams confirmed the mesophase sequence
in derivatives from ethyl (n = 2) to hexyl (n = 6).
1. Rich polymorphism in 4-nonyloxybenzylidene-40-alky-
loxyaniline series was detected: tetramorphism for ethyl
(n = 2), propyl (n = 3),butyl (n = 4), pentyl (n = 5) and

266
J. Godzwon et al. / Journal of Molecular Structure 844–845 (2007) 259–267
120
110
100
90
110
isotropic phase
isotropic phase
100
90
80
70
60
50
40
Nematic
SmC
Nematic
SmC
80
SmA
SmB
SmA
SmB
70
60
50
40
G
G
30
0.0
0.0
0.2
0.4
0.6
0.8
1.0
0.2
0.4
0.6
0.8
1.0
9-3
I
9-2
I
x9-3
x9-2
120
110
100
90
c
isotropic phase
Nematic
SmC
SmI
80
SmA
70
G
freezing
60
glass
50
0.0
0.2
0.4
0.6
0.8
1.0
II
9-4
x9-4
120
e
d
110
100
90
Nematic
Nematic
110
100
90
isotropic phase
isotropic phase
•
•
TIsoNA
TIsoNA
TNAC
TNAC
•
•
SmC
SmC
SmI
SmA
SmA
TCIF
80
SmI
TACF
80
TACF
•
SmF
•
SmF
•
TCIF
•
70
•
70
•
TIFG
G
TIFG
60
60
G
0.0
0.2
0.4
0.6
0.8
1.0
0.0
0.2
0.4
0.6
0.8
1.0
III
9-6
9-5
III
x9-5
x9-6
Fig. 7. Phase diagrams ethyl (n = 2) and propyl (n = 3) derivatives with 4-heptyloxybenzylidene-40-pentylaniline, butyl (n = 4) derivative with 4-hexyl-40-
decyloxyazobenzene, pentyl (n = 5) and hexyl (n = 6) derivatives with 4-nonyloxybenzylidene-40-butylaniline.

J. Godzwon et al. / Journal of Molecular Structure 844–845 (2007) 259–267
267
[14] J. Godzwon, M.J. Sienkowska, Z. Galewski, Phase Transitions 80
(2007) 217.
Acknowledgment
[15] H. Sackmann, D. Demus, Fortschr. Chem. Forsch. 12 (1969)
349.
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1357.
This work was supported by the University of Wroclaw
Grant 2590/W/WCH.
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