A study of dendritic ionic liquid crystals: Using (S)-4-citronellyloxybenzoic acid and polypropylene imine dendrimers

Article abstract of DOI:10.1016/j.molliq.2015.12.070

In order to investigate the relationship between macromolecular structures and mesomorphic properties; dendritic ionic liquid crystals have been synthesized either by conventional method or microwave assisted synthesis technique and characterized by spectroscopic methods (FT-IR, ¹H-NMR, ¹³C-NMR). Polypropylene-imine (PPI) dendrimers based on diaminobutane (DAB) having increasing number of amino terminal groups (DABn; n = 4, 8, 16, 32) were interacted with (S)-4-citronellyloxybenzoic acid (S-CBA) which already possessed liquid crystal property. These interactions were accomplished either by sonification to obtain quaternary ammonium salt or covalently linked by using appropriate coupling reagent. The liquid crystalline properties of the dendritic molecules were investigated by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Thermal stability was studied by Thermal Gravimetric Analysis (TGA). Synthesized ion complexes showed a non-tilted smectic mesophase with wider mesomorphic range than that of single mesogenic unit, whereas those derivatives generated by covalent linkage exhibited no mesomorphism.

Full text of DOI:10.1016/j.molliq.2015.12.070

Journal of Molecular Liquids 216 (2016) 209–215
Contents lists available at ScienceDirect
Journal of Molecular Liquids
journal homepage: www.elsevier.com/locate/molliq
A study of dendritic ionic liquid crystals: Using
(S)-4-citronellyloxybenzoic acid and polypropylene imine dendrimers
Harun Nezih Türkçü a,b, Hale Ocak a, Mustafa U. Gürbüz a, Fatih Çakar a, Belkiz Bilgin-Eran a, Metin Tülü a,
⁎
a
Yıldız Technical University, Faculty of Arts and Sciences, Dept. of Chemistry, 34220 Istanbul, Turkey
b
TUBITAK Marmara Research Center, Environment and Cleaner Production Institute, 41470 Kocaeli, Turkey
a r t i c l e i n f o
a b s t r a c t
Article history:
In order to investigate the relationship between macromolecular structures and mesomorphic properties; den-
dritic ionic liquid crystals have been synthesized either by conventional method or microwave assisted synthesis
technique and characterized by spectroscopic methods (FT-IR, 1H-NMR, 13C-NMR). Polypropylene-imine (PPI)
dendrimers based on diaminobutane (DAB) having increasing number of amino terminal groups (DABn; n =
4, 8, 16, 32) were interacted with (S)-4-citronellyloxybenzoic acid (S-CBA) which already possessed liquid crystal
property. These interactions were accomplished either by sonification to obtain quaternary ammonium salt or
covalently linked by using appropriate coupling reagent. The liquid crystalline properties of the dendritic mole-
cules were investigated by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM).
Thermal stability was studied by Thermal Gravimetric Analysis (TGA). Synthesized ion complexes showed a
non-tilted smectic mesophase with wider mesomorphic range than that of single mesogenic unit, whereas
those derivatives generated by covalent linkage exhibited no mesomorphism.
Received 25 August 2015
Accepted 19 December 2015
Available online xxxx
Keywords:
Liquid crystalline dendrimer
PPI
Smectic mesophase
© 2015 Elsevier B.V. All rights reserved.
1. Introduction
One advantage of ionic liquid crystal dendrimers, as compared to
their covalent homologues which are obtained by the introduction of
Dendrimers; due to their monodispersity, bearing high density of
peripheral functional group and consequent advantage of modulating
these functional groups make them highly attractive macromolecules
for different kinds of applications [1–9]. Recent studies on liquid crystals
that are associated with dendrimers have made significant contribution
to the subject of Thermotropic Liquid Crystals [10–13].
LCDs utilize typical characteristic properties of dendrimers at core of
macrostructure and exquisite choosing rod-like or disc-like mesogenic
units or building blocks at periphery. LCDs have been synthesized by co-
valent bonding [14–16] of mesogenic units or electrostatic interaction
[17–19] of mesogenic groups with dendrimers.
The ionic liquid crystal dendrimers are obtained by electrostatic in-
teraction between the terminal units of mesogenic groups and the flex-
ible dendritic network. It is remarkable from some studies [20–23] that
the ionic interactions are useful to design liquid crystalline systems. The
chemical incompatibility between the flexible dendritic core and the
terminal chains, the size of the dendrimer as well as the structure of
the mesogenic unit play a crucial role in the formation of a thermotropic
mesophase and stabilization of ionic-type liquid crystals.
mesogenic unit to the branch of dendrimer, is the easy preparation of
many kinds of dendrimer systems with liquid crystalline properties.
Due to the fact that ionic interactions within these systems have a
pronounced effect on the emergence of liquid crystalline phases, the
formation of ion pairs between alkoxy benzoic acids and the terminal
amine groups has been used in some studies [20–21] as a route to in-
duce a smectic mesomorphism which the molecules ordered parallel
to each other. Columnar phase [22–23] which the molecules organized
within columns has been observed for this kind of materials depending
on the structure of mesogenic unit.
In this study, the synthesis and characterization of ionic liquid crystal
dendrimers which are composed of a (S)-4-citronellyloxybenzoic acid
[24] (S-CBA) mesogenic unit exhibiting a narrow mesomorphic range
and polypropylene-imine dendrimers (DABn) have been reported. In
the study of ammonium salts (DABn & S-CBA), the number of terminal
amine groups of dendrimers is indicated by n. Ionic complexation with
substituted benzoic acid has been carried out by using four generations
(n = 4, 8, 16, 32) of polypropylene-imine dendrimers.
Additionally, S-CBA mesogenic unit was covalently introduced to pe-
riphery of DAB16 and DAB32 dendrimers by using DCC coupling reac-
tion in order to investigate the difference in the mesomorphism which
results from ionic or covalent bonding. The structures of all materials
were characterized by using FT-IR, 1H-NMR and 13C-NMR spectroscopic
methods. The mesomorphic properties were investigated by POM and
DSC. In addition, thermal stability was investigated by TGA.
⁎
Corresponding author.
E-mail addresses: hnturkcu@gmail.com (H.N. Türkçü), hale_ocak@yahoo.com
(H. Ocak), mustafaulvig@gmail.com (M.U. Gürbüz), ffatihcc@yahoo.com (F. Çakar),
bilgineran@yahoo.de (B. Bilgin-Eran), tulumetin@gmail.com (M. Tülü).
http://dx.doi.org/10.1016/j.molliq.2015.12.070
0167-7322/© 2015 Elsevier B.V. All rights reserved.

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H.N. Türkçü et al. / Journal of Molecular Liquids 216 (2016) 209–215
prepared from the commercially available (S)-(−)-β-citronellol by
tosylation as described in literature [28].
After the etherification reaction of ethyl 4-hydroxybenzoate with
the (S)-citronellytosylate, the hydrolysis was realized to obtain 4-((S)-
citronellyloxy)benzoic acid [24]. Sodium hydroxide (50 mmol) was dis-
solved in ethanol (35 ml, 95%) and then the yellow liquid (25 mmol)
was added to this solution. The reaction mixture was refluxed for 3 h.
The completion of the reaction was monitored by TLC (CHCl3). The mix-
ture was poured into 35 ml water and then the aqueous solution was
acidified to pH 1 by adding 1 N HCl. The obtained precipitate was fil-
tered, washed with water and purified by crystallization from ethanol.
Yield: 87%; colorless crystals. 1H-NMR (400 MHz, CDCl3): δ = 8.03 (d,
J ≈ 8.9 Hz; 2 Ar-H), 6.92 (d, J ≈ 8.9 Hz; 2 Ar-H), 5.09 (t, J ≈ 7.2 Hz;
1H, CH_C(CH3)2), 4.09–4.00 (m; 2H, OCH2), 2.04–1.94 (m; 2H,
CH2\\CH_C(CH3)2), 1.89–1.79 (m; 1H, CH), 1.75–1.54 (m; 8H, CH2, 2
CH3), 1.43 1.17 (m; 2H, CH2CH2CH_C(CH3)2), 0.95 (d, J ≈ 6.4 Hz; 3H,
CH3).
Scheme 1. Diaminobutane based (DAB) polypropylene imine dendrimer with 8 terminal
amino groups (DAB8)
2. Experimental
2.1. Materials
2.3.2. Ionic synthesis
As shown in Scheme 2, S-CBA mesogenic unit with a carboxyl group
was added into second generation amine terminated dendrimer
(Scheme 1) with respect to one to one stoichiometric rate for each ter-
minal group of dendrimer. The ionic moiety was sonicated in dry THF
for 15 min by heating until observing a transparent solution. Then, the
solvent was removed in vacuo. (See Scheme 2.)
DAB4, DAB8, DAB16 and DAB32 polypropylene-imine dendrimers
were purchased from SyMO-Chem and used without further purifica-
tion. Dry THF as a solvent was used in the synthesis of both ammonium
salts DABn & S-CBA and covalent dendrimers DAB-(S-CBA)n.
2.2. Techniques
2.3.3. Covalent synthesis
The characterization of the materials is based on 1H-NMR and 13C-
NMR (Bruker Avance III 500 MHz) spectrometer, in CDCl3 solutions,
with tetramethylsilane as internal standard), FT-IR/ATR (Perkin-Elmer
spectrophotometer). Transition temperatures were measured using a
Mettler FP-82 HT hot stage and control unit in conjunction with a
Leica polarizing microscope. DSC-thermograms were recorded on a
Perkin-Elmer Pyris 6, heating and cooling rate: 10 °C/min. TGA studies
were performed using Exstar SII TG/DTA 7200.
The carboxylic acid group of S-CBA is coupled with amine groups of
DAB16 and DAB32 in the presence of N,N′-dicyclohexylcarbodiimide
and 1-hydroxybenzotriazole (DCC & 1-HOBt) as shown in Scheme 3.
2.3.4. Synthesis of DAB-(S-CBA)32
The mixture of 1.268 mmol of S-CBA, N,N′-dicyclohexycarbodiimide
(DCC) and 1-hydroxybenzatriazole (1-HOBt) was stirred at room tem-
perature in dry THF under a nitrogen atmosphere for 1 h. Then, 5 ml
THF solution containing 0.0342 mmol of the corresponding DABn in
THF was gradually added into this mixture. The mixture was stirred
for two days at room temperature. The reaction mixture was filtered
off and washed with THF. After removing the solvent in vacuo, the
resulting product was extracted three times with chloroform. Organic
phase was dried with Na2SO4 and volatile components were removed
in vacuo. The crude product was purified by dialysis having 3 kD pore
size in ethanol. The purity of the target dendrimers was checked out
by TLC and disappearance of primary amine and appearance of amide
by ATR.
2.3. Synthesis
2.3.1. Synthesis of (S)-4-citronellyloxybenzoic acid
The synthesis of S-CBA liquid crystal [24] was carried out according
to procedures described in the literature [25–26]. Firstly, the mixture
of ethyl 4-hydroxybenzoate (30 mmol), (S)-citronellol tosylate
(45 mmol) and K2CO3 (45 mmol) in DMF (120 ml) was refluxed
under argon atmosphere for 5 h, and the end of the reaction was mon-
itored by TLC (hexane:ethyl acetate/5:1). The resulting mixture was fil-
tered on silica gel and washed with CHCl3. The volatile components
were removed in vacuo and the light yellow viscous liquid was obtained
after the purification by column chromatography on silica gel eluting
with hexane:ethyl acetate/20:1. (S)-Citronellol tosylate [27] was
DAB-(S-CBA)32: Yield: 0.36 g (89%) of dark orange solid. IR (ATR):
3318 cm−1 (N\\H), 1631 cm−1, 1545 cm−1 (amide I and amide II).
1H-NMR (400 MHz, CDCl3) δ ppm: 7.9 (32H, NH), 7.7 (64H, Ar\\H),
6.7 (64H, Ar\\H), 5.0 (32H, C_CH), 3.9 (64H, OCH2). 13C-NMR
Scheme 2. Demonstration of ionic complexation between S-CBA mesogenic unit and diaminobutane (DAB) based polypropylene-imine (PPI) dendrimers DABn (n = 4, 8, 16, 32).

H.N. Türkçü et al. / Journal of Molecular Liquids 216 (2016) 209–215
211
Scheme 3. Representation of amidation reaction between S-CBA and diaminobutane (DAB) based polypropylene-imine (PPI) dendrimers DABn (n = 16 and 32).
(100 MHz, CDCl3) δ ppm: 167.4 (O_CNH); 161.6, 129.1, 126.6, 114.0
(aromatic C); 131.3, 124.6 (olefinic C); 66.4 (OCH2).
of alkoxy group shifts from 163.70 ppm to 161.17 ppm (around
−2.53 ppm) in case of ionic form due to increase of electron density
on this carbon (see Fig. 2). In contrast to this change in chemical shift,
carbonyl carbon (C_O) shifts [19,30] from 172.37 ppm to 173.26 ppm
(around +0.89 ppm) due to decrease of electron density. It means
that chemical shift distance between carbonyl peak and aromatic car-
bon peak increases from 8.67 ppm to 12.09 ppm. The change in chemi-
cal shifts which was observed in DAB4 & S-CBA was similarly detected
for ionic dendrimers composed of DAB8, DAB16 and DAB32.
DAB-(S-CBA)16: Similar procedure and same purification steps were
applied. Dark orange solid substance was obtained. IR (ATR):
3332 cm−1 (N\\H), 1633 cm−1, 1564 cm−1 (amide I and amide II).
1H-NMR (400 MHz, CDCl3) δ ppm: 8.0 (16H, NH), 7.8 (32H, Ar\\H),
6.8 (32H, Ar\\H), 5.1 (16H, C_CH), 3.9 (32H, OCH2). 13C-NMR
(100 MHz, CDCl3) δ ppm: 167.8 (O_CNH); 161.7, 129.2, 126.0, 114.1
(aromatic C); 131.2, 124.6 (olefinic C); 66.4 (OCH2).
1H-NMR spectra which are given in Fig. 3 show that broad peaks are
observed at 7.6 ppm, 7.0 ppm, 6.6 ppm and 6.6 ppm corresponding to
NH+3 formation for DAB4 & S-CBA, DAB8 & S-CBA, DAB16 & S-CBA and
DAB32 & S-CBA salts, respectively. The signals corresponding to the ar-
omatic protons of alkoxy benzoate unit shift from 8.06 ppm and
6.93 ppm to 7.89 ppm and 6.70 ppm, respectively due to increase in
electron density of aromatic ring. Similarly, the signals of oxymethylene
protons of S-CBA in ion complex shift to higher field (3.85 ppm) as com-
pared with the signals of pure S-CBA at 4.04 ppm. Additionally, the sig-
nals of methylene protons which are next to amino group (\\CH2NH2)
which were observed at 2.63 ppm for the dendrimer shift to 2.88 ppm
(\\CH2NH+3 ) in ionic dendrimer. This change in chemical shift indicates
the protonation of primary amines [23,29]. The protonation of tertiary
amino groups is detected by the observation of minor signal at
2.65 ppm [23,29] for DAB-8 & S-CBA and 2.55 ppm for DAB8 & S-CBA,
3. Results and discussion
The formation of ionic interaction between the amino groups of
dendrimers and a carboxyl group of the mesogenic unit was mainly
checked out by FT-IR. While a sharp peak belonging to the carboxylic
acid about 1670 cm−1 disappeared, symmetric stretching vibration be-
longing to carboxylate groups at 1380 cm−1 is distinctively observed
(see Fig. 1). Moreover, asymmetric stretching carboxylate peak at
1550 cm−1 is also detected. In addition, while the broad N\\H+
stretching vibration is observed at 2670 cm−1, peaks at 3335 and
3285 cm−1 belonging to NH2 group in neat dendrimer disappeared.
NMR spectroscopy is another significant method to reveal the pro-
tonation of the amino groups of dendrimers by a change in chemical
shifts. 13C-NMR spectra show that Ar\\C atom which is next to oxygen
Fig. 1. FT-IR spectra of DAB4, S-CBA and DAB4 & S-CBA salt.

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H.N. Türkçü et al. / Journal of Molecular Liquids 216 (2016) 209–215
Fig. 2. 13C-NMR spectra (in CDCl3) of S-CBA and DAB4 & S-CBA ammonium salt.
DAB16 & S-CBA, and DAB32 & S-CBA. In 1H-NMR spectra of DAB4 & S-
CBA, no signal corresponding to the protonation of tertiary amino
groups was observed. The multiplet signals at 5.09 ppm of olefinic pro-
tons in alkoxy chain show no shifting by ionic complexation due to the
fact that their electronic environment did not change.
The mesomorphic properties of ionic macromolecules DABn & S-
CBA and covalent dendrimers DAB-(S-CBA)n were investigated by po-
larized light optical microscopy (PM) and differential scanning calorim-
etry (DSC).
The transition temperatures, corresponding enthalpy values and
mesophase type observed for S-CBA and ionic macromolecules are sum-
marized in Table 1.
As shown in Table 1, ionic macromolecules DABn & S-CBA (n = 4, 8,
16, 32) exhibit smectic A mesophase. On cooling from the isotropic liq-
uid of ionic macromolecules DABn & S-CBA (n = 4, 8, 16), a fan-shaped
texture in planar alignment or an optically isotropic region in
homeotropic alignment appears at 164–161 °C, as typical for non-
tilted smectic (SmA) phase (see Fig. 4a–d). The transition from the
isotropic liquid state to smectic A phase is indicated in the DSC heating
and cooling scans by transition enthalpy values between 4.7 and 3.0 J/g.
As previously reported [17–21,23,29], the formation of SmA mesophase
is explained by ionic interaction between carboxyl group and terminal
amine groups of the PPI dendrimer. In this non-covalent intermolecular
interaction between the functional group (\\NH2) at the surface of the
DABn and COOH group of mesogenic compound S-CBA, the \\NH2
group of the DABn acts as a proton acceptor and COOH of S-CBA with
(S)-citronellyloxy terminal chain as the proton donor. In resultant
ionic dendrimers, the ionic interaction has a striking influence on phys-
ical properties such as melting and clearing temperatures, enthalpies,
inducing new phase with wide thermal range, and stabilizing the liquid
Fig. 3. The comparison of 1H-NMR spectra (in CDCl3) of DAB4, S-CBA, DAB4 & S-CBA, DAB8 & S-CBA, DAB16 & S-CBA, and DAB 32 & S-CBA salts.

H.N. Türkçü et al. / Journal of Molecular Liquids 216 (2016) 209–215
213
Table 1
Mesophases, phase transition temperatures and transition enthalpies of the S-
CBA and ionic macromoleculesa.
Sample
T/°C [ΔH J/g]
2nd heating process
S-CBA
Cr 76 [54.4] SmC* 83 [2.5] Iso
Cr 29 [3.3] SmA 164 [4.7] Iso
Cr 32 [3.0] SmA 163 [3.2] Iso
Cr 36 [1.9] SmA 161 [3.0] Iso
Cr 36 [0.9] SmA 143 [1.0] Iso
DAB4&S-CBA
DAB8&S-CBA
DAB16&S-CBA
DAB32&S-CBA
a
Perkin-Elmer Pyris 6 DSC; heating and cooling rate: 10 °C/min; enthalpy
values are given behind the phase transition temperatures in square parenthe-
ses; abbreviations: Cr = crystal, SmA = smectic A mesophase and Iso =
isotropic liquid phase.
crystalline phase. In these dendrimer systems DABn& S-CBA (n = 4, 8,
16, 32), the incompatibility between aliphatic and aromatic building
Fig. 5. First cooling cycle of DSC thermograms of S-CBA, DAB4 & S-CBA, DAB8 & S-CBA,
DAB16 & S-CBA, and DAB32 & S-CBA salts.
blocks of mesogenic unit S-CBA, ionic blocks (\\NH3+
…
−OOC\\) and
dendrimeric part induces micro-segregation. As a result of the molecu-
lar organization which is composed of these distinct incompatible seg-
ments, a lamellar SmA mesophase is observed in ionic dendrimers
DABn & S-CBA (n = 4, 8, 16, 32). In most examples of liquid crystal
dendrimers exhibiting lamellar phases, the smectic behavior is ex-
plained by a model in which the dendrimeric supermolecule adopts a
cylindrical conformation. The cylinders are arranged parallel to each
other giving rise to lamellar phase [12].
In contrast to DABn & S-CBA (n = 4, 8, 16), the highest generation of
PPI dendrimer (DAB32 & S-CBA) has a lower clearing point and transi-
tion enthalpy value (1.0 J/g). This change indicates that highly
branching of dendrimers plays a key role on the decreasing in transition
temperatures of mesophase. and no peak or distinct step is also ob-
served in the cooling DSC curves (see Fig. 5). According to the POM
Fig. 4. Polarized light optical photomicrographs of the smectic A mesophases for the four generation of ionic dendrimers on cooling; (a) the texture of DAB4 & S-CBA after shearing at 126 °C
in the homeotropically aligned sample; (b) the fan-shaped texture of DAB8 & S-CBA at 80 °C; (c) the texture of DAB16 & S-CBA at 140 °C; (d) the fan-shaped texture of DAB32 & S-CBA at
120 °C (magnification ×100).

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H.N. Türkçü et al. / Journal of Molecular Liquids 216 (2016) 209–215
and characterized. In order to investigate the effect of the binding type
(ionic or covalent) of mesogenic unit on the mesomorphism of these ma-
terials, their covalent analogues DAB-(S-CBA)16 and DAB-(S-CBA)32 were
also obtained by the introduction of the same mesogenic unit to the
branch of dendrimer. Ionic dendrimers exhibit smectic A phase with
wide temperature range whereas covalent dendrimers have no
mesomorphism. The micro-segregation of incompatible structural units
influences the mesophase morphology and ionic interactions also con-
tribute to the mesophase stabilization in the systems discussed here.
The flexible structure of ionic dendrimers offers advantages for
mesophase formation compared to rigid covalent bond based dendritic
system. Due to the most probably steric hindrance effect depending on
the congestion of surface amino groups in the PPI dendrimer, the increase
in the generation number of ionic dendrimers gives rise to a relative de-
crease in clearing temperatures.
Fig. 6. Second heating cycle of DSC thermograms of S-CBA, DAB4& S-CBA, DAB8 & S-CBA,
DAB16 & S-CBA, and DAB32 & S-CBA salts.
Acknowledgment
This research has been supported by Yıldız Technical University Sci-
entific Research Projects Coordination Department, project number:
2013-01-02-DOP02. The authors gratefully acknowledge Dr. Ayfer
Sarac and Dr. Cemil Dizman for providing TGA and NMR opportunities,
respectively.
observations, the obtained ionic macromolecules show very slow crys-
tallization on the cooling process and as a result of this, none of ionic
dendrimers show a crystallization peak on cooling to room temperature
in DSC. The similar observation was reported in the literature [21] for
PPI based ionic polymers. In the heating curves, a broad peak with
small enthalpy, which corresponds to solid–liquid crystal transition, at
around 25–40 °C was clearly observed for each ionic macromolecule
DABn & S-CBA (n = 4, 8, 16, 32) (see Fig. 6).
In contrast to mesogenic (S)-4-citronellyloxybenzoic acid (S-CBA)
which exhibits SmC* mesophase with nearly 7 °C temperature range,
dendritic ionic molecules significantly have a wider mesophase range.
It seems that the ionic interaction has a stabilizing effect on the
mesophase. Another point is that the clearing points of DABn & S-CBA
ionic molecules decrease with increasing the generation number of
dendrimers, as observed in previous report [31]. Additionally, there is
a minor increase on melting points.
In contrast to dendritic ionic molecules, the introduction of S-CBA
into the periphery of dendrimer by covalent bonding gives rise to
non-mesomorphic materials DAB-(S-CBA)16 and DAB-(S-CBA)32. It can
be explained by relatively rigid structure in covalently bonded com-
pared to flexible ionic bonding architecture. These results were correlat-
ed with the literature either in electrostatic interaction of LC group with
dendrimer [29] or LC group linked covalently to the dendritic core [32].
Thermal stability of ammonium salts under nitrogen was investigat-
ed by TGA (heating rate: 5 °C/min) (see Table 2). Ionic system is consid-
erably stable until 170 °C, above isotropic point. Until 200 °C, weight loss
due to oxidation or other chemical transformations can be acceptable.
However, there is a serious chemical decomposition between 200 °C
and 300 °C. Decomposition rate seems independent of dendrimer
generations.
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Table 2
The percentage of weight loss obtained from TGA studies of the ionic systems.
Sample
(%) Weight loss at (%) Weight loss at (%) Weight loss at
170 °C
200 °C
300 °C
DAB4 & S-CBA salt
DAB8 & S-CBA salt
DAB16 & S-CBA salt 8.3
DAB32 & S-CBA salt 4.5
4.5
7.4
6.3
9.0
10.4
6.0
74.5
74.5
73.2
77.7

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