Synthesis and characterization of novel jacketed polymers and investigation of their self assembly and application

Chapter 2
Part1
Synthesis and characterization of novel jacketed
polymers













32

2.1.1 Introduction
The development of synthetic materials with controlled nanostructures is a fascinating
area of scientific research in science and engineering. The driving forces arise from
areas such as biological, microelectronic material science and development of

sensing, actuating, and control devices with components in the nano- or microscale
1
.
Various chemical synthesis and physical manipulation techniques are under
development to meet the challenge of architectural control in nanoscale. Examples
include electrodepositing metals inside the pores of commercial membrane, growing
polymers in the cavities of inorganic clay and sieves
2-3
, or self-assembly methods to
develop nanostructured materials.
Self-assembly of molecules through non-covalent forces including hydrophobic and
hydrophilic effects, electrostatic interactions, hydrogen bonding, microphase
segregation, and shape of molecules have significant potential for creating such
supramolecular structures
4-5
. It is relatively easy to self-assemble macromolecules
into ordered morphologies covering several length-scales
6
.
There is growing interest in the precise control of the order of macromolecules in the
nano-scale through self-assembly, which may be used in improvement of the material
properties, lithographic techniques, chemical sensors and so on. The order of
macromolecules depends largely on the primary structure and the segmental
interaction of polymers. It is well known that the chain stiffness of polymers offers a
method of controlling the spatial arrangement of a polymer chain. This stiffness may
contribute to the formation of supramolecular structures and is used to demonstrate
the correlation between chemical structure and performance in application. There are
usually two ways to make the chain stiff. In one method, the main chain of the

33

polymer is made of rigid, interconnected groups. For example, many rigid - coil block
copolymers with helical rods, mesogenic rods, and conjugated rods, have been
reported
7
. Another way is to force the main chain to take a rigid conformation through
the attachment of many side groups on the polymer backbone. These polymers can be
considered as jacketed polymers and used as building blocks can provide valid access
to the construction of interesting architectures
5-9
.
The concept of jacketed polymers was first proposed by Zhou et al.
9-11
to describe a
new type of liquid crystalline polymers in which the mesogenic units were attached
laterally to the main chain via a direct connection or via short spacers. The results of
X-ray diffraction
9
revealed that the rigid side groups spiral around the backbone of the
mesogen - jacketed polymers and the morphological study showed that the polymers
have a branded texture similar to that of the semi - rigid main - chain liquid crystalline
polymers. The authors suggested that the jacketed polymer’s main chain backbone
was forced to take a stiffen conformation due to the steric repulsion between the
densely grafted side chains and excluded volume effects. These jacketed polymers
often show liquid crystalline properties and allow the creation of highly ordered
architecture.
Polymacromonomers can also be considered as a kind of jacketed polymers, in which
the side group is a flexible polymer chain. Schmidt’s group
12
reported the synthesis of
polymacromonomers based on polystyrene side chains and a methacrylate main chain.

Such polymers adopt the conformation of a cylindrical brush. The study showed that
the methacrylate main chain exhibits extremely high chain stiffness in the order of
100 nm for the Kuhn statistical segment length, and it depends on the length of the
side chains used.


34
Percec et al. synthesized a series of monodendron - jacketed polymers
5, 7, 8, 13-15
. They
demonstrated a rational control of polymer conformation through self-assembly of
monodendritic side - groups. At low degree of polymerization (DP), the conical
monodendrons assembled to produce a spherical polymer with random - coil
backbone conformation. At high DP, the monodendritic units changed to give a
cylindrical polymer with an extended backbone. This correlation between polymer
conformation and DP is opposite to that seen in most synthetic and natural
macromolecules. This may provide a new method for the design of organized
supramolecular materials for nanotechnology, functional films and fibers, and
molecular devices.
The Schluter group
16
have reported the synthesis of poly(p-phenylene) substituted
with monodendron side groups, in which the main chain is rigid and of sterically
crowded. The scanning tunneling microscopy (STM) investigations showed that the
polymers take rigid rod type conformation.
Recent years have seen much progress in the use of rigid components in polymers as
building blocks to form interesting supramolecular structures and their intriguing
properties are extensively discussed
9,10,13
. Generally, the rigid components are

incorporated on the main chain of the polymers. Further studies are required to
understand the properties of jacketed polymers in which the main chain is sterically
crowded with laterally attached rigid side chains
17-19
.
Here we report the synthesis of a series of novel jacketed polymers. Constitutes on the
polymer backbone are designed to incorporate strong electrostatic, weak Van der
Waals interactions, and shape effects, to control the self-assembly of polymer chains
in the lattice. The novel polymers were characterized with GPC, DSC, TGA, FTIR,

35
and NMR. This work show characterization about the rigid side chain organization
and provide a new method to design novel macromolecular building blocks.

2.1.2 Experimental section
2.1.2.1 Materials and reagents
All reagents and solvents were obtained from commercial supplies and used without
further purification unless noted otherwise. Tetrahydrofuran (THF) was distilled over
sodium and benzophenone under N
2
atmosphere. N, N-dimethylformamide(DMF)
was dried with 4 Å molecular sieves (Aldrich). Flash column chromatography was
performed using silica gel (60-120 mesh, Aldrich).
2.1.2.2 Instrumentation
Fourier transform infrared (FT-IR) spectra were obtained using a Perkin-Elmer 1616
FT-IR spectrometer as KBr mulls.
1
H NMR,
13
C NMR spectra were recorded on a

Bruker ACF 300 MHz spectrometer. Thermogravimetric analyses (TGA) and
differential scanning calorimetry (DSC) traces were recorded using a TA-SDT2960
and a TA-DSC 2920 at a heating rate of 10 °C min
-1
under N
2
environment. The XRD
patterns were recorded on an X-ray powder diffractometer with a graphite
monochromator using Cu-Kα radiation with a wavelength of 1.54 Å at room
temperature (scanning rate: 0.05
o
/s; scan range 1.5-30
o
). Gel permeation
chromatographic (GPC) analyses were conducted with a Waters 2696 separation
module equipped with a Water 410 differential refractometer HPLC system and
Waters Styragel HR 4E columns using THF as eluent and polystyrene as standard.
Melting points (Mp) were obtained on a BÜCHI Melting Point B-540 apparatus and
are uncorrected.


36

2.1.2.3 Synthesis.
Poly(5’-dodecyloxy-[1, 1’; 4’, 1’’]terphenyl-2’-yl methacrylate) (7a), poly(5’’-
dodecyloxy [1, 4’; 1’, 1’’; 4’’, 1’’’; 4’’’, 1’’’’] quinquephenyl-2’’-yl methacrylate )
(7b), poly(1, 3-bis (5'-dodecyloxy [1, 1'; 4', 1''] terphenyl-2'-yloxy) propan-2-yl
methacrylate) (10a) and poly (1, 3-bis (5''-dodecyloxy [1, 4'; 1', 1''; 4'', 1'''; 4''', 1'''']
quinquephenyl-2''-yloxy) propan-2-yl methacrylate) (10b)
were synthesized using the

following route shown in Scheme 2.1.1:

Synthesis of monomers and polymers

2,5-dibromohydroquinone (1)
In a 1L round-bottom flask containing a teflon stir bar was placed 110.2 g
hydroquinone (1 mol) and 200 ml glacial acetic acid. A solution of 102.7 ml Br
2
(0.99
mol) in 150 ml glacial acetic acid was added dropwise to the flask. After finish the
addition, the reaction mixture was kept stirring at RT for 12 h, then poured into water.
The precipitate was recrystallized in glacial acetic acid to yield a white crystalline
solid. Yield: 189.4g (71 %).
1
H NMR (300MHz, DMSO-d
6
, δ ppm): 7.16 (s, Ar-H, 2
H), 5.16 (s, Ar-OH, 2 H).




37
B(OH)
2
OBn
C
12
H
25

O
OBn
C
12
H
25
OH
C
12
H
25
O
OH
C
12
H
25
O
H
2
B(OH)
2
H
2
ROH
H
2
CC
CH
3

C O
RO
H
2
CC
CH
3
C O
RO
AIBN
H
2
CC
CH
3
C O
O
OR OR
OH
OR OR
OH
Br Br
ROH
H
2
CC
CH
3
C O
Cl

H
2
C
C
CH
3
C O
O
OR OR
H
2
CC
CH
3
C O
Cl
AIBN
3
Pd(PPh
3
)
4
\toluene\Na
2
CO
3
Pd/C
4b
5b
n

R=
n
6
7
8
10
9
a
b
5
5
TEA/THF
TEA/THF
DMF/K
2
CO
3
3
Pd(PPh
3
)
4
\toluene\Na
2
CO
3
Pd/C
4a
5a
OH

OH
Br
2
OH
OH
Br
Br
OBn
OC
12
H
25
Br
Br
OH
OC
12
H
25
Br
Br
Glacid acetic acid
NaOH/Ethanol
12-bromoldodecane
K
2
CO
3
/Ethanol
Benzylbromide

1
2
3
C
12
H
25
O
C
12
H
25
O


Scheme 2.1.1: Synthesis route for the monomers and polymers

38
2,5-dibromo-4-dodecyloxyphenol (2)
53.6 g of compound 1 (0.2 mol), 12 g NaOH (0.3 mol) and 500 ml absolute ethanol
were added to a 1 L round-bottom flask, purged with N
2
for 20 min, heated to 50-60
°C under N
2
atmosphere and 46 ml bromododecane (0.19 mol) was added dropwise to
the solution. After finishing the addition, the reaction mixture was stirred for 18 h.
The reaction mixture was allowed to cool to RT and then filtered. The solution was
concentrated and poured into dilute HCl. The precipitate was recrystallized in hexane
to yield a white powder. Yield: 26.9 g (32.5 %).

1
H NMR (300 MHz, CDCl
3
, δ ppm):
7.24 (s, Ar-H, 1 H), 6.90 (s, Ar-H, 1 H), 5.15 (s, Ar-OH, 1 H), 3.93 (t, J = 6.4 Hz,
ArO-CH
2
-, 2 H), 1.80 (p, J = 6.8 Hz, R(O)-CH
2
-,2 H), 1.27 (b, -CH
2
-, 18 H), 0.8 (t, J
= 6.0 Hz, -CH
3
, 3 H).
13
C NMR (75.4 MHz, CDCl
3
, δ ppm): 150.0, 120.2, 118.4,
116.2, 112.5, 108 (ArC), 70.3 (O-C-), 31.8, 29.6, 29.5, 29.4, 29.2,29.1, 28.9, 23.4,
22.6, 13.9 (-CH
2
-), 11.3 (-CH
3
). MS (EI): m/z: 438.2, 436.2. Mp:66 °C.
1-benzyloxy-2, 5-dibromo-4-dodecyloxy benzene (3)
In a 1L round-bottom flask was placed 21.8 g compound 2 (0.05 mol), 10.4 g K
2
CO
3

(0.075 mol) and 400 ml absolute ethanol. The mixture was purged with N
2
for 20 min,
heated to 75°C under the atmosphere of nitrogen. A solution of benzyl bromide 11.9
ml (0.1 mol) in 50 ml absolute ethanol was added dropwise. After finishing the
addition, the reaction mixture was kept stirring for 18 h, cooled to RT and filtered.
The solution was concentrated and poured into water. The precipitate was
recrystallized in ethanol to yield a white powder. Yield: 20.5 g (77.9 %).
1
H NMR
(300 MHz, CDCl
3
, δ ppm): 7.47 - 7.32 (m, Ar-H, 5 H), 7.16 (s, Ar-H, 1 H), 7.11 (s,
Ar-H, 1 H), 5.07 (s, ArO-CH
2
-, 2 H), 3.95 (t, J = 6.6 Hz, ArO-CH
2
-, 2 H), 1.83 (q, J =
6.8 Hz, 2H), 1.27 (b, -CH
2
-, 18 H), 0.89 (t, J = 6.0 Hz, -CH
3
, 3H).
13
C NMR (75.4
MHz, CDCl
3
, δ ppm): 150.5, 149.5, 136.2, 128.5, 128.0, 127.2, 119.3, 118.2, 111.5,

39

111.0 (ArC), 72.0, 70.1 (O-CH-), 32.8, 29.6, 29.4, 29.3, 29.2, 29.0, 25.8, 22.6, 14.0 (-
CH
2
-), 11.3 (-CH
3
). MS (EI): m/z: 526.1, 524.2. Mp: 152 °C.
2’-Benzyloxy-5’-dodecyloxy [1, 1’; 4’, 1’’] terphenyl (4a)
20

A 500 ml round-bottomed flask equipped with a condenser was charged with 10.52 g
compound 3 (20 mmol), 7.32 g phenyl boronic acid (60 mmol), 80 ml toluene, 20 ml
methanol and 100 ml 2M sodium carbonate solution. The mixture was degassed
before the catalyst tetrakis(triphenylphosphine) palladium (1 g, 5 mol%) was added in
dark under argon atmosphere. The reaction mixture was heated to 100 °C for 48 h,
cooled to RT and filtered. The liquid layer was separated with a separation funnel, and
the aqueous layer was extracted with toluene (100 ml × 2). The toluene layer was
combined and washed with 3× 100 ml water and dried over MgSO
4
. The solvent was
then removed under reduced pressure, and the resulting crude product was purified
using column chromatography on silica gel column with hexane and dichloromethane
(4:1) as the eluant. Yield: 4.6g (44.3%).
1
H NMR (300 MHz, CDCl
3
, δ ppm): 7.65 -
7.29 (m, ArH, 15 H), 7.06 (s, Ar-H, 1 H), 7.00 (s, Ar-H, 1 H), 4.99 (s, ArO-CH
2
-,
2H), 3.92 (t, J = 6.5 Hz, ArO-CH

2
-, 2 H), 1.68 (p, J = 6.5 Hz, R(O)-CH
2
-, 2 H), 1.26
(b, -CH
2
-, 18 H), 0.8 (t, J = 6.3 Hz, 3 H).
13
C NMR (75.4 MHz, CDCl
3
, δ ppm): 150.7,
149.7, 149.5, 148.3, 148.2, 148.1, 138.3, 138.2, 131.4, 130.7, 129.5, 129.4, 128.3,
127.9, 127.8, 127.5, 127.3, 127.3, 127.1, 126.9, 126.8, 117.4, 116.1 (ArC), 77.8,
69.4(O-CH-), 31.8, 29.6, 29.5, 29.5, 29.3, 29.2, 28.9, 25.9, 22.6, 14.0 (-CH
2
-), 12.5 (-
CH
3
). MS (EI): m/z: 520.6, 429.4, 352.3, 261.1, 215.2, 183.1,83.0. Mp: 76 °C.
2’’-Benzyloxy-5’’-dodecyloxy [1, 4’; 1’, 1’’; 4’’, 1’’’; 4’’’, 1’’’’] quinquephenyl
(4b)
Compound 4b was synthesized according to the procedure described for the synthesis
of 4a. Yield: 4.5 g (33.6 %).
1
HNMR (300 MHz, CDCl
3
, δ ppm): 7.72 - 7.30 (m, Ar-

40
H, 23 H), 7.26 (s, Ar-H, 1 H), 7.07 (s, Ar-H, 1 H), 5.06 (s, ArO-CH

2
-, 2 H), 3.98 (t, J
= 6.3 Hz, ArO-CH
2
-, 2H), 1.73 (p, J = 6.8 Hz, R(O)-CH
2
-, 2H), 1.24 (b, -CH
2
-,18 H),
0.87 (t, J = 6.0 Hz, -CH
3
, 3H).
13
C NMR (75.4 MHz, CDCl
3
, δ ppm): 150.8, 149.8,
140.9, 139.8, 139.7, 137.3, 130.9, 130.3, 129.9, 129.8, 128.7, 128.3, 127.6, 127.2,
128.7, 128.7, 128.3, 127.6, 127.1, 127.0, 126.9, 126.7, 126.6, 117.3, 115.9, 98.1
(ArC), 71.9, 69.5 (O-CH), 31.8, 29.6, 29.6, 29.5, 29.3, 29.2, 26.0, 22.6, 14.0 (-CH
2
-),
11.3 (-CH
3
). MS (ESI): m/z: 672.4, 581.6, 413.2, 306.2, 289.2, 228.2, 153.1. Mp: 143
°C.
5’-Dodecyloxy [1, 1’, 4’, 1’’] terphenyl-2’-ol (5a)
21
To a 100 ml round-bottom flask containing 10% Pd/C (2.5 g) in 50 ml THF was
added 4a (2.6 g, 5 mmol). The flask was charged with nitrogen, and a balloon filled
with H

2
was fitted to the flask. The nitrogen was briefly evacuated from the flask, and
H
2
was charged above the solution. The mixture was stirred for 24 h at ambient
temperature and filtered through a glass frit containing a small layer of celite powder.
After the solid was washed with THF (3 × 25 ml), the organic fractions were
combined and the excess solvent was removed under reduced pressure to yield a
white powder. Yield: 2.02 g (93 %).
1
H NMR (300MHz, CDCl
3
, δ ppm): 7.42 - 7.40
(m, Ar-H, 6 H), 7.38 - 7.32 (m, Ar-H, 4 H), 4.90 (s, Ar-OH, 1H), 3.88 (t, J = 6.2 Hz,
ArO-CH
2
-, 2 H), 1.67 (p, J = 6.8 Hz, R(O)-CH
2
-, 2 H), 1.25 (b, -CH
2
-, 18 H), 0.88 (t,
J = 6.6 Hz, 3 H).
13
C NMR (75.4 MHz, CDCl
3
, δ ppm): 150.1, 146.3, 142.7, 140.7,
137.9, 137.2, 132.0, 131.8, 131.7, 131.2, 129.4, 129.1, 128.9, 127.8, 127.3, 126.9,
118.0, 115.3, 98.1 (ArC), 69.6 (O-CH-), 31.8, 29.6, 29.5, 29.5, 29.3, 29.2, 29.2, 25.9,
22.6, 14.1 (-CH
2

-), 13.9 (-CH
3
). MS (ESI): m/z: 430.2, 262.2, 149.0, 66.0. Mp: 61 °C.

5’’-Dodecyloxy [1, 4’; 1’, 1’’; 4’’, 1’’’; 4’’’, 1’’’’] quinquephenyl-2’’-ol (5b)

41
Compound 5b was synthesized according to the procedure described for the synthesis
of 5a. From 4.3 g of 4b was obtained 3.5 g of white powder. Yield: 3.4 g (93 %).
1
H
NMR (300 MHz, CDCl
3
, δ ppm): 7.73 - 7.46 (m, Ar-H, 18 H), 7.26 (s, Ar-H, 1 H),
7.07 (s, Ar-H, 1 H), 5.10 (s, Ar-OH, 1 H), 3.94 (t, J = 6.5 Hz, ArO-CH
2
-, 2 H), 1.72
(p, J = 6.7 Hz, -CH
2
-, 2 H), 1.24 (b, -CH
2
- 18 H), 0.89 (t, J= 4.0 Hz, 3 H).
13
C NMR
(75.4 MHz, CDCl
3
, δ ppm): 150.3, 146.3, 140.9, 129.8, 129.2, 128.8, 128.7, 127.8,
127.5, 127.1, 127.0 126.9, 126.5, 120.6, 118.8, 115.3, 98.1, 89.6 (ArC), 69.6 (O-CH),
31.8, 29.6, 29.5, 29.5, 29.3, 29.2, 28.8, 27.6, 26.0, 22.6 (-CH
2

-), 13.9 (-CH
3
). MS
(ESI): m/z: 582.4, 414.3. Mp: 146 °C.
5’-Dodecyloxy [1, 1’, 4’, 1’’] terphenyl-2’-yl methacrylate (6a)
Triethylamine (1.5 ml, 11 mmol) and compound 5a (2.15 g, 5 mmol) were dissolved
in a 50 ml dry THF placed in a 100 ml round-bottom flask. This solution was cooled
with ice, and a solution of methacryloyl chloride (1 ml, 10 mmol) in 4 ml THF was
added dropwise. After finishing the addition, the reaction mixture was stirred at room
temperature for 4 hr, filtered and the volatile components were removed under
reduced pressure. The resulting crude product was dissolved in dichloromethane,
washed with sodium bicarbonate solution and followed by water (3 × 50 ml), and the
organic layer was dried over anhydrous magnesium sulfate. Filtered the solution, and
the solvent was removed under reduced pressure to yield the monomer. Yield: 1.7 g
(68 %).
1
H NMR (300 MHz, CDCl
3
, δ ppm): 7.65 -7.28 (m, Ar-H, 10 H), 7.21(s, Ar-
H, 1 H), 7.03 (s, Ar-H, 1 H), 6.22 (s, CH
2
=C-, 1 H), 5.65 (s, CH
2
=C-, 1 H), 4.02 (t, J =
6.4 Hz, ArO-CH
2
-, 2 H), 2.0 (s, =C-CH
3
, 3 H), 1.68 (p, J = 6.9 Hz, R(O)-CH
2

-, 2 H),
1.25 (b, -CH
2
-, 18 H), 0.90 (t, J = 6.6 Hz, -CH
3
, 3 H).
13
C NMR (75.4 MHz, CDCl
3
, δ
ppm): 171 (C=O), 153.8, 141.2, 137.1, 136.6, 135.8, 134.6, 134.5, 133.8, 130.6,
129.3, 128.9, 128.8, 128.6, 128,6, 128.5, 126.6, 124.6, 114.5, (ArC, C=C), 62.9 (O-

42
CH-), 31.8, 29.6, 29.5, 29.4, 29.1, 29.0, 26.0, 25.9, 25.5, 21.1 (-CH
2
-), 18.2, 14.0 (-
CH
3
). MS (EI): m/z: 498.5, 430.5, 330.3, 289.2, 261.2. Mp: 45 °C.
5’’-Dodecyloxy [1, 4’; 1’, 1’’; 4’’, 1’’’; 4’’’, 1’’’’] quinquephenyl-2’’-yl
methacrylate (6b)
Monomer 6b was synthesized according to the procedure described for the synthesis
of 6a. From 2.2 g (3 mmol) of compound 5b was obtained 1.28 g of 6b. Yield: 1.28 g
(64.1 %).
1
H NMR (300 MHz, CDCl
3
, δ ppm): 7.73 - 7.36 (m, Ar-H, 18 H), 7.24 (s,
Ar-H, 1 H), 7.04 (s, Ar-H, 1 H), 6.18 (s, CH

2
=C-, 1 H), 5.65 (s, CH
2
=C-, 1 H), 3.98 (t,
J= 6.5 Hz, ArO-CH
2
-, 2 H), 2.02 (s, C=C-CH
3
, 3 H), 1.73 (p, J = 6.6 Hz, R(O)-CH
2
-,
2 H), 1,26 (b, -CH
2
-, 18 H), 0.87 (t, J = 6.7 Hz, -CH
3
, 3H).
13
C NMR (75.4 MHz,
CDCl
3
, δ ppm): 166 (C=O), 150.3, 146.3, 140.9, 129.8, 129.1, 128.8, 128.7, 127.8,
127.5, 127.1, 127.0 126.9, 126.5, 120.7, 118.7, 115.2, 98.1, 89.6 (ArC), 69.4 (O-CH-
),31.8, 29.6, 29.5, 29.4, 29.2, 29.1, 28.7, 27.5, 26.0, 22.6 (-CH
2
), 18.4, 14.0 (-CH
3
).
MS (EI): m/z: 650.4, 581.4, 482.2, 413.1, 69.1. Mp: 115 °C.
Poly(5’-dodecyloxy [1, 1’, 4’, 1’’] terphenyl-2’-yl methacrylate) (7a)
Monomer 6a (1.5 g, 3 mmol) and 2, 2’-azobisisobutyronitrile (AIBN) (0.02 g, 0.01

mmol, 0.3 mol%) were dissolved in 20 ml dry THF. Purged with nitrogen for 30 min,
heated to 70-80 ºC and stirred for 18 h under nitrogen flush. The polymer 7a was
isolated via precipitation from methanol. Yield: 1.22 g (81 %).
1
H NMR (300MHz,
CDCl
3
, δ ppm): 7.66 - 7.32(b, Ar-H, 10 H), 7.07-7.00(b, Ar-H, 2 H), 3.95(b, ArO-
CH
2
- 2 H), 1.75-1.65(b, R(O)-CH
2
-, 4 H), 1,24(b, -CH
2
-, 18 H), 0.87(b, -CH
3,
6 H).
FT-IR (KBr, cm
-1
): 3030 (ArH stretching), 2928 (-CH
2
- stretching), 1724 (ester C=O
stretching), 1515, 1478, 1390, 1370 (Ar, C=C stretching), 1268, 1165, 1020 (C-O-C
stretching).

43
Poly(5’’-dodecyloxy [1, 4’; 1’, 1’’, 4’’, 1’’’; 4’’’, 1’’’’] quinquephenyl-2’’-yl
methacrylate ) (7b)
Polymer 7b was synthesized according to the procedure described for the synthesis of
7a. From 1.0 g of monomer 6b was obtained 0.52g of polymer 7b. Yield: 0.52g

(52%).
1
H NMR (300MHz, CDCl
3
, δ ppm): 7.66 - 7.32(b, Ar-H, 18 H), 7.07 - 6.87(b,
Ar-H, 2 H), 3.90(b, ArO-CH
2
-, 2 H), 1.75-1.65(b, R(O)-CH
2
-, 4 H), 1,24(b, -CH
2
-, 18
H), 0.87(b,-CH
3
, 6 H). FT-IR (KBr, cm
-1
): 3067 (ArH stretching), 2920 (-CH
2
-
stretching), 1724 (ester C=O stretching), 1626, 1602, 1527 (Ar, C=C stretching),
1268, 1150, 1020 (C-O-C stretching).
1,3-Bis (5'-dodecyloxy [1, 1'; 4', 1''] terphenyl-2'-yloxy)-propan-2-ol (8a)
To a 250 ml three neck round bottom flask fitted with a reflux condenser, addition
funnel, and a nitrogen inlet were added 100 ml DMF, compound 5a (4.3 g, 10 mmol)
and potassium carbonate (2.1 g, 20 mmol). Under nitrogen flush, the mixture was
heated to 80 °C and stirred for 1 hr. A solution of 1,3-dibromo-2-propanol (0.8 ml, 3.5
mmol, d 2.12) in 25 ml DMF was added dropwise. The reaction mixture was stirred
at 80 °C for 12 hr and filtered. The volatile components were removed under reduced
pressure and excessive phenol was removed by washing with 2M sodium hydroxide
and water (3 × 100 ml). The resulting crude product was purified with column

chromatography on a silica gel column using hexane and dichloromethane (10:1) as
the eluant. Yield: 2.2 g (68.7 %).
1
H NMR (300 MHz, CDCl
3
, δ ppm): 7.59 - 7.29(m,
Ar-H, 20 H), 6.94(s, Ar-H 2 H), 6.92(s, Ar-H, 2 H), 4.05(m, R-CH-O, 1H), 3.93(m,
O-CH
2
-, 4 H), 3.91(m, ArO-CH
2
-, 4 H), 2.03(s, Ar-OH, 1 H), 1.68(b, R(O)-CH
2
-, 4
H), 1.25(b, -CH
2
-, 36 H), 0.88(t, J = 6.7 Hz, -CH
3
, 6 H).
13
C NMR (75.4 MHz, CDCl
3
,
δ/ppm): 154.2, 146.3, 140.9, 129.8, 129.1, 128.8, 128.6, 127.8, 127.4, 127.1, 127.0
126.9, 126.5, 120.6, 118.7, 115.2, 98.1, 89.6 (ArC), 69.6, 69.4, 69.2 (-O-CH
2
-), 31.8,

44
29.6, 29.5, 29.4, 29.3, 29.2, 29.1, 25.9, 22.5, 14.4 (-CH

2
-), 13.99 (-CH
3
). MS (ESI):
m/z: 916.7, 486.4, 430.3, 262.3.
1, 3-Bis (5''-dodecyloxy [1, 4'; 1', 1'', 4'', 1'''; 4''', 1''''] quinquephenyl-2''-yloxy)
propan-2-ol (8b)
Compound 8b was synthesized according to the procedure described for the synthesis
of 8a. From 4.0 g of compound 5b was obtained 1.7 g compound 8b. Yield: 1.7 g
(60.7 %).
1
H NMR (300 MHz, CDCl
3
, δ ppm): 7.68 - 7.36(m, ArH, 36 H), 7.10(s,
ArH, 2 H), 7.04(s Ar-H, 2 H), 4.16(b, R-CH(O)-R, 1H), 4.06(m, O-CH
2
-, 4H), 3.95
(b, ArO-CH
2
-, 4 H), 3.48(b, Ar-OH, 1 H), 1.68(b, R(O)-CH
2
-, 4H), 1.23(b, -CH
2
-, 38
H), 0.87(t, J = 6.7 Hz, 6 H).
13
C NMR (75.4 MHz, CDCl
3
): 150.3, 146.3, 140.9,
129.8, 129.1, 128.8, 128.6, 127.8, 127.4, 127.1, 127.0 126.9, 126.5, 120.6, 118.7,

115.2, 98.1, 89.6 (ArC), 69.6, 69.4, 69.1 (O-CH-), 31.8, 29.6, 29.5, 29.4, 29.25, 29.2,
28.7, 27.5, 26.0, 22.6 (-CH
2
-), 13.9 (-CH
3
). MS (ESI): m/z: 1220.5. Mp: 151 °C.
1, 3-Bis (5'-dodecyloxy [1, 1'; 4', 1''] terphenyl-2'-yloxy)-2-propyl methacrylate
(9a)
Monomer 9a was synthesized according to the procedure described for the synthesis
of 6a. From 3.1 g of compound 8a (2 mmol) was obtained 1.2 g of 9a. Yield: 1.2 g
(54 %).
1
H NMR (300MHz, CDCl
3
, δ ppm): 7.65 -7.29 (m, Ar-H, 20 H), 6.94 (s, Ar-
H, 2 H), 6.92 (s, Ar-H, 2 H), 6.10 (s, CH
2
=C-, 1 H), 5.56 (s, CH
2
=C-, 1 H), 5.35 (p, J
= 5.1 Hz, R(O)-CH-R(O), 1 H), 4.06 (d, J = 5.8 Hz, O-CH
2
-R(O), 4H), 3.91 (t, J= 6.6
Hz, ArO-CH
2
-, 4 H), 2.02 (s, C=C-CH
3
, 3 H), 1.68 (b, R(O)-CH
2
-, 4 H), 1.25 (b, -

CH
2
-, 36 H), 0.87 (t, J = 7.0 Hz, -CH
3
, 6 H).
13
C NMR (75.4 MHz, CDCl
3
, δ ppm):
166.5 (C=O), 153.8, 146, 140.9, 137, 135.5, 134.4, 127.7, 126.4, 126.2, 126.0, 125.6,
124.9, 122.0, 120.66, 118.78, 117.7, 98.1, 89.6 (ArC, C=C), 70.2, 69.4, 66 (O-CH
2
-),

45
31.82, 29.57, 29.53, 29.45, 29.35, 29.22, 29.16, 25.96, 22.58 (-CH
2
-), 18.4, 14.2 (-
CH
3
). MS (SI): m/z: 984.9, 541.5, 469.5, 262.4. Mp: 65 °C.
1, 3-Bis (5''-dodecyloxy [1, 4'; 1', 1''; 4'', 1'''; 4''', 1''''] quinquephenyl-2''-yloxy) -
2-propyl methacrylate (9b)
Monomer 9b was synthesized according to the procedure described for the synthesis
of 6a. From 0.9g of compound 8a (0.75 mmol) was obtained 0.72 g of 9b. Yield: 0.72
g (85 %).
1
H NMR (300 MHz, CDCl
3
, δ ppm): 7.68 - 7.36 (m, Ar-H, 36 H), 7.10 (s,

Ar-H, 2 H), 7.04 (s, Ar-H, 2 H), 6.21 (s, CH
2
=C-, 1 H), 5.63 (s, CH
2
=C-, 1 H), 5.33(p,
J = 4.8 Hz, R(O)-CH-R(O), 1 H), 4.05 (d, J = 4.5 Hz, O-CH
2
-R(O), 4 H), 4.06 (t, J =
6.8 Hz, ArO-CH
2
-, 4 H), 2.0 (s, C=C-CH
3
, 3 H), 1.68 (p, J = 6.9 Hz, R(O)-CH
2
-, 4 H),
1.23 (b, Ar-H, 38 H), 0.87 (t, J = 6.7 Hz, 3 H).
13
C NMR (75.4 MHz, CDCl
3
, δ ppm):
166.5 (C=O), 150.3, 146.3, 140.9, 129.8, 129.1, 128.8, 128.6, 127.8, 127.4, 127.1,
127.0, 126.9, 126.5, 120.6, 118.7, 115.2, 98.1, 89.6 (ArC, C=C), 70.2, 69.4, 66 (O-
CH
2
-), 31.8, 29.6, 29.5, 29.4, 29.2, 29.1, 28.7, 27.5, 26.0, 22.6 (-CH
2
-), 18.2,13.9 (-
CH
3
). MS (ESI): m/z: 1289.0. Mp: 60 °C.

Poly(1, 3-bis (5'-dodecyloxy [1, 1'; 4', 1''] terphenyl-2'-yloxy)-2-propyl
methacrylate) (10a)
Polymer 10a was synthesized according to the procedure described for the synthesis
of 7a. From 1.0g of monomer 9a (0.1 mmol) was obtained 0.67 g of white powder.
Yield: 6.7 g (67 %).
1
H NMR (300 MHz, CDCl
3
, δ ppm): 7.55 - 7.33 (b, Ar-H, 20 H),
6.93 - 6.87 (b, Ar-H, 4 H), 5.21 (b, R(O)-CH-R(O), 1 H), 4.10 - 3.87 (b, O-CH
2
-, 8H),
1.84 (b, R(O)-CH
2
-, 4 H), 1,60 (b, -CH
2
-, 2 H), 1.25 (b, -CH
2
-, 36 H), 0.88 (b, -CH
3
,
9H). FT-IR (KBr, cm
-1
): 3073 (ArH stretching), 2928 (-CH
2
- stretching), 1720 (ester
C=O stretching), 1545, 1515, 1470, 1390(Ar, C=C stretching), 1204, 1140, 1058 (C-
O-C stretching).

46

Poly(1, 3-bis (5''-dodecyloxy [1, 4'; 1', 1''; 4'', 1'''; 4''', 1''''] quinquephenyl-2''-
yloxy)-2-propyl methacrylate) (10b)
Polymer 10b was synthesized according to the procedure described for the synthesis
of 7a. From 0.8 g of monomer 9b (0.6 mmol) was obtained 0.5 g of 10b. Yield: 0.5 g
(62.5 %).
1
H NMR (300 MHz, CDCl
3
, δ ppm): 7.60 - 7.37 (b, Ar-H, 36 H), 6.93 -
6.87 (b, Ar-H, 4 H), 5.34 (b, R(O)-CH-R(O), 1H), 4.4-3.97 (b, O-CH
2
-, 8H), 1.84 (b,
R(O)-CH
2
-, 4 H), 1,60 (b, -CH
2
-, 2 H), 1.25 (b, -CH
2
-, 36 H), 0.88 (b,-CH
3
, 9 H). FT-
IR (KBr, cm
-1
): 3030 (ArH stretching), 2928 (-CH
2
- stretching), 1720 (ester C=O
stretching), 1545, 1526, 1480 (Ar, C=C stretching), 1268, 1165, 1115 (C-O-C
stretching).
2.1.3 Results and discussion
2.1.3.1 Synthesis of polymers

The polymers were synthesized through radical polymerization from the appropriate
monomers. The concentration of initiator AIBN was 0.5 mol % based on the amount
of the monomer used. The molecular weight of polymer 7a, 7b, 10a, and 10b were
estimated by GPC using a solution of polymers in THF. The results are shown in
Table 2.1.1.
Table 2.1.1. Number–average (M
n
) and weight-average (M
w
) molecular weight of
polymers

Polymer M
n
M
w
PD
7a
0.56 × 10
4
0.69 × 10
4
1.2
7b
0.42 × 10
4
0.68 × 10
4
1.6
10a

0.75 × 10
4
1.20× 10
4
1.6
10b
0.60 × 10
4
1.10× 10
4
1.8

The molecular weights of these polymers are low compared with unsubstitued
PMMA. This result may be due to the structure of our monomers. In the monomer,

47
the conjugated side chain group is much larger than the methacrylate carbon-carbon
double bond. This will result in a big steric hindrance when radical polymerization is
carried out. The double bonds must react before the radical center is quenched. In our
case, all the monomers have a large side group and form a very sterically crowded
environment. This leads to the separation of radical centers and thereby retards the
rate of polymerization. It is difficult to obtain a high molecular-weight polymer
through normal radical polymerization.
Recently, there are some published reports about the polymerization of the
macromonomers through radical polymerization. The new strategy is to increase the
concentration of the initiator and the monomers
22
.

2.1.3.2 NMR and FTIR analysis

The structures of all monomers and polymers prepared in our work were characterized
by
1
H NMR and FTIR. Figure 2.1.1 illustrates two representative
1
H NMR spectra of
monomer 6a and polymer 7a. In the
1
H NMR spectra of monomer 6a, for example,
the signals appearing in the range of δ 7.75 –6.94 correspond to those in aromatic
protons. The double peak at δ 6.22 and 5.65 are characteristic of methacrylic carbon
double bond protons. It is noted that in the spectrum of polymer 7a, these two signals
disappears. The structure of the polymers was characterized by means of infrared
spectroscopy (IR). The spectrum of polymer 7a is shown in Figure 2.1.2 as an
example. The IR spectrum shows typical peaks for aromatic hydrogen stretching at
3030 cm
-1
and alkyl hydrogen stretching at 2928 cm
-1
. The peak of 1724 cm
-1
is
attributed to the ester group C=O. The strong peaks at 1204 cm
-1
, 1140 cm
-1
, 1058 cm
-
1
region are assigned to C-O stretches. The absence of a C=C band at 1640 cm

-1

indicates that the monomer has been polymerized completely.

48

Figure 2.1.1.
1
H NMR spectra of 6a and 7a in CDCl
3



Figure 2.1.2. The FT-IR spectrum of polymer 7a in KBr


49
2.1.3.3 Thermal properties
The thermal stability of the novel polymers in nitrogen atmosphere was evaluated by
thermogravimetric analysis (TGA), which is given in Figure 2.1.3. Polymer 7a
showed a weight loss at 258 °C at a heating rate of 10

°C /min. Polymer 7b also
showed a weight loss starting at 175

°C while polymer 10a and 10b showed a weight
loss at a higher temperature, 230 °C and 245 °C, respectively. Two significant
changes in the slopes of the degradation curves can be observed for the polymers.
This two-step decomposition resulted from the special structures of the polymers. The
polymers is composed with two components, one is the polymer methacrylate

backbone, which decompose at 200-300 °C.
0 200 400 600
100
10b
10a
7b
7a
Weight lose (%)
Temperature (
o
C)



Figure 2.1.3. TGA traces of polymer 7a, 7b, 10a, and 10b measured in nitrogen
atmosphere


The polymers were also characterized using differential scanning calorimetric (DSC)
at a heating rate of 10

°C /min, which is shown in Figure 2.1.4. A glass transition was
observed at about –3.2

°C for polymer 7a. The DSC plots of polymer 10a, 7b and 10b

50
showed a T
g
at 4.5

°C, 34.3 °C and 74.5

°C respectively. With the increase of the
phenyl group, the T
g
of the polymer increases.

0100200
Tg=74.5
0
C
Tg=34.3
0
C
Tg=4.5
0
C
Tg=-3.2
0
C
10b
10a
7b
7a
Heat Flow
Temperature (
o
C)

Figure 2.1.4. DSC traces of polymer 7a, 7b, 10a, and 10b measured in nitrogen
atmosphere

2.1.3.4 X-ray analysis

XRD measurements were used to characterize the polymer lattice. The X-ray
diffraction profiles of the four polymers are similar. Figure 2.1.5 shows the XRD
patterns of polymer 10a and 10b as representative. Polymer 10a shows a broad peak
at 18.5 ° while polymer 10b shows a peak at 21.5°. No higher order peak is detected,
indicating polymers appear to have poor lattice structure. The bulk polymer is
considered to take an amorphous nature.
2.1.3.5 Polarized optical microscopy study

The thermotropic liquid crystal polymers possess an intrinsic optical anisotropy
(double refraction). Depending on the orientation of the liquid crystals, different
textures may be observed, and used for identification of the liquid crystal phase.
Figure 2.1.6 shows the photomicrograph of the liquid crystalline state of the

51
monomer 9a. The monomer 9a forms a liquid crystalline state at 110

° C while its
melt point is about 78 °C. A typical texture of nematic phase is observed. However,
after polymerization, the polymer showed a T
g
transition with no liquid crystalline
phase.

10 20 30

0
200
400
10b
10a
Intensity (a.u.)
2-Theta



Figure 2.1.5. WAXS profiles of the polymer 10a and polymer 10b at room
temperature





Figure 2.1.6 Polarized optical micrograph of monomer 9a, taken at 110 °C



52
It is well known that the main chain of jacketed polymers may take a rigid
conformation due to the steric repulsion between the densely grafted side chains and
excluded volume effects. Such polymers show similar properties of semi-rigid or rigid
main chain polymers. DSC traces can show special entropy changes accompanied by
a transition from anisotropic liquid to isotropic liquid. The same strategy is taken in
the design of our polymer structure on which big conjugated phenyl groups are
incorporated in the side chain and force the main chain to take a rigid conformation.
However, all polymers did not show a liquid crystalline phase. Only T

g
changes were
observed in the DSC data. It is also confirmed that the polymers appeared to have an
amorphous conformation from the X-ray diffraction studies. It is believed that in
small liquid crystalline molecules, if the alkyl chains are grafted in the lateral position
at the rigid core, the order arrangement of the molecules is strongly disturbed
23, 24
. In
our polymers, the flexible alkyl chains are also attached to the lateral position of the
terphenyl rigid rod, which has a great steric effect on the alignment of the calamitic
cores. At the same time the lateral alkyl chains are incompatible to the aromatic cores
whereas it is completely compatible with the backbone. This tendency also gives rise
the disturbance to the ordered arrangement of the polymers. Therefore no order
appears in the bulky polymer 7a and 7b. The disturbance is so strong that the polymer
10a and 10b still appear amorphous even when the rigid core increases to pentaphenyl
groups, which is believed to create ordered packing.
Based on our preliminary results, two methods are proposed to solve the problem.
First, novel jacketed polymer without the alkyl chains may induce some packed order.
Second, the repulsive interaction between some polar and non-polar units can be
incorporated on the side chains so that the microseparation is enhanced in the self-
assembly of the novel polymers.

53
2.1.4 Conclusion

A series of novel jacketed polymers were synthesized, and characterized using GPC,
DSC, TGA, FTIR, NMR, and X-ray diffraction studies. The results indicate that the
novel jacketed polymers take an amorphous conformation and results from DSC and
POM analysis showed no liquid crystalline properties.

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55