Broad Temperature Range of Chiral Smectic C Phase in Some Ferroelectric Side-Chain Liquid Crystalline Polysiloxanes Cont
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In this study, a series of new chiral smectic liquid crystalline polysiloxanes and containing oligooxyethylene spacers and 4-(S)-2-methyl- I -butyl (4-hydroxybiphenyl-4'-carbonyloxy) benzoate and 4-(S)-2-methyl- 1-butyl (4-hydroxyphenyl-4'-carbonyloxy) biphenyl carboxylate mesogenic side groups are synthesized. Their characterizations by differential scanning calorimetry, optical polarizing microscopy and X-ray diffraction have been presented. EXPERIMENTAL SECTION A. Mterials Poly (methylhydrogensiloxane) ( Mn=2270 and divinyltetramethylsiloxane platinum catalyst were obtained from Patrarch system Inc.), and used as received. S-(-)-2-Methyl-lbutanol, [a]D = -6.5' (from Merck), Allyl bromide, 2-chloroethanol, 2-(2chloroethoxy)ethanol, 2-(2-(2-chloroethoxy)ethoxy)ethanol, 4-hydroxy-4'-biphenylcarboxylic acid (Aldrich), methyl 4-hydroxybenzoate, 4-hydroxybenzoic acid, 4,4'-dihydroxybiphenyl (TCI), 2-allyloxyethanol and 4-hydroxybiphenyl-4'-carboxylic acid (from Tokyo Kaisei Co.) were used as received. Toluene used in the hydrosilation reaction was refluxed over sodium and distilled under nitrogen atmosphere. HC =CHCHBr
+
H-f OCH 2CH2 t-OH
I
NaOH
OCH 2CH2 t•OH H 2C = CHCH -2
ITsCI
pyridine
H2C=CHCIL"1OCH2CH2 "OTs n=1,2,3
+
HO--O.Q
"COOlI
IKOH,
1, 2, A
HO -0--COOH
O ,K
KI
EtOH
HOCH2 HCH, H2C =CHCH 2-- OCH 2CH, -tO--O u=1,2,3
4, 5.6
-'OCOOH
ISOCI,,
SHSO, Benlzene
CH 2C 12
DMF
H2C = CHCH2"f OCH2CIt,
t
00• 0
H2C=CHCH2IOCH2CH2 j-2
HO--O-COOCHC*HCH,
C000C
7
11
CH3 o--O-CO oo-O-*oo.C,14 9
IM - HIM
n=1.2,3
Scheme I. Synthesis of monomers IM-IIIM
698
CH3
-
B. Techniques 1 H-NMR spectra (300 MHz) were recorded on a Varian VXR-300 spectrometer. FT-IR spectra were measured on a Nicolet 520 FT-IR spectrometer. Polymer samples were cast film on a KBr tablet for the IR measurements. Thermal transitions and thermodynamic parameters were determined by using a Seiko SSC / 5200 differential scanning calorimeter equipped with a liquid nitrogen cooling accessory. Heating and cooling rates were 10 'C / min. Thermal transitions reported were collected during the second heating and cooling scans. A Carl Ziess Axiophot optical polarized microscope equipped with a Mettler FP 82 hot stage and a FP 80 central processor was used to observe the thermal transitions and to analyze the anisotropic textures. Preparative gel permeation chromatography (GPC) was run on a Waters 510 LC instrument equipped with a 410 differential refractometer and a preparative GPC column ( 22.5 mm x 60cm ) supplied by American Polymer Standard Co. X-ray diffraction measurements were performed with nickel-filtered CuKa-radiation using a Rigaku powder diffractometer. Optical rotations were measured at 25 TC on a Jasco DIP- 140 polarimeter with chloroform as solvent for all compounds.
C. Synthesis of Monomers The synthesis of olefinic monomers IM-IIIM for hydrosilylation reaction and monomers IVM-VIM are outlined in Schemes I and II. + H-fOCH2CH 2 I.-ci
Ho-O-cocH,
I KCOICHCN H-f OCHt2CH2 n=l.2,3
o-43-CO 2 C.,
9,10,11,
t0
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