An optically active monomer containing azobenzene moieties with chiral group (s-2-methyl-butyl), 4-[2-(methacryloyloxy)ethyloxy] -4'-(s-2-methyl-1-butyloxycarbonyl) azobenzene (M1) was synthesized. Polymer (PM1) possessing optical phase conjugated response was obtained by homopolymerization of the optically active monomer (M1) using free radical polymerization. The polymer was very soluble in common solvents and good optical quality films could be easily fabricated by spin coating. The optical phase conjugated responses of the polymer PM1 were measured by degenerate four-wave mixing (DFWM). In comparison with polymer containing no chiral group, it was found from the preliminary measurement of photoisomeric change that optical phase conjugated response of the PM1 in the long-range order hexagonal symmetry microstructure could be easily controlled by choosing the appropriate polarization direction of the irradiating beams (514.5 nm) and the irradiating number, presumably due to the chiral group in the PM1 molecular structure. For the case of the polymer investigated here, a chiral group side chain was introduced to increase optical phase conjugated response intensity with different polarization directions of the irradiating beams, which aims originally at searching for a new photoactive material.
The liquid crystallinity of poly(N-vinylcarbazole) was studied by using powder X-ray diffraction, polarized opticalmicroscopy, and differential scanning calorimetry. The results show that the lower molecular weight fractions of this polymerdo not form a liquid crystalline phase, while the samples of sufficiently high molecular weight do form a mesophase attemperatures above the glass transition. The lowest value of the degree of polymerization for PVK to form a stable liquidcrystalline phase was found to be in the range of 150 to 200, significantly higher than the value of 50 for most conventionalside chain liquid crystaline polymers.
Novel side-chain liquid-crystalline poly(meth)acrylates were synthesized using 1-(3-hydroxyl-propyl)-3-[(4 '-cyano-p-terphenyloxycarbonyl)alkyl]-1,1,3,3-tetramethyldisiloxane as the key intermediate. The polymers used a disiloxane moiety as decoupling spacer with cyano-p-terphenyl as mesogenic unit. The products were characterized by NMR, GPC, DSC and polarizing optical microscopy. All the polymers with cyano-p-terphenyl mesogens formed a stable mesophase. However, if the mesogenic unit is replaced by cyano-p-biphenyl, the liquid crystalline character will be lost. The results also showed that the decoupling is incomplete even if a complex and very flexible decoupling spacer is deliberately incorporated to obtain the highest possible decoupling effect.
Mesogen-Jacketed liquid crystalline polymers were synthesized in various chiral conditions using 1) (\|)\|menthol as a reaction solvent (additive),2) (\|)\|dimenthyl peroxydicarbonate as a chiral free radical initiator,3) menthyl methacrylate as a comonomer for copolymerization,4) (-)-sparteine-fluorenyllithium as a chiral anionic initiator and 5) a chiral monomer.In the polymerization using a chiral initiator or a chiral solvent,the helix-sense-selection was not found.In the case of the copolymerization,the chiral monomeric unit incorporated into the polymer chain was found to induce liquid crystallinity.Chiral mesogen-Jacketed polymer was also synthesized from chiral monomer 5.However,this polymer did not form a liquid crystal phase although it met the model of Mesogen-Jacketed liquid crystalline polymers.
Two monomers of 2, 5-bis (4’-methoxybenzoyloxy) benzyl acrylate and 2, 5-bis (4’-methoxy- benzoyloxy)benzyl methacrylate and their corresponding polymers were successfully synthesized. The mesomorphic behavior of both polymers was examined using differential scanning calorimetry(DSC) and polarized optical microscopy(POM). It was found that both polymers are noncrystalline with a glass transition temperature of 73. 1℃ for poly-[2, 5-bis(4’-methoxybenzoyloxyben acrylate] and 120. 3℃ for poly-[2’ 5-bis (4’-methoxybenzoyloxy ) benzyl methacrylate], above which liquid crystalline state is formed. The clearing temperature of the former is 178. 3℃ and that of the latter is 172. 8 ℃.
