Chapter Conclusions 157 Considerable research interests are focused on synthetic polymer design strategies that provide greater control over polymer size and shape than hitherto possible in commercial polymers. Molecular stiffness enables the precise placement and functional control of shape-persistent polymers. Stiff polymers, combined with precise molecular placement, are good candidates for the construction of fine microstructure. Compared with normal rigid building blocks, the jacketed polymers have great advantages for the synthesis. In our approach, the conjugated rigid group was chosen as side groups. Besides the steric crowding, the rigid properties of the side chains help polymers to take some ordered conformation. Terphenyl or pentaphenyl group using as a laterally attached mesogenic core incorporated on the side chain is rarely reported. The sufficient electronic interaction between theses groups is expected to help the self-assembly of the polymers. The length of the alkyl chain and position of the alkyl chain on the mesogenic units appears to have significant effect on the self-assembly. Besides microseparation between rigid segments and flexible segments, polar or nonpolar effect is investigated through the incorporation of the polar functional groups. A series of novel jacketed polymers were synthesized according to this strategy. Strong electrostatic, weak van der Waals interactions, and geometrial effects were incorporated on the mesogens attached to the polymer backbone to control the self-assembly of polymer chains in the lattice. DSC and POM results show that the polymers with pyrimidine groups on the aromatic rigid core exhibits mesophase with an isotropic transition at 105 °C. X-ray diffraction experiments indicate a rectangular column-type mesophase with the lattice constants a = 35.87 Å and c = 58.92 Å. Studies on structureproperty relationship of the polymers incorporated with alkyl chains and pyrimidine 158 groups revealed that the alkyl chains in the lateral position on the rigid core exert hindrance to self-assembly whereas the pyrimidine groups stabilized the self-assembly of jacketed polymers. A series of novel jacketed liquid crystalline polymers, in which the terphenyl aromatic rigid core with alkyl chains on the terminal position attached laterally to the polymer backbone with a short spacer, were synthesized and characterized. All polymers were characterized using GPC, TGA, DSC, POM and XRD. The DSC, POM and XRD results show that poly (4, 4”-dibutoxy-5’-methoxy [1, 1’, 4’, 1”] terphenyl-2’-yl acrylate) (P1C4) exhibits a nematic mesophase, which undergoes an isotropic transition at 156°C. When the number of carbon atoms in the terminal alkyl chains of the terphenyl rigid core increase to10 (poly (4, 4”-didecyloxy-5’-methoxy [1, 1’, 4’, 1”] terphenyl-2’-yl acrylate) (P1-C10) and poly (1, 3-bis (4, 4”-didecyloxy-5’-methoxy [1, 1’, 4’, 1”] terphenyl-2’yloxy)-2-propyl acrylate) (P2-C10)), a smectic mesophase with an isotropic transition at 81.1 and 76.2 °C were observed. XRD patterns indicated a layer distance d of 21.2 Å and 18.6 Å, respectively. The results reported here demonstrated that the meophase of the terphenyl-incorporated polymers could be manipulated by modifying the length of the pendant alkyl groups. A series of complexes from poly (4-dodecyloxy-2, 5-bis (pyrimidin-5-yl)-phenyl-1-yl methacrylate) P1 and dodecylbenzenesulfonic acid (DBSA) were prepared and characterized. In the FTIR data, the peak at 1552 cm-1 of host polymer shifts to 1634 cm-1 corresponding to protonated pyrimidinium ring in the complexes. DSC results showed that only when the DBSA content in the complex is low (x = 0.5), liquid crystalline properties with an isotropic change at 107.5 °C while a Tg at 29.3 °C was observed. POM 159 and X-ray studies indicate that the complexes gradually lose the long order with the increase of DBSA content. AFM results reveal that P1(DBSA)0.5 takes a spherical morphology in contrast to the fibrous structure of pristine polymer. A series of novel chromophore rich polymers towards developing radiation sensitive materials as e-beam resist were synthesized and characterized. The polymers were characterized using FTIR, NMR spectroscopy, GPC, DSC and TGA measurements. These polymers showed strong fluorescence emission in the region of 330 - 380 nm and can be patterned by an electron beam in pure form or mixed with other components. All polymers also generated intense emission in the range of 510 - 565 nm when reconstructed by a laser source operating at a wavelength of 488 nm. The sensitivity of the polymeric fluorescence label as an e-beam resist was also discussed. 160 . core exert hindrance to self- assembly whereas the pyrimidine groups stabilized the self- assembly of jacketed polymers. A series of novel jacketed liquid crystalline polymers, in which the terphenyl. expected to help the self- assembly of the polymers. The length of the alkyl chain and position of the alkyl chain on the mesogenic units appears to have significant effect on the self- assembly. Besides. between rigid segments and flexible segments, polar or nonpolar effect is investigated through the incorporation of the polar functional groups. A series of novel jacketed polymers were synthesized