| Abstract: | A series of a segmented copolymer, poly(4,4′-dioxy-2,2′-dimethyl-azoxybenzene dodecanedioyl)-co-polyoxyethylene 400 (PMABD-co-POE) was prepared; the average chain lengths n, of the PMABD studied are 8.1 to 20.6. The thermotropic properties and the mesophase texture of the segmented copolymers were elucidated as functions of n using a differential scanning calorimeter and a polarized optical microscope with a hot stage. The results show that the incorporation of POE with PMABD decreases the intermolecular interaction force and changes the chain flexibility. The nematic droplets obtained near the isotropic temperature all exhibited a twisted bipolar configuration. Also, in the undercooling process, the nematic textures obtained before crystallizing varied with n. The copolymers containing n ≥ 17, like PMABD, develop a Schlieren texture, whereas those containing n < 17 develop a distorted-stripe conformation. A possible mechanism for interpretation of the obtained results has been proposed. © 1995 John Wiley & Sons, Inc. |
