Liquid diene mesogens

Cho et al. described the synthesis and polymerization of 4,8-cyclododeca-dien-l-yl-(4 -methoxy-4-biphenyl) terephthalate VIII [54,55]. Polymerization was carried out with WCl4(OAr)2/PbEt4. The double bonds in the polymer backbone were subsequently hydrogenated with H2/Pd(C), leading to a SCLCP with a fully saturated hydrocarbon backbone. This polymer system had a very flexible polymer backbone but a stiff connection between the main chain and the mesogenic unit. The distance between two adjacent side chains was about 12 methylene units. This very flexible main chain allowed the polymer to organize into a LC mesophase. Both polymers - the unsaturated and the saturated -showed smectic liquid crystalline mesophases with almost the same transition temperatures (see Table 5). 

Researchers at the University of Hull undertook comparisons between model liquid crystalline compounds and related reactive mesogens, which form nematic mesophases using two different conjugated cores containing the fluorene moiety, see Chaps. 7 and 8. In one study, based on a biphenyl-bithiophene-fluorene(compound HI), core time of flight measurements were carried out in the nematic phase of the model compound, the nematic phase of the diene substituted RM and on the crosslinked compound at room temperature [34], They found a large drop in hole mobility between the model compound and the nematic phase of the RM from 8 X 10 " to 1.5 X 10 cm s There was a small recovery in hole mobility... 

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