Triphenylene spacer

Complexes of polymeric acceptors and monomeric donors are also effective in inducing discotic PLCs. This was shown, in particular, for a main chain polyester into which TNF was incorporated, mixed with a triphenylene derivative [73]. In order to avoid phase separation, the donor concentration must exceed the acceptor concentration by a mole ratio of at least 3 1. It was also demonstrated that the alkyl spacer length in the main chain can be critical to the definition and stability of the discotic mesophase obtained. As illustrated in Figure 3.32, spacer lengths which are either too short or too long can inhibit the incorporation of the polymeric acceptor into the donor columns, the... 

Till now only few examples of discotic liquid crystalline polymers are known. In the first example described in literature (1),hexasubstituted triphenylene cores as discotic sidegroups, are linked to a polysiloxane backbone via a flexible alkyl spacer. Discotic main chain polymers (2,3) posses as disclike core benzene or tripenylene derivatives with the same high degree of substitution, i.e. six. 

Discotic architectures that use a central triphenylene core with six peripheral triphenylene units also exhibit colunmar mesophases, and these are commonly called star-like liquid crystals. Compoimd 28 is a very large molecule that uses flexible spacers to attach peripheral triphenylene units to a central discotic core in a star-like manner. The hexagonal columnar phase of compound 28 has been identified as hexagonal. Such stractmes are ohgomeric and could almost be considered polymeric (see Chapter 5). 

Zhu YF, Tian HJ, Wu HW, Hao DZ, Zhou Y, Shen ZH, et al. Ordered nanostruetures at two different length scales mediated by temperature a triphenylene-containing mesogen-jacketed liquid crystalline polymer with a long spacer. J Polym Sci A Polym Chem 2014 52 295-304. 

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