Methylene groups, intercalated smectics

In a model study aimed at elucidating the behavior of the polymers, Watanabe found that the dimer polymethylene diol diesters of type 7 (Figure 8.18) formed smectic phases.38 When the spacer between the two mesogenic units in the dimer had an odd number of methylene groups (diester 7 has nine methylenes in the spacer), then an intercalated tilted smectic structure with all anticlinic layer interfaces was formed. This structure is often termed SmC2 in the literature. As for the B6 phase, all of the layer interfaces in this structure are equivalent, and the X-ray layer spacing is less than half the fully... 

Figure 8.18 Smectic dimer of Watanabe, possessing an odd number of methylene units in linking group. This material self-assembles into intercalated smectic structure very similar to B6 banana phase. As for B6 phase, this achiral phase is also neither ferroelectric nor antiferroelectric.

Fig. 11. The dependence of the transition temperatures on the number of methylene groups, n, in the flexible alkyl spacer for the CBOnO.lO series.[69] indicates interdigitated smectic A-isotropic transitions, nematic-isotropic transitions, A interdigitated smectic A-interdigitated smectic C transitions, interdigitated smectic A-nematic transitions, O intercalated smectic A-nematic transitions and A intercalated smectic A-intercalated smectic C transitions. The melting points have been omitted for the sake of clarity. SmAa Interdigitated smectic A phase SmCa interdigitated smectic C phase SmAc intercalated smectic A phase SmCca intercalated alternating smectic C phase N nematic I isotropic...

---