Mesogens lateral attachment

Zhou QF, Li HM, Feng XD (1988) Synthesis of a new class of side chain liquid crystal polymers— polymers with mesogens laterally attached via shtut linkages to polymer backbones. Mol Cryst Liq Cryst 155 73-82... 

Properties have been determined for a series of block copolymers based on poly[3,3-bis(ethoxymethyl)oxetane] and poly [3,3-bis(methoxymethyl)oxetane]- (9-tetrahydrofuran. The block copolymers had properties suggestive of a thermoplastic elastomer (308). POX was a good main chain for a weU-developed smectic Hquid crystalline state when cyano- or fluorine-substituted biphenyls were used as mesogenic groups attached through a four-methylene spacer (309,310). Other side-chain Hquid crystalline polyoxetanes were observed with a spacer-separated azo moiety (311) and with laterally attached mesogenic groups (312). 

Tschierske developed a variety of molecules containing a p-terphenyl unit as backbone equipped with two terminal decyloxy chains and laterally attached crown ethers of different sizes [51-53]. The synthesis was straightforward starting from methyl-2,5-dibromobenzoate 30 that was coupled with [4-(decyloxy)phenyl]boronic acid 31 in a subsequent Pd°-catalyzed Suzuki reaction. The 2-hydroxymethyl crown ethers 32 were attached in the last step (Scheme 18) to yield mesogenic 33. 

Fig. 14 Monomers with laterally-attached mesogens featuring fluoro substituents...

A block copolymer consisting of a SCLCP-block of monomer XXVII with a laterally-attached mesogenic unit, and butyl-acrylate, was synthesized using a combination of ROMP and atom transfer radical polymerization (ATRP) (Fig. 16) [81]. 

Fig. 16 Monomers used for block copolymerization containing laterally-attached mesogens...

Recently, a new dendritic system based on a carbosilazane core (Nq = 3, Wb = 2) with laterally attached mesogenic units (Fig. 25) [195-197] was synthesized. Depending on the mesogenic imit, these dendrimers exhibit a single, enantiotropic, room temperature nematic phase (Fig. 25, R = A), or in addition to the N phase, an additional SmC (GO, Gl), or a Col phase (G2) between ca. 50 and 130 °C (Fig. 25, R = B) (Table 8). It is interesting to remark that although the molecular weight of these dendrimers doubles with each... 

Let us note that two homologues of the malonate addends and of the corresponding methanofullerene derivatives described above (Fig. 66) were also prepared with chiral pendant mesogenic groups, laterally attached (Fig. 69). Both the G1 [304] and G2 [57] fullerodendrimers were found to show a chiral nematic phase (Fig. 69, Gl G 26 N 69 1 G2 G 24.3 N 80.61), and are the first Ceo derivatives that possess a chiral mesophase the Gl Geo-free malonate was also mesomorphic (G 20 N 113 I). 

Complementary dendritic hexamers based on a central scaffold made up of linked pentaerythritol and tri(hydroxymethyl)amino methane units have been found to also exhibit liquid-crystalline properties. This star-shaped scaffold was used to create supermolecules containing two different hemispheres, referred to thereafter as Janus supermolecular Hquid crystals (Fig. 76) [323,324]. One of the hemisphere contains three cyanobiphenyl end-groups, whereas the other lobe consists of three chiral phenyl benzoate mesogenic moieties laterally attached. The type of mesophase observed (N ... 

Several polynorborenes with laterally attached mesogens have also been prepared using Mo(CHCMe2Ph)(N-2,6-C6H3-i-Pr2)(0-f-Bu)2 as the initiator in order to determine the effect of molecular weight... 

Figure 3.14. LCEswith laterally attached side-chain mesogens and their deformation behavior. Source Naciri et al., 2003.

H-shaped dimer in which the mesogenic units are laterally attached... 

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