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Janus Liquid-Crystalline Multipedes

A recent molecular design, Janus liquid-crystalline molecular materials in the form of segmented structures that contain two different types of mesogenic units has recently been reported [108,109]. Janus materials favor different types of mesophase structure, grafted onto the same scaffold, to create giant molecules that contain different hemispheres ( Janus refers to materials with two faces, such as lluorocarbon/hydrocarbon or hydro-philic/hydrophobic, etc., for example Janus amphiphilic dendrimers have been reported [110-114]). [Pg.51]

The complementary materials 52 and 53, based on a central scaffold made up of pentaerythritol and tris(hydroxymethyl)aminomethane units linked together, where one unit carries three cyanobiphenyl (CB) (smectic preferring), see Fig. 61, and the other three chiral phenyl benzoate (PB) (chiral nematic preferring) mesogenic moieties, see Fig. 62, or vice-versa were investigated [115], see Fig. 63. [Pg.51]

Both Janus compounds, 52 and 53, were isolated as single compounds in a glassy state at room temperature. The predicted and experimental isotopic distribution for the mass ion overlay each other identically confirming the purity of the material and demonstrating the utility of Maldi-fo/ in the determination of structure in supermolecular systems. [Pg.52]

In contrast, compound 53 exhibits only one enantiotropic transition by DSC, which occurs between a chiral nematic phase and the isotropic liquid, in [Pg.52]

Comparison of the phase behavior of compounds 52 and 53 shows clearly that the overall topology of the molecule in respect to the inner core (i.e., which hemisphere carries what mesogen) plays a significant role in determining the type of mesophase formed, since in both cases the number of mesogens of each type and the core are the same and simply by placing them in different hemispheres changes the mesophase exhibited. [Pg.53]


See other pages where Janus Liquid-Crystalline Multipedes is mentioned: [Pg.50]    [Pg.50]   


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