Mesogens metal-containing

One of the earlier contributions to the revival of metal-containing liquid crystal systems was the synthesis of the ort, ti-metallated palladium complexes of mesogenic azobenzenes 91, 92 by Ghedini and co-workers, which represented the first systematic attempt to coordinate metals to known liquid-crystal systems. 

Other examples of functional organogel systems include for instance mesogenic derivatives of cyclohexyl bis-amide 23 which form novel liquid crystaline materials with nematic liquids [66], and the tetraoctadecylammonium bromide (like 3) and the metal-containing gluconamides 12 which were able to gelate monomers as styrene and methacrylates and were used to prepare nanoporOus membranes and for polymer imprinting [67,20]. 

When the mesogen moiety is included into the main chain of the polymer, the obtained macromolecule contains inherently rigid units, which usually result in remarkable mechanical properties and thermal stability. Fibers made by these polymers compete with the best ceramic fibers and are far superior to metal fibers [83]. They therefore are ideal candidates as reinforcements for polymer-based composites. However, these materials often have a poor miscibility and adhesion to other polymeric substrates, limiting the range of their applications. This problem basically arises from weak intermolecular interactions either within the liquid-crystalline polymer itself or with the matrix of the composite. Strong ionic... 

The generally rigid, extended nature of metal polyynes is also evident in their tendency to form lyotropic liquid crystalline phases " " (see also Chapter 12.05 on the topic of organometallic mesogens). Homometallic polymers, as well as mixed metal systems, that contain Pt, Ni, and Pd, have all been shown to exhibit liquid... 

Thermotropic liquid crystalline polymers containing P-diketonato groups 11 give inter-chain complexation of the diketonato groups with Cu(II) and Ni(II) [27]. ESR indicates that square-planar coordination is present in the case of Cu(II), orientated parallel to the fiber axis. Too high a metal content suppresses the mesogenic properties owing to the insolubility and reduced mobility of the... 

If a mesogenic monomer is copolymerized with a nonmesogenic monomer, the mesophase is observed above a minimum concentration of the mesogenic monomer. For example, neither poly (methyl meth-acrylate)-co-[6-[4 -(4"-cyanophenylazo)-phenoxy]hexyl methacrylate]) DP 35, pdi =1.35) nor poly (methyl methacry late)-co-[6-[4 -(4"-n-butoxyphenoxycarbonyl)-phenoxy]hexyl methacrylate] DP 69, pdi =1.12) (Scheme 36) prepared by metal-loporphyrin-initiated copolymerizations and containing 18-20 mol% of the mesogenic monomer exhibit the SmA mesophase of the corresponding SCLCPs [90]. 

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