Enhanced Photoluminescence, Mesomorphism and Conformation of Liquid‐Crystalline Conjugated Polymers with Terphenyl Mesogen Pendants

Abstract

A variety of LCCPs containing terphenyl pendants based on polyacetylene, polythiophene, poly(p‐phenylene) and a poly(p‐phenylene) copolymer backbone have been synthesized. The effects of the structural variation on their properties, especially their mesomorphism, photoluminescence and secondary structures, were studied systematically. Longer alkoxy spacer favor stronger light emission and better mesomorphism. Disubstituted polyacetylenes show better developed mesomorphic textures, higher quantum yields and better thermal stability than their corresponding monosubstituted analogs. Steric effects and the “jacket‐ effect” from the mesogens cause the bulky terphenyl mesogen pendants to rotate around the main chain and force the main chain to assume a spiral conformation along the main chain in long range.

Synthesis and Spectral Properties of Novel Poly(disubstituted acetylene)s

“…For the preparation of these polymers, typically W or Ta and Nb27, 49–51 (for monomers bearing bulky substituents) catalytic systems are used. It is apparent from the literature that the choice of catalyst has no significant effect on the polymer microstructure 27, 49–52. The mentioned catalytic systems require strictly inert reaction conditions, and all reaction components have to be degassed and dried.…”

Synthesis and self-assembly of fluorene-vinylene alternating copolymers in “Hairy-Rod” architecture: side chain – mediated tuning of conformation, microstructure and photophysical properties

“…Being attached as mesogene side chains, an enhanced photoluminescence was observed due to the resonance energy transfer from the terphenyl pendants to the CP backbone. [43] p-Terphenyl derivatives are also known as helix mimetics (or proteomimetics) of two turns of the myosin light chain kinase α-helix and show functional analogy in binding with high affinity to calmodulin. as helical mimetics of Bad and Bak aromatic protons of the p-terphenyl moiety in all macromonomers appeared in the range 7.5-8.2 ppm.…”

“…The helicogenicity of p-terphenyl, [43] and the discotic, polycyclic aromatic fluorenyl [69] is well known. The role of the side chains was to disfavor the random main chain collapsing into disordered structures, as well as conferring with values around 70-100 nm ( Figure 5(B)).…”

A new class of nanostructured supramolecular organic semiconductors based on intertwined multi-lamellar co-assemblies in π-conjugated liquid-crystalline side-chain polymers

“…Up to now, few examples of such macromolecular architectures have been considered for the exploitation of their charge transport properties and, to the best of our knowledge, no charge-carrier mobility has been evidenced. [36][37][38][39][40] In addition, associated with judicious choices of the electro-active components (donor and acceptor), these well-ordered morphologies offer the possibility of forming separate conduction pathways for charge carriers by playing on their antagonistic chemical nature.…”