Synthesis and Characterization of Luminescent and Hole Transporting Rod-Coil Polymers

Abstract

Luminescent cyano-substituted distyrylbenzene derivatives were synthesized via Knoevenagel condensation reactions. By using these compounds as initiators, a series of rod-coil polymers were synthesized by the atom transfer radical polymerization of methacrylate containing hole transporting carbazole moiety in high yields except the initiator with dicyanovinyl end groups. Molecular weight up to 37000 and polydispersity indices not exceeding 1.6 were obtained. Photoluminescent spectra revealed the aggregation of the rod parts in the solid state. The rod parts containing fluorinated alkyl groups were further aggregated by the heat treatment. The contact angle measurements suggested the fluoro alkyl groups dominated the film surface in the aggregation process. Microporous films with the open pore diameter of 1.1 or 3.7 µm were fabricated by casting the polymer solution under a moist air flow. Transmission spectrum showed the dip originated from the periodic arrangement of micropores.

Fabrication of Microporous Film and Microspheres Hybrids

“…Highly ordered microporous polymer films with honeycomb structure have been fabricated by a simple nontemplate method utilizing various types of block copolymers [1]- [8]. Although rod-coil type poly(p-phenylene)b-polystyreneor star-shaped polystyrene has been used in a pioneer study [1], other types of block copolymers have been also utilized including T-shape copolymer [5] and amphiphilic block copolymers [7] [8]. It is recognized that the mechanism for the formation of honeycomb structure can be explained by dissipative processes, where controlled condensation and growth of water droplets on the cold surfaces resulting from solvent evaporation of polymer solutions may be used to create a patterned surface.…”

“…Hayakawa et al reported that using a specially designed block copolymer, resulting porous films had highly ordered hierarchical structures over multiple length scales from angstroms to micrometers [6]. Furthermore, the surface aggregation of selective component is expected [5].…”