Synthesis of ABC-triblock copolymers for light emitting diodes

In this paper we report on the synthesis and characterization of ABC-triblock copolymers poly(N-vinylcarbazole)-block-poly(4-(1-pyrenyl)butyl vinyl ether)-block-poly(2-[4-(2-phenyl-1,3,4-oxdiazolyl)phenyloxy]ethyl vinyl ether) 15. The ABC-triblock copolymers were synthesized by sequential living cationic polymerization of N-vinylcarbazole 11, 4-(1-pyrenyl)butyl vinyl ether 10 and 2-chloroethyl vinyl ether 3. In a second step, the reactive pendant chloro groups of the poly(2-chloroethyl vinyl ether) segment of the block copolymers were substituted with 2-(4-hydroxyphenyl)-5-phenyl-1,3,4-oxadiazole 6 to form fully functionalized ABC'-triblock copolymers. The molecular weight of the block copolymers varied from (M) over bar(n) = 4800 to 14 000. The thermal behavior is discussed with respect to the block copolymer composition and compared with corresponding polymer blends. LED characteristics of a single layer device for one of the block copolymers are presented as an example.