ELECTRICAL-CONDUCTIVITY OF POLY(BUTADIENE-CO-2-VINYL PYRIDINE) DIBLOCK COPOLYMERS DOPED WITH TCNQ

Diblock copolymers of various compositions consisting of polybutadiene blocks (PB) and poly(2-vinyl pyridine) blocks (P2VP) were prepared by anionic polymerizations. The P2VP block was converted to a polycation and reacted with 7,7,8,8-tetracyanoquinodimethane (TCNQ) while the PB block was left unchanged. Flexible and processible films of these block copolymers with conductivities as high as 10-2 Scm-1 were cast from organic solvents. Conductivity measurements and wide angle X-ray diffraction results confirmed that there is an optimal ratio of TCNQ0 to TCNQ- for which the conductivities are highest. It was found that this ratio was somewhat higher than expected because of the reaction of TCNQ0 adjacent to TCNQ- anion-radicals and with the quaternized and unquaternized pyridine units. Transmission electron microscopy studies revealed the presence of essentially regular phase separation in the solid state of the simple salts of the block copolymers but phase separation in complex salts of the block copolymers was highly irregular. © 1990.