New approach to achieving the potentially high conductivity of polydiacetylene

It is postulated that only the surface layers of the structural formations are doped in single crystals of various polydiacetylenes because of the high packing density of their macromolecules and that this is the reason for the low level of conductivity attained in these conjugated polymers. For the purpose of raising the efficacy of the doping process by increasing the surface-to-volume ratio of the polymer, single crystals of the polydiacetylene poly-1,1,6,6-tetraphenylhexadiinediamine (poly-THD) are ground by various methods. A correlation between the particle size of the ground single crystals and their dc conductivity in the doped state is discovered. A record value of the conductivity (3×10 −2 S/cm) for polydiacetylenes, which is more than two orders of magnitude higher than published values (10 −3 –10 −5 S/cm), is achieved.