Effect of Electron Repelling and Electron Attracting Groups on the Electrical Conductivity and Thermoelctric Power of some Ethylenes and Butadienes

Conductivity and thermoelectric power of some ethylenes and butadienes have been examined, with the aim of investigating the possible effect of attaching electron repelling or electron attracting groups either to one end of the molecule (as in case of ethylenes) or to the opposite ends (as in case of butadienes). In case of ethylenes, it has been found that both the type and magnitude of the conductivity and thermoelectric power are sensitive to the character of the attaching groups, but the activation energy for conducitivity remains constant (1.4 eV). On the other hand, butadienes (which are douple ethylenes) do not seem to be much affected by the groups, and the activation energy remains close to 0.71 eV, while the thermoelectric power at given temperature remains positive and practically unchanged in magnitude. It would appear possible to control the type of conductivity in ethylenes, electron repelling groups leading to p-type while electron attracting groups leading to n-type conduction.