The present paper discusses experimental results obtained during the i
nvestigations of electron instabilities in the thin films of poly(3,3'
-phthalidylidene-4,4'-biphenylylene) (PPB). A common feature for all t
hese phenomena is that they are characterized by the dielectric-metal
phase transition which is initiated by external effects of abnormally
low values. The latter include uniaxial pressure, electric field, and
temperature. Possible mechanisms of electron instabilities in thin pol
ymer films are discussed.