Defects in polydiacetylene single crystals. II. Dislocations in pTS

The structure of single crystals of a substituted diacetylene polymer (pTS) has been investigated by using transmission electron microscopy. It has been found that edge dislocations with Burgers vector parallel to the chain direction are present at a density of up to 1013 m−2. It is suggested that the dislocations may be present first of all in the monomer crystals and become locked into the monomer structure during polymerization. It has been found that the dislocations have a tendency to line up in rows perpendicular to the chain direction and when the density of the dislocations in a row is sufficiently high a small−angle grain boundary can be formed. A possible structure for the dislocations on a molecular level is suggested and the effect of the presence of the dislocations upon the polymerization behavior, mechanical properties, and electric properties is discussed.