Three Dimensionally Oriented Polyacetylene

Abstract

Changes in the dimensions of oriented polyacetylene under isomerisation and iodine doping are presented. We show that the polymer chains are parallel to the fiber axis. In roll-oriented samples the relative change in dimensions in anisotropic in all three directions and this is atributed to an oredeing of the fibers with respect to the crystalline axes of the polymer. The volume depends libearly on iodine concentration in agreement with a model of inh omogeneous doping where it is assumed that for intermediate iodine concentrations the fibers consist of a fully doped surface layer surrounding the undoped interiour.