Twisted topological solitons and dislocations in a polymer crystal

Topological defects and dislocations in strongly anisotropic crystals consisting of parallel molecular chains are investigated. Our study is focused on the defects in crystalline polyethelyne, which are formed by trans- verse displacements of chain molecules ~mutual substitutions and interlacings of adjacent molecular chains in the polymer crystal!. It is shown that some of these defects called ''twisted topological solitons'' can propagate with a stationary profile and velocity. To describe the dynamics of these solitons, a model that accounts for the three components of the molecular displacements is suggested. Linear topological defects—dislocations—that incorporate the bending of molecular chains in the crystal are also studied.