Theory of electric birefringence of long flexible polymer chains with transverse bond dipole moments: Tetrahedral lattice model

We describe the Kerr effect in a strong electric field for a polymer chain having only a transverse component of the dipole moment (type B chain). The theory is based on a rotational-isomeric- state model for: a tetrahedral l attice which was applied previously for chains with a longitudinal componen t of the dipole moment (type A chain). We calculate various conformational properties and orientational parameters as functions of the electric field magnitude. The overall chain behavior in a strong electric field can be des cribed as the orientation of "effective" segments by the applied field. The "effective" segment length increases with the field strength. The field de pendence of the electric birefringence for type B chains is shown to be str onger than that for type A chains with the same dipole moment per monomer u nit. The initial polymer chain rigidity and conformational rearrangements s trongly influence the Kerr effect for any type of dipole moment distributio n.