LOCAL DYNAMICS OF POLYMER-CHAIN IN AN EXT ERNAL DIPOLE FIELD

An analytical theory is developed that describes local relaxation prop erties of a freely jointed chain composed of rigid units and oriented by a dipole field. The theory takes into account the bond reactions. T he conformation properties and local mobilities of such system were mo deled by the method of brownian dynamics. The chain segments are orien ted along the field. The order parameter of the segments and the degre e of chain deformation increase with the field amplitude. The rotation al mobility of the chain segments was studied. In contrast to the dyna mic properties of a chain exposed to a strong field of the quadrupole symmetry, both longitudinal and transverse (with respect to the dipole field direction) rotational relaxation times of the chain segments de crease with increasing degree of deformation. The spectrum of relaxati on times of the normal modes of the chain splits into two branches, co rresponding to the longitudinal and transverse motions relative to the direction of the external field. The two branches are characterized b y different dependences of the relaxation times of various scales on t he degree of chain deformation. An analytical theory is presented that satisfactorily describes the dependence of the relaxation time on the dipole field strength obtained in a numerical experiment.