EFFECTS OF SINUSOIDAL ELECTROPHORETIC FIELD ON CHAIN MACROMOLECULES IN A HETEROGENEOUS MEDIUM: STRUCTURE AND DYNAMICS BY A HYBRID COMPUTER SIMULATION

Abstract

Using a hybrid simulation method, structural and dynamic response properties of chain macromolecules are studied in a heterogeneous gel matrix in presence of an electrophoretic field E(t) = Eb + Es sin (2π ft), where Eb is the static field and Es is the amplitude of sinusoidal field of frequency f. We find that the oscillating field enhances the macromolecular mobility at Es > Eb while it becomes ineffective at Es < Eb, consistent with the experimental work of Masubuchi et al. Enhanced segmental and global movement of molecules at Es > Eb leads to interesting effects such as (i) a significant decrease in molecular clustering, (ii) reduced radius of gyration, and (iii) its linear response to Eb. Power law behavior of molecular motion, i.e., the variation rms displacement (R) with the time steps (t), R ∝ tν, is sensitive to temperature, molecular weight, and field.