Polymer interface changes in electrophoretic deposition

Abstract

A Monte Carlo computer simulation model for the electrophoretic deposition of polymer chains on a discrete lattice is used to study the polymer density profile, interface growth, and its dependence on field, temperature, and molecular weight. The interface width ( W) decreases W∼ E −1/2 on increasing the field ( E). Width ( W) depends non-monotonically on the temperature ( T): a power-law decay is followed by a power-law increase on raising the temperature. Monotonic decay of the interface width with the molecular weight is possibly a stretched exponential. Conformation and dynamics of a tracer chain is used to probe its characteristics in interface to bulk region. The root mean square (rms) displacement of the center of mass of the tracer chain shows an ultra-slow motion, R∼ t ν ( ν∼0.1–0.01 at E=0.1–1.0) as the driven chain moves deeper from interface to bulk. Longitudinal compression of the radius of gyration ( R g) of the chain increases with the field; transverse components ( R g x , R g y ) are larger than the longitudinal component ( R g z ). The transverse component ( R g x ( y)) becomes oscillatory due to periodic squeezing at high fields as the field competes with the polymer barriers.