Electric field induced surface modification and impermeability enhancement for a polymer film

A compression region was unexpectedly formed in a semiliquid alkyd film during polymerization under a local electric field, and the thin compression region in the cured film was found to be interestingly more impermeable than the other thick areas. Based on optical and SEM observations and electrochemical impedance spectroscopy analysis, a charging process was proposed to interpret the film morphology change. It was further inferred that some of the species from air ionization in the electric field might participate in the polymerization of the film and the electric field could beneficially interfere the micro-defects in the film, both of which helped lower the permeability of the cured film. The study also implies that the electric field modification may be employed to micro-machine a soft surface, enhance the quality of an organic coating, and even control automatons in future.