Behavior of contact angle on glass plates coated with plasma-polymerized styrene, allylamine and acrylic acid

Styrene, allylamine and acrylic acid were polymerized by plasma polymerization technique under the ninth polymerization condition from 100 W and 50 Pa to 200 W and 150 Pa. We obtained the film-state polymer only under these conditions. The surfaces of plasma-polymerized (pp-) films from styrene, allylamine and acrylic acid were characterized by means of contact angle measurement. The values of contact angle of pp-styrene, pp-allylamine and pp-acrylic acid were widely scattered under the initial stage of nine polymerization conditions. However, these values after 40 days storage under vacuum condition always converged into 87° for pp-styrene, 67° for pp-allylamine and 28° for pp-acrylic acid, respectively. We assumed that this environmental adaptability of contact angle came from the turn over of polar functional groups between polymer surface and bulk.