Tethered Hydrophilic Polymers Layers On A Polyamide Surface

Modification of the hydrophilicity of a polyamide surface with tethered poly(acrylic acid), poly(vinylsulfonic acid), or poly(2-hydroxyethyl methacrylate) was accomplished by atmospheric pressure plasma surface activation, followed by free radical graft polymerization with vinyl monomers. Surface activation was more effective with He relative to H-2 plasma leading to thicker grafted polymer layers of higher surface density. The thickness and surface roughness of the tethered layers were up to similar to 9.7nm and similar to 3.6 nm, respectively. Upon surface modification, the free energy of hydration decreased (25-51%) and the polar component of the surface energy increased (by a factor of 3.0-6.5); the above indicating increased hydrophilicity of the modified surface which also correlated with the tethered polymer layer thickness and surface roughness. The present study suggests that surface hydrophilicity tuning is feasible through the combination of surface chemistry, plasma surface treatment, and graft polymerization conditions. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46843.