Plasma polymerization of 2-isopropenyl-2-oxazoline: Improvement of the coating stability by co-polymerization with 1-octene

Thin films were deposited by plasma co-polymerization of 2-isopropenyl-2-oxazoline and 1-octene, varying the total monomers flow rate and the 1-octene percentage in the mixture. The coatings wettability was evaluated by water contact angle measurements, while their stability was investigated by immersion in Phosphate Buffer Saline at 37 °C. The chemical characterization of the coatings, performed by means of Attenuated Total Reflectance Fourier Transform Infrared spectroscopy and by reaction with poly(acrylic acid), assessed a partial retention of the reactive oxazoline ring, as already observed for plasma polymerization of several oxazoline monomers alone. However, the addition of 1-octene had significant effects on the coating stability and on the surface availability of reactive oxazoline rings. Compared to those obtained by plasma polymerization of 2-isopropenyl-2-oxazoline alone, this coatings exhibited higher stability in aqueous environments but lower reactivity towards carboxylic acid groups.