On the Growth of Fluorocarbon Thin Films Deposited on Plasma‐Etched 316L Stainless Steel

Plasma fluorocarbon films deposited on 316L stainless steel have shown promising adhesion properties as potential stent coatings. However, further analyses revealed the occurrence of nano‐defects, which led to water infiltration and delamination. Plasma etchings with two different gases, C2F6 and H2, were applied prior to the coating deposition in order to etch the oxide layer of the stainless steel and to create activated sites on the surface to promote the polymerization. Surfaces and thin layers were analyzed by atomic force microscopy, X‐ray photoelectron spectroscopy, time of flight‐secondary ion mass spectrometry, fourier‐transform infra‐red spectroscopy, and near edge X‐ray absorption fine structure to study the film growth mechanism. Hydrogen etchings demonstrated to play a crucial role in the first step of the fluorocarbon growth through the formation of hydroxides at the stainless steel surface, which served as initiator during plasma polymerization. magnified image