Deposition of fluorocarbon thin films on outer and inner surfaces of stainless steel mini-tubes by pulsed plasma polymerization for stents

作者：Nelea V; Holvoet S; Turgeon S; Mantovani D^*

来源：Journal of Physics D: Applied Physics , 2009, 42(22): 225208.

DOI：10.1088/0022-3727/42/22/225208

We report for the first time the deposition of fluorocarbon thin films on outer and inner surfaces of millimetric sized diameter stainless steel mini-tubes by radiofrequency pulsed plasma polymerization for coronary stent applications. The deposition was performed under a glow discharge with a mixture of hexafluorethylene (C(2)F(6)) and hydrogen in a post-discharge configuration with substrates kept at floating potential or continuously biased with a negative voltage of up to 1000V. Film composition, structure, uniformity and covering efficiency on outer and inner surfaces along the mini-tubes were characterized by scanning electron microscopy, Fourier-transformed infrared spectroscopy, x-ray photoelectron spectroscopy and atomic force microscopy. At floating potential, a coating of fluorocarbon (CF(x)) was deposited varying in chemical composition and thickness along the mini-tube axis. The application of a -400V bias voltage led to outer surfaces with a fluorocarbon coating uniform in thickness and homogeneous in composition, along the full length of the mini-tube (10 mm). Despite the application of a negative bias, the covering efficiency for the inner surface was lower compared with the outer surface, with fluorocarbon films homogeneous in both composition and thickness until half length of the mini-tube (5 mm) but thickness decreasing afterwards. Strategies for amelioration of the latter limitation are proposed.

• 出版日期2009-11-21