Corrosion resistance improvement for 316L stainless steel coronary artery stents by trimethylsilane plasma nanocoatings

Abstract

To improve their corrosion resistance and thus long-term biocompatibility, 316L stainless steel coronary artery stents were coated with trimethylsilane (TMS) plasma coatings of 20–25 nm in thickness. Both direct current (DC) and radio-frequency (RF) glow discharges were utilized for TMS plasma coatings and additional NH3/O2 plasma treatment to tailor the surface properties. X-ray photoelectron spectroscopy (XPS) was used to characterize the coating surface chemistry. It was found that both DC and RF TMS plasma coatings had Si- and C-rich composition, and the O-and N-contents on the surfaces were substantially increased after NH3/O2 plasma treatment. Surface contact angle measurements showed that DC TMS plasma nanocoating with NH3/O2 plasma treatment generated very hydrophilic surface. The corrosion resistance of TMS plasma coated stents was evaluated through potentiodynamic polarization and electro-chemical impedance spectroscopy (EIS) techniques. The potentiodynamic polarization demonstrated that the TMS plasma coated stents imparted higher corrosion potential and pitting potential, as well as lower corrosion current densities as compared with uncoated controls. The surface morphology of stents before and after potentiodynamic polarization testing was analyzed with scanning electron microscopy, which indicated less corrosion on coated stents than uncoated controls. It was also noted that, from EIS data, the hydrophobic TMS plasma nanocoatings showed stable impedance modulus at 0.1 Hz after 21 day immersion in an electrolyte solution. These results suggest improved corrosion resistance of the 316L stainless steel stents by TMS plasma nanocoatings and great promise in reducing and blocking metallic ions releasing into the bloodstream.

Tailoring the wettability of glass using a double-dielectric barrier discharge reactor

“…The maximum WCA of 106° was achieved at 1.1 v/v%, corresponding to a TMS flow rate of 11.2 mL min −1 . This WCA is higher than or comparable to those achieved by low-pressure, RF plasmas [ 27 , 32 , 33 , 34 ]. Similar results were also previously reported by using atmospheric pressure, kHz power frequency plasma deposition on glass and PET substrates [ 13 , 35 ].…”

The investigation of deposited organic carbon‐silicon films using cyclonic atmospheric pressure plasma polymerization

“…The chemical composition of the films was analyzed using XPS with a monochromatic Al Kα x-ray source on a VG Scientific Microlab 310F system. In order to calculate the electrolyte uptake of polymeric separators, the separators were immersed in the electrolyte solution, excess electrolyte was wiped away gently using tissue paper, and the electrolyte uptake was determined using a specific Equation (3).…”

“…Plasma polymerization is a frequently used technique to deposit carbon-containing thin films. In this technique, the precursor/monomer is introduced into the vacuum chamber and exposed to a plasma discharge created by an electrical power source [1][2][3]. The plasma breaks down the precursor/monomer molecules, producing highly reactive species that then deposit on the substrate to form a thin film.…”

Multifunctional Plasma-Polymerized Film: Toward Better Anticorrosion Property, Enhanced Cellular Growth Ability, and Attenuated Inflammatory and Histological Responses

“…EIS were also performed to obtain further information about the barrier properties and corrosion resistance performance of the plasma-polymerized films. 36 The corresponding Nyquist plots are presented in Figure 3B. 3.3.…”