Design for improved adhesion of fluorine-incorporated hydrogenated amorphous carbon on metallic stent: Three-layered structure with controlled surface free energy

Fluorine-Incorporated Amorphous Carbon Coating Inhibits Adhesion of Blood Cells to Biomaterials

“…Neumann et al reported that neutrophils from human whole blood or in BSA solution adhered less to the low surface tension (surface free energy) materials such as fluorocarbon resins. (31) As a-C:H:F coating has a surface free energy lower than 30 mJ/m 2 , (19) the adherence of neutrophils was suppressed in this study. These results demonstrated the anti-inflammatory properties of a-C:H:F coating, showing that a-C:H:F coating can reduce inflammatory risks associated with the implantation of SUS material.…”

“…(20,21) Hasebe et al revealed that the a-C:H:Si/a-SiC:H multi-interlayer decreased the extent of cracking and delamination between the a-C:H:F film and SUS316L stents. (19) The deposition of a-SiC:H film was carried out for 10 min at a tetramethylsilane (TMS, Shin-Etsu Chemical Co., Ltd., Japan) flow rate of 16 sccm at a bias voltage of −2.0 kV for the first interlayer. Subsequently, the deposition of a-C:H:Si film was carried out for 10 min at a bias voltage of −2.0 kV from a mixture of TMS and C 2 H 2 at flow rates of 4 and 65 sccm, respectively.…”

“…(16,17) We also reported that a-C:H:F-coated biomaterials can play a nontoxic mediating role in vivo, (18) and we developed fluorine-incorporated a-C:H (a-C:H:F) coating techniques for vascular interventional devices using radio frequency plasma-enhanced chemical vapor deposition (RF-PECVD). (19) However, the adhesion of leukocytes in relation to a-C:H:F has not yet been elucidated. In this study, therefore, we evaluate not only the adhesion of neutrophils but also the adhesion and activation of platelets on a-C:H:F coating to verify the blood compatibility of the a-C:H:F coating.…”

Effect of TiN/C Microstructure Composite Layer on the Adhesion of FDLC Film onto Silicon Substrate

“…Some methods that are mentioned in these studies include the following: (1) insertion of a transition layer such as SiC layer [12][13][14], chromium nitride film [15,16], and WC-Co layer [17] between the film and substrate (most commonly used method); (2) addition of a buffer layer on the surface finish of the substrate (mostly monometal layers) [18,19]; (3) doping of a third element in the film (or implantation of an ion, such as Si [20,21], N [22][23][24], Ti [25], and Al [21]) to improve the film-substrate binding; and, (4) combination of a buffer layer and ion implantation to increase the film-substrate binding force [9,26]. These techniques decrease the unconformability of the film-substrate boundaries or the stress that is caused by different thermal expansion factors, thereby greatly improving the film-substrate binding force.…”

Fabricating functionally graded films with designed gradient profiles using pulsed laser deposition

“…This is a popular technique to fabricate a film with advanced and/or improved functionality by designing a film with more than one material. For example, interlayer and multilayer techniques [6][7][8][9][10][11] have been used to improve the adhesion strength of diamond-like carbon (DLC) films. As well known, a large internal compressive stress exists in DLC films regardless of the growth technique, and the film starts to peel off from the substrate when this large compressive stress reaches a certain level.…”