Chemistry Reference
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Figure 6.6
Cell proliferation versus number of days. Reprinted from
Ref. [22], Copyright 2005, with permission from Elsevier.
Diamond-like carbon (DLC) is a promising blood contacting
biomaterial suitable for artificial heart valves, stents, and rotary
blood pumps due to its high inertness and excellent mechanical
properties. Chen et al. prepared DLC carbon films using C
H
2
2
PIII-D and showed that the DLC carbon films possessed good blood
compatibility [23]. In their materials, the carbon atoms existed in
both the sp
3
2
trigonal forms in a predominantly
amorphous state together with 20-40 at.% of hydrogen. AFM
revealed that different C
tetrahedral and sp
:FAr, flow ratios) during
PIII&D produced different surface structures. As shown in Fig. 6.7,
by using a small FC
H
to argon (FC
H
2
2
2
2
H
:FAr ratio, the surface was relatively smooth,
2
2
:FAr ratio gave rise to a rougher surface. They
attributed the difference to the sp
but a higher FC
H
2
2
3
content [23].
X-ray photoelectron spectroscopy showed that the implantation
voltage significantly affected the chemical states of carbon. As
shown in Fig. 6.8, the photoelectron line of C1s peaks measured at
different sputtered depths (series) disclosed that in the deposited
sample (Fig. 6.8a), only carbon was detected in the top 11 nm. From
about 11 nm to 68 nm, the chemical shifts were not significant
indicating that the Ti to C ratio was less than 0.15 and the film
consisted of predominantly carbon. At larger depths, chemical shifts
representative of carbide emerged suggesting the formation of a
graded carbide interface between the carbon film and substrate. As
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