Biomedical Engineering Reference
In-Depth Information
high-temperature peaks (above 600°C) of CO desorption are likely
generated by decomposition of ester, hydroxyl, and carbonyl groups.
A more careful analysis of thermal decomposition of functional
external layers should take into account the possible transformation
of the oxygen-containing groups on diamond surface under heating.
For example, a partial decomposition of anhydride groups can
convert them into lactones and carbonyls [46].
25
CO
2
+
20
S-1
15
10
B-1
K-2
5
A-2
0
CO
+
K-2
25
20
400
600
800
1000
T,
o
C
S-1
15
B-1
K-2
10
5
A-2
0
200
400
600
800
1000
TEMPERATURE,
o
C
+
Figure 6.4
Temperature profiles of ion fragments CO
(
m
/
z
= 28) and
+
CO
= 44) in TDMS spectra of UDD samples of different
origin. The insert shows the decomposition of real CO-profile
(corrected to the contribution of the fragment CO
+
from CO
(
m
/
z
)
2
into the separate Gaussian peaks for UDD K-2.
There is a correlation between the profiles of CO desorption
from different samples and their IR spectra (see Fig. 6.2): the
higher the wave number of CO band near 1800 cm
-1
, the lower
the temperature of decomposition of the corresponding surface
compounds with CO emission. The TDMS method is more sensitive
than the IR spectroscopy to reveal the structural features of the
functional surface coatings of nanodiamond, as illustrated by the
deep difference in the profiles of thermal evolution of CO from the
