Biomedical Engineering Reference
In-Depth Information
0.4
0.2
0.0
0
10
20
30
Surface Energy (mJ/m
2
)
Figure 4.4
Distribution plot of total surface energy and its
components for HA powder under study. Circle: dispersive part
of surface energy; triangle: acid-base part of surface energy; and
square: total surface energy
The specific acid-base free energy distributions for applied selected
probes reflect the ratio of structural components of the donor-
acceptor character present at the HA solid/gas interface (
Figure 4.5
).
The broadest distribution was found for acetonitrile ranging from
-11.8 kJ/mol up to 15.0 kJ/mol specific (acid-base) free energy, and
the narrowest one was for dichloromethane ranging from -10.8 to
2.3 kJ/mol. The majority of the polar character surface constituents
in the energy range from -10.6 to 12.8 kJ/mol.
Figure 4.5
shows the
results of free energy profiles for selected probes with different polarity.
It can be seen from the obtained free energy coverage dependencies
that the highest reactivity non-polar sites at 0% coverage are of
approximately seven-fold higher energy content (15 kJ/mol) in
comparison to dichloromethane (2 kJ/mol).
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