Biomedical Engineering Reference
In-Depth Information
d
n
3
r
4
n
g
|
3
.
Figure 12.2
(a) Principle of measuring using QCM-D equipment; (b) schematic
explanation of measuring the hydrated viscoelastic factor (Mf).
polymer surfaces during the hydration process (Figure 12.2b). The com-
parison results of Mf values and the traditional factor, i.e., surface free
energy, of five different conventional homopolymer surfaces, poly(methyl
methacrylate) (pMMA), poly(n-butyl methacrylate) (pBMA), poly(isobutyl
methacrylate) (piBMA), poly(methyl acrylate) (pMEA), and poly(2-hydroxy-
ethyl methacrylate) (pHEMA), are shown in Figure 12.3. The surface free
energy shown in this figure was calculated by the following Owens-Wendt
equation based on the result of contact angle measurement by means of
sessile drops of water and methylene iodide:
22
q
g
l
q
g
l
0
@
1
A
þ
2
0
@
1
A
q
g
s
q
g
s
1
þ
cos y
¼
2
(12
:
2)
p
g
lv
p
g
lv
where g
s
, g
s
and g
lv
, indicate the non-polar and polar components of the
surface free energy on the polymer surface, and the surface free energy of
liquid, respectively.
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