54 HIGH PERFORMANCE POLYMERS
A pretreatment with oxygen plasma changes the
substrate surfaces from hydrophobic to superhy-
drophilic [82].
The attachment of fibroblasts is better on fibrous
substrates than on flat substrates, and oxygen plasma
pretreatment facilitates the fibroblast attachment in
general. Serum proteins also facilitate the cell attach-
ment on the substrates [81].
Poly(chloro-p-xylylene) is suitable for its use in
implantable, microfabricated devices [83]. It is hydro-
phobic, with a low dielectric constant, and a good
biocompatibility. However, for many bioelectrical
applications, its poorwet adhesion may be a drawback.
Parylene-C and PPX have been functionalized with
a reactive group X, such as CHO or CH
2
NH
2
. With
these materials, long-term ...