Environmental Engineering Reference
In-Depth Information
surface energy of the substratum inluenced the adhesion of cells [9]. They showed that
the relationship between the cells adhered to the substratum and its free energy was
not linear (
Figure 2.9
) [45]. This relationship is known as the Baier curve. The curve
shows a minimum value for adhered cells at a critical surface energy of 25 mN/m,
which is a moderately hydrophobic surface. Dexter and co-workers [44] showed that
bioadhesion is less on hydrophobic surfaces with a low surface energy. In contrast
to this observation, Fletcher and Loeb [40] reported that large numbers of bacteria
attached to hydrophobic plastics such as Telon, polyethylene (PE), polystyrene (PS),
and PET, which had little or no surface charge.
80
60
40
20
0
0
10
20
30 40
Surface Energy (mN/m)
50
60
70
80
Figure 2.9
The Baier curve, which shows a correlation between cell adhesion and
surface energy
Becker [46], in his study with bacteria
Pseudomonas sp
., and the diatom
A. coffeaeformis
, reported that PC (33.5 mN/m) provided better adhesion than
other materials such as polytetraluorethylene (PTFE) (19 mN/m), PTFE/perluoro
copolymer (20 mN/m), luorethylene PP (20.5 mN/m), ethylene tetraluorethylene
