Chemistry Reference
In-Depth Information
concentrations for oleyl alcohol (Figure 5) is probably due to the solvent
action.
8
10
(a)
(b)
10 Hz
25Hz
4
5
15 Hz
20 Hz
30Hz
25 Hz
0
0
0.1
1.0 10.0 100.0
Concentration, mg/m
1
10
2
2
Concentration, mg/m
8
(c)
4
30Hz
25Hz
20Hz
0
0.1
1.0 10.0
Concentration, mg/m
2
Fig. 5.
Relative damping coefficients of oleyl alcohol (a), oleic acid (b) and Em-
karox (c) vs. surfactant concentration
The damping coefficient curves for Emkarox films exhibit two peaks: a
narrow one at low concentrations of about 0.5 mg m
-2
and a "plateau"-like
maximum in the concentration range from about 2-3 mg m
-2
to 6-7 mg m
-2
.
The curves are similar in shape to that reported by Scott and Stephens
(1971) for a film of soluble polymers. The first part of the damping coeffi-
cient curves with the first narrow maximum seems to be similar to the
damping curves for monolayers of oleic acid and oleyl alcohol. Probably,
polymer molecules at small concentrations unfolded and lay on the water
surface interacting with water due to their hydrophilic monomer groups, so
that a polymer film at this stage can to some respect be analogous to films
formed by ordinary surface-active molecules. At higher concentrations the
polymer chains increase the number of loops and tails and the molecules
