Handbook of Solvents - George Wypych - ChemTech - Ventech!

10.1 General concept of acid-base interactions 569
RT ln V N
8
6
4
2
0
-2
-4
5 6 7 8 9
Number of carbon atoms
Figure 10.1.7. Relationship between RT ln V N and
number of carbon atoms in n-alkanes. [Adapted, by
permission from M M Chehimi, E Pigois-Landureau,
M Delamar, J F Watts, S N Jenkins, E M Gibson, Bull.
Soc. Chim. Fr., 9(2) 137-44 (1992).]
v C=O ,cm -1
1745
1735
1725
15 25 35 45 55
γ d
L
Figure 10.1.9. Carbonyl stretching frequency vs. dispersion
contribution to surface tension of solvent. [Adapted,
by permission from M M Chehimi,
E Pigois-Landureau, M Delamar, J F Watts,
S N Jenkins, E M Gibson, Bull. Soc. Chim. Fr., 129(2)
137-44 (1992).]
χ
-0.04
-0.08
-0.12
-0.16
1.76 1.8 1.84
1000/T, K
1.88 1.92
-1
Figure 10.1.8. Flory interaction parameter vs. inverse
temperature for polyamide. [Adapted, by permission,
from L Bonifaci, G Cavalca, D Frezzotti, E Malaguti,
G P Ravanetti, Polymer, 33(20), 4343-6 (1992).]
XPS analysis combined with analysis
by atomic force microscopy, AFM, determines
differences in the surface distribution
of deposited PMMA on the surface of
polypyrrole depending on the type of solvent
used (Figure 10.1.6). 6 AFM, in this experiment,
permitted the estimation of the
surface roughness of polypyrrole. When
PMMA was deposited from
tetrahydrofuran, a poor solvent, it assumed
a surface roughness equivalent to that of
polypyrrole. Whereas PMMA, when deposited
from a good solvent - CHCl 3, 6
developed a smooth surface. The above examples
show the importance of solvents in
coating morphology.
Figure 10.1.7 shows the correlation
between the number of carbon atoms in
n-alkanes and the net retention volume of
solvent using IGC measurements. 8 Such a
correlation must be established to calculate the acid-base interaction’s contribution to the
free energy of desorption, ΔG AB, as pointed out in discussion of equations [10.1.5] and
[10.1.6]. Figure 10.1.8 shows that the Flory interaction parameter (measured by IGC) increases
as the temperature increases.