a) b - École Polytechnique de Montréal

One question that should be addressed is whether the addition of a PS-co-PMMA interfacial
modifier would be expected to theoretically affect the hierarchical order in these blend systems.
Table 4-3 shows a very low value of interfacial tension of γPS/PMMA=1.1 mN/m. If after addition
of copolymer, γPS/PMMA decreases to the lowest possible value close to zero, all ternary blends
comprised of both PS and PMMA in the blend still show positive spreading coefficient values.
These results imply that the positive values of λPS/PMMA in HDPE|PS|PMMA, λPMMA/PVDF in
PS|PMMA|PVDF, and λPMMA/PANI in PS|PMMA|PANI result in three complete wetting cases
with the same order of phases as before the addition of copolymer.
4.4.6 The Effect of the Number of Components of Multi-Percolated
Structures on Conductivity
In this section the effect of the number of the components in multi-percolated structures on the
conductivity, where PANI phase situated as the innermost phase, is investigated as a function of
volume fraction of PANI (Figure 4-14).
The percolation threshold for a conductive material is the concentration at which the first
connected pathway of conductive polymer forms in the blend. Conductivity data thus provides a
tool as powerful as solvent gravimetry to determine percolation thresholds for a conductive
substance. In a blend containing conductive material can be used for both conductivity and
continuity. It implies that the concentration at which the first connected pathway of conductive
polymer in the blend forms, both conductivity and continuity values sharply increase resulting in
percolation threshold. Hence, conductivity percolation threshold corresponds to continuity
percolation threshold of sample. In an onion morphology with the PANI phase located at the core
of a dispersed phase with low connectivity, the conductivity would be expected to be low. Figure
4-14 shows samples with multi-percolated structures constituting various numbers of
components. The concentration of each sample is represented in Table 4-5.
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