a) b - École Polytechnique de Montréal

Since it is difficult to isolate the position of PANI in a 5 component blend system, a ternary
blend of HDPE/PVDF/PANI, already shown in Figure 4-3b was prepared. The morphology of
this blend, after selective extraction of the PVDF, clearly shows the localization of PVDF at the
interface of HDPE and PANI which is a result of the very high spreading coefficient of PVDF
over PANI, λPVDF/PANI (7.3 mN/m). These data on the PE/PVDF/PANI blends as well as the
discussion related to the other ternary and quaternary blend systems above would tend to confirm
the ordering of phases in the quinary system as HDPE|PS|PMMA|PVDF|PANI as was predicted
from Harkins spreading theory.
Although detecting the position of each phase in a five-component onion structure by
microscopy techniques is very difficult, the morphology of 50/10/20/10/10
HDPE/PMMA/PS/PVDF/PANI blend after selective extraction of one or several phases is
represented in Figure 4-6. Figure 4-6a depicts the continuous structure of HDPE after extraction
of all other phases. Empty spherical areas observed in the matrix of HDPE represent onion
domains containing various phases. The selective extraction of PS (Figure 4-6b) and PMMA
(Figure 4-6c) phases from the blend verifies them as two layers of an onion. Figure 4-6d shows
the same blend where phases PS and PMMA have been extracted together demonstrating a wider
empty area, indicating the successive situation of PS and PMMA phases. The extracted area in
Figure 4-6d separates two major phases which are the matrix of HDPE and droplet-in-droplet of
PANI-in-PVDF. All of the above confirms the hierarchical ordering of
HDPE|PS|PMMA|PVDF|PANI in the quinary blend.
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