Transmission electron microscopy (TEM) and electron diffraction (ED) are us
ed to study the morphology of a semicrystalline polyolefin diblock copolyme
r polyethylene-b-atactic-polypropylene (PE-b-aPP) and its blend with polyet
hylene homopolymer. By using RuCl3/NaClO as the staining agent, both the co
ntrast between amorphous PP and amorphous PE regions and the contrast betwe
en amorphous PE regions and crystalline PE regions can be obtained. As a re
sult, both the larger lamellar structures due to microphase separation and
the smaller crystalline PE lamellae can be resolved on TEM micrographs. Ele
ctron diffraction coupled with TEM imaging is used to elucidate the orienta
tion of PE crystallites with respect to the interfaces of the microphase se
parated block copolymer lamellar domains. Fast quenching from a microphase
separated melt-state was found to result in confinement of PE crystallizati
on within the microphase separated PE domains of the block copolymer morpho
logy. The orientation of the PE crystallites thus formed was found to be ra
ndom. (C) 2001 Elsevier Science Ltd. All rights reserved.