Evolution of kink bands and tilt boundaries in block copolymers at large shear strains

Authors
Citation
L. Qiao et Ki. Winey, Evolution of kink bands and tilt boundaries in block copolymers at large shear strains, MACROMOLEC, 33(3), 2000, pp. 851-856
Citations number
19
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
MACROMOLECULES
ISSN journal
00249297 → ACNP
Volume
33
Issue
3
Year of publication
2000
Pages
851 - 856
Database
ISI
SICI code
0024-9297(20000208)33:3<851:EOKBAT>2.0.ZU;2-E
Abstract
The evolution of kink bands and kink band boundaries in a prealigned poly(s tyrene-b-ethylene propylene) lamellar diblock copolymer was investigated by applying steady shear at strains in the range of 1-10 strain units. Bounda ry morphologies were characterized using transmission electron microscopy. As the shear strain increases, both the kink bands and the lamellae within the kink bands rotate continuously toward the shearing direction, leading t o a decrease in the tilt boundary angle and the kink band boundary angle. S imultaneously, the nature of the kink band boundary transforms. The chevron boundaries present at low strains, and thus large tilt angles, become omeg a boundaries as the strain increases to similar to 3 strain units. At highe r strains (similar to 5 strain units), the tilt angle further decreases, an d the omega boundaries start to break, preferentially in the PS microdomain s. Delamination of the PS microdomains was also observed at the highest str ain amplitude (10 strain units), which was associated with the limited exte nt of entanglement across the PS microdomains.