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Title: Lamellae orientation in dynamically sheared diblock copolymer melts

Abstract

Two distinct lamellae orientations have been identified by small angle neutron scattering in dynamically sheared poly(ethylene--propylene)-poly(ethylethylene) diblock copolymer melts. Near the order--disorder transition and at low shear frequencies, the lamellae arrange with unit normal perpendicular to the flow direction and parallel to the velocity gradient direction (parallel lamellae). Higher frequency processing leads to lamellae with unit normal perpendicular to both the flow and velocity gradient directions (perpendicular lamellae). The crossover from low to high frequency behavior occurs at a frequency roughly equal to the inverse of the relaxation time for local domain deformations. At temperatures well below the order-disorder transition, the parallel orientation is obtained at all shearing frequencies. The perpendicular orientation is proposed to arise from shear-induced disordering, followed by reordering in the perpendicular direction due to the effect of vorticity.

Authors:
; ;  [1]
  1. Univ. of Minnesota, Minneapolis, MN (United States)
Publication Date:
OSTI Identifier:
141760
Report Number(s):
CONF-930304-
TRN: 93:003688-1444
Resource Type:
Conference
Resource Relation:
Conference: 205. American Chemical Society national meeting, Denver, CO (United States), 28 Mar - 2 Apr 1993; Other Information: PBD: 1993; Related Information: Is Part Of 205th ACS national meeting; PB: 1951 p.
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; LAMELLAE; ORIENTATION; COPOLYMERS; PHASE STUDIES; POLYETHYLENES; POLYPROPYLENE; ORDER-DISORDER TRANSFORMATIONS

Citation Formats

Koppi, K A, Tirrell, M, and Bates, F S. Lamellae orientation in dynamically sheared diblock copolymer melts. United States: N. p., 1993. Web.
Koppi, K A, Tirrell, M, & Bates, F S. Lamellae orientation in dynamically sheared diblock copolymer melts. United States.
Koppi, K A, Tirrell, M, and Bates, F S. 1993. "Lamellae orientation in dynamically sheared diblock copolymer melts". United States.
@article{osti_141760,
title = {Lamellae orientation in dynamically sheared diblock copolymer melts},
author = {Koppi, K A and Tirrell, M and Bates, F S},
abstractNote = {Two distinct lamellae orientations have been identified by small angle neutron scattering in dynamically sheared poly(ethylene--propylene)-poly(ethylethylene) diblock copolymer melts. Near the order--disorder transition and at low shear frequencies, the lamellae arrange with unit normal perpendicular to the flow direction and parallel to the velocity gradient direction (parallel lamellae). Higher frequency processing leads to lamellae with unit normal perpendicular to both the flow and velocity gradient directions (perpendicular lamellae). The crossover from low to high frequency behavior occurs at a frequency roughly equal to the inverse of the relaxation time for local domain deformations. At temperatures well below the order-disorder transition, the parallel orientation is obtained at all shearing frequencies. The perpendicular orientation is proposed to arise from shear-induced disordering, followed by reordering in the perpendicular direction due to the effect of vorticity.},
doi = {},
url = {https://www.osti.gov/biblio/141760}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1993},
month = {12}
}

Conference:
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