skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Kinetics of Phase Transition from Lamellar to Hexagonally Packed Cylinders for a Triblock Copolymer in a Selective Solvent

Abstract

We examined the kinetics of the transformation from the lamellar (LAM) to the hexagonally packed cylinder (HEX) phase for the triblock copolymer, polystyrene-b-poly (ethylene-co-butylene)-b-polystyrene (SEBS) in dibutyl phthalate (DBP), a selective solvent for polystyrene (PS), using time-resolved small-angle X-ray scattering (SAXS). We observe the HEX phase with the EB block in the cores at a lower temperature than that observed for the LAM phase due to the solvent selectivity of DBP for the PS block. Analysis of the SAXS data for a deep temperature quench well below the LAM-HEX transition shows that the transformation occurs in a one-step process. We calculate the scattering using a geometric model of rippled layers with adjacent layers totally out of phase during the transformation. The agreement of the calculations with the data further supports the continuous transformation mechanism from the LAM to HEX for a deep quench. In contrast, for a shallow quench close to the order-order transition, we find agreement with a two-step nucleation and growth mechanism.

Authors:
; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
959889
Report Number(s):
BNL-82875-2009-JA
TRN: US201016%%1033
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Macromolecules; Journal Volume: 40
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; COPOLYMERS; KINETICS; NUCLEATION; PHTHALATES; POLYSTYRENE; SCATTERING; SOLVENTS; TRANSFORMATIONS; PHASE TRANSFORMATIONS; QUENCHING; national synchrotron light source

Citation Formats

Liu,Y., Li, M., Bansil, R., and Steinhart, M. Kinetics of Phase Transition from Lamellar to Hexagonally Packed Cylinders for a Triblock Copolymer in a Selective Solvent. United States: N. p., 2007. Web. doi:10.1021/ma071192m.
Liu,Y., Li, M., Bansil, R., & Steinhart, M. Kinetics of Phase Transition from Lamellar to Hexagonally Packed Cylinders for a Triblock Copolymer in a Selective Solvent. United States. doi:10.1021/ma071192m.
Liu,Y., Li, M., Bansil, R., and Steinhart, M. Mon . "Kinetics of Phase Transition from Lamellar to Hexagonally Packed Cylinders for a Triblock Copolymer in a Selective Solvent". United States. doi:10.1021/ma071192m.
@article{osti_959889,
title = {Kinetics of Phase Transition from Lamellar to Hexagonally Packed Cylinders for a Triblock Copolymer in a Selective Solvent},
author = {Liu,Y. and Li, M. and Bansil, R. and Steinhart, M.},
abstractNote = {We examined the kinetics of the transformation from the lamellar (LAM) to the hexagonally packed cylinder (HEX) phase for the triblock copolymer, polystyrene-b-poly (ethylene-co-butylene)-b-polystyrene (SEBS) in dibutyl phthalate (DBP), a selective solvent for polystyrene (PS), using time-resolved small-angle X-ray scattering (SAXS). We observe the HEX phase with the EB block in the cores at a lower temperature than that observed for the LAM phase due to the solvent selectivity of DBP for the PS block. Analysis of the SAXS data for a deep temperature quench well below the LAM-HEX transition shows that the transformation occurs in a one-step process. We calculate the scattering using a geometric model of rippled layers with adjacent layers totally out of phase during the transformation. The agreement of the calculations with the data further supports the continuous transformation mechanism from the LAM to HEX for a deep quench. In contrast, for a shallow quench close to the order-order transition, we find agreement with a two-step nucleation and growth mechanism.},
doi = {10.1021/ma071192m},
journal = {Macromolecules},
number = ,
volume = 40,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}