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Title: Grain Rotation in Ion-Complexed Symmetric Diblock Copolymer Thin Films under an Electric Field

Abstract

In symmetric polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) diblock copolymer thin films, lithium-PMMA complexes were formed with the addition of lithium chloride (LiCl), significantly increasing both {chi} and dielectric constant. These led to a transition in the kinetic pathway of the orientation of lamellar microdomains under an applied electric field from a disruption and re-formation of the microdomains to a grain rotation mediated by movement of defects. By controlling the number of lithium-PMMA complexes, the microdomain alignment is possibly regulated in PS-b-PMMA copolymer thin films.

Authors:
; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
930170
Report Number(s):
BNL-80828-2008-JA
TRN: US200822%%1218
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Macromolecules; Journal Volume: 39
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; COPOLYMERS; ELECTRIC FIELDS; LITHIUM COMPLEXES; GRAIN ORIENTATION; PERMITTIVITY; ROTATION; THIN FILMS; POLYSTYRENE; PMMA; CRYSTAL DEFECTS; national synchrotron light source

Citation Formats

Wang,J., Leiston-Belanger, J., Sievert, J., and Russell, T. Grain Rotation in Ion-Complexed Symmetric Diblock Copolymer Thin Films under an Electric Field. United States: N. p., 2006. Web. doi:10.1021/ma0614287.
Wang,J., Leiston-Belanger, J., Sievert, J., & Russell, T. Grain Rotation in Ion-Complexed Symmetric Diblock Copolymer Thin Films under an Electric Field. United States. doi:10.1021/ma0614287.
Wang,J., Leiston-Belanger, J., Sievert, J., and Russell, T. Sun . "Grain Rotation in Ion-Complexed Symmetric Diblock Copolymer Thin Films under an Electric Field". United States. doi:10.1021/ma0614287.
@article{osti_930170,
title = {Grain Rotation in Ion-Complexed Symmetric Diblock Copolymer Thin Films under an Electric Field},
author = {Wang,J. and Leiston-Belanger, J. and Sievert, J. and Russell, T.},
abstractNote = {In symmetric polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) diblock copolymer thin films, lithium-PMMA complexes were formed with the addition of lithium chloride (LiCl), significantly increasing both {chi} and dielectric constant. These led to a transition in the kinetic pathway of the orientation of lamellar microdomains under an applied electric field from a disruption and re-formation of the microdomains to a grain rotation mediated by movement of defects. By controlling the number of lithium-PMMA complexes, the microdomain alignment is possibly regulated in PS-b-PMMA copolymer thin films.},
doi = {10.1021/ma0614287},
journal = {Macromolecules},
number = ,
volume = 39,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}
  • No abstract prepared.
  • We examine the behavior of lamellar phases of charged/neutral diblock copolymer thin films containing mobile ions in the presence of an external electric field. We employ self-consistent field theory and focus on the aligning effect of the electric field on the lamellae. Of particular interest are the effects of the mobile ions on the critical field, the value required to reorient the lamellae from the parallel configuration favored by the surface interaction to the perpendicular orientation favored by the field. We find that the critical field depends strongly on whether the neutral or charged species is favored by the substrates.more » In the case in which the neutral species is favored, the addition of charges decreases the critical electric field significantly. The effect is greater when the mobile ions are confined to the charged lamellae. In contrast, when the charged species is favored by the substrate, the addition of mobile ions stabilizes the parallel configuration and thus results in an increase in the critical electric field. The presence of ions in the system introduces a new mixed phase in addition to those reported previously.« less
  • Local control of the domain orientation in diblock copolymer thin films can be obtained by the application of electric fields on micrometer-length scales. Thin films of an asymmetric polystyrene-polymethylmethacrylate diblock copolymer, with cylindrical polymethylmethacrylate microdomains, were spin-coated onto substrates previously patterned with planar electrodes. The substrates, 100-nanometer-thick silicon nitride membranes, allow direct observation of the electrodes and the copolymer domain structure by transmission electron microscopy. The cylinders aligned parallel to the electric field lines for fields exceeding 30 kilovolts per centimeter, after annealing at 250{degrees}C in an inert atmosphere for 24 hours. This technique could find application in nanostructure fabrication.more » 22 refs., 3 figs.« less
  • The chain extension at lamellar interfaces was studied in thin films of symmetric diblock copolymers on gold substrates. The first copolymer consisted of blocks of polystyrene (PS) and poly(2-vinylpyridine) (P2VP), denoted P(S-b-2VP). The second was a diblock copolymer of PS and poly(methyl methacrylate) (PMMA), denoted P(S-b-MMA), on a gold substrate. Using attenuated total reflectance spectroscopy, the refractive indices parallel, n[sub [parallel]], and perpendicular, n[sub [perpendicular]], to the surface of the films were determined. It was found that the total birefringenece, [Delta][sub T] = n[sub [perpendicular]]-n[sub [parallel]], of the as-cast films was positive, indicative of an orientation of the copolymer chainsmore » parallel to the film surface. Upon annealing at 170C, [Delta][sub T] changed sign and attained a limiting value, [approximately][minus]7[times]10[sup [minus]4] for P(S-b-2VP) and [approximately][minus]20[times]10[sup [minus]4] for P(S-b-MMA). It was found that the form birefringence, [Delta][sub F], dominates the intrinsic birefringence, [Delta][sub I], for P(S-b-MMA). On the other hand, [Delta][sub I] was much greater than [Delta][sub F] for P(S-b-2VP). From [Delta][sub I] the extension ratios of the chains at the interface were found to be 1.5-1.6 for both copolymers.« less