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Title: Magnetic alignment of block copolymer microdomains by intrinsic chain anisotropy

We examine the role of intrinsic chain susceptibility anisotropy in magnetic field directed self-assembly of a block copolymer using in situ x-ray scattering. Alignment of a lamellar mesophase is observed on cooling across the disorder-order transition with the resulting orientational order inversely proportional to the cooling rate. We discuss the origin of the susceptibility anisotropy, Δ χ, that drives alignment and calculate its magnitude using coarse-grained molecular dynamics to sample conformations of surface-tethered chains, finding Δ χ ≈ 2×10 –8. From field-dependent scattering data, we estimate that grains of ≈ 1.2 μm are present during alignment. Furthermore, these results demonstrate that intrinsic anisotropy is sufficient to support strong field-induced mesophase alignment and suggest a versatile strategy for field control of orientational order in block copolymers.
Authors:
 [1] ;  [2] ;  [1] ;  [1] ;  [1] ;  [1] ;  [3] ;  [3] ;  [2]
  1. Yale Univ., New Haven, CT (United States)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States)
  3. Univ. of Wisconsin, Madison, WI (United States)
Publication Date:
Report Number(s):
BNL-111841-2016-JA
Journal ID: ISSN 0031-9007; PRLTAO; R&D Project: 16077; KC0403020
Grant/Contract Number:
SC00112704; SC0012704
Type:
Accepted Manuscript
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 115; Journal Issue: 25; Journal ID: ISSN 0031-9007
Publisher:
American Physical Society (APS)
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY
OSTI Identifier:
1246786
Alternate Identifier(s):
OSTI ID: 1233966