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This content will become publicly available on May 23, 2019

Title: Thickness Limit for Alignment of Block Copolymer Films Using Solvent Vapor Annealing with Shear

The swelling and deswelling of a cross-linked polydimethylsiloxane (PDMS) pad adhered to a block copolymer (BCP) film during solvent vapor annealing (SVA) provides sufficient shear force to produce highly aligned domains over macroscopic dimensions in thin films. Here in this paper, we examine how far this alignment can propagate through the thickness of a BCP film to understand the limits for efficacy of the SVA-S (SVA with shear) process. Films of cylinder-forming polystyrene-block-polyisoprene-block-polystyrene (SIS) ranging from 100 nm to more than 100 μm are examined using the same processing conditions. The SIS surface in contact with the PDMS is always well-aligned, with Herman’s orientation parameter (S) exceeding 0.9 as determined from AFM micrographs, but the bottom surface in contact with the silicon wafer is not aligned for the thickest films. The average orientation through the film thickness was determined by transmission small-angle X-ray scattering (SAXS), with S decreasing gradually with increasing thickness for SIS films thinner than 24 μm, but S remains >0.8. S precipitously decreases for thicker films. A stop-etch-image approach allows the gradient in orientation through the thickness to be elucidated. The integration of this local orientation profile agrees with the average S obtained from SAXS. These resultsmore » demonstrate the effective alignment of supported thick BCP films of order 10 μm, which could be useful for BCP coatings for optical applications.« less
Authors:
 [1] ; ORCiD logo [1] ;  [2] ; ORCiD logo [3] ;  [2] ; ORCiD logo [1]
  1. Univ. of Akron, OH (United States). Dept. of Polymer Engineering
  2. Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source II (NSLS-II)
  3. Brookhaven National Lab. (BNL), Upton, NY (United States). Center for Functional Nanomaterials (CFN)
Publication Date:
Report Number(s):
BNL-205771-2018-JAAM
Journal ID: ISSN 0024-9297
Grant/Contract Number:
SC0012704; 1462284.
Type:
Accepted Manuscript
Journal Name:
Macromolecules
Additional Journal Information:
Journal Volume: 51; Journal Issue: 11; Journal ID: ISSN 0024-9297
Publisher:
American Chemical Society
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1454806