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This content will become publicly available on October 10, 2018

Title: Gas Transport Selectivity of Ultrathin, Nanoporous, Inorganic Membranes Made from Block Copolymer Templates

Here, we report the fabrication of ultrathin, nanoporous silicon nitride membranes made from templates of regular, nanoscale features in self-assembled block copolymer thin films. The inorganic membranes feature thicknesses less than 50 nm and volume porosities over 30%, with straight-through pores that offer high throughout for gas transport and separation applications. As fabricated, the pores are uniformly around 20 nm in diameter, but they can be controllably and continuously tuned to single-digit nanometer dimensions by atomic layer deposition of conformal coatings. A deviation from expected Knudsen diffusion is revealed for transport characteristics of saturated vapors of organic solvents across the membrane, which becomes more significant for membranes of smaller pores. We attribute this to capillary condensation of saturated vapors within membrane pores, which reduces membrane throughput by over 1 order of magnitude but significantly improves the membrane’s selectivity. Between vapors of acetone and ethyl acetate, we measure selectivities as high as 7:1 at ambient pressure and temperature, 4 times more than the Knudsen selectivity.
Authors:
 [1] ;  [1] ; ORCiD logo [1] ;  [1]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States). Center for Functional Nanomaterials (CFN)
Publication Date:
Report Number(s):
BNL-114436-2017-JA
Journal ID: ISSN 0897-4756; TRN: US1702963
Grant/Contract Number:
SC0012704
Type:
Accepted Manuscript
Journal Name:
Chemistry of Materials
Additional Journal Information:
Journal Volume: 29; Journal Issue: 21; Journal ID: ISSN 0897-4756
Publisher:
American Chemical Society (ACS)
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:
1409499