Mechanisms of Metal Additive-Induced Ordering During SNIPS Membrane Formation
Isoporous membranes can be fabricated by combining self-assembly with nonsolvent induced phase separation (SNIPS) using an amphiphilic block copolymer like polystyrene- b -poly(4-vinylpyridine) (SV). Poly(4-vinylpyridine) (V) is known to complex with metal salts, which are hypothesized to stabilize solution ordering and preserve structure during casting. We explored how the molar ratio of metal additive to the poly(4-vinylpyridine) block affected the final membrane morphology via scanning electron microscopy (SEM). Dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), and in situ grazing-incidence SAXS were used to track changes in solution ordering and chain conformation as a function of the molar ratio of the additive to the V block. Additives induced aggregation, promoted the formation of more compact conformations in solution, and facilitated micelle ordering onto lattices at optimal ratios. These experimental results were supported by random phase approximation calculations, which helped explain how the thermodynamic order–disorder transition shifts with additive binding strength. Stronger additive–polymer interactions reduced the block copolymer volume fraction required for ordering in solution, allowing ordered domains to form at lower polymer concentrations.
Authors
- Matthew N. Davenport (ORCID: https://orcid.org/0000-0002-5828-5366)
- Benjamin J. Pedretti (ORCID: https://orcid.org/0000-0003-2461-822X)
- Mostafa Nassr (ORCID: https://orcid.org/0000-0001-7364-1413)
- Matthew R. Landsman (ORCID: https://orcid.org/0000-0002-4803-1645)
- Joan F. Brennecke (ORCID: https://orcid.org/0000-0002-7935-2134)
- Nathaniel A. Lynd (ORCID: https://orcid.org/0000-0003-3010-5068)
- Louise Kuehster (ORCID: https://orcid.org/0000-0002-0730-204X)
- Gregory M. Su (ORCID: https://orcid.org/0000-0001-7495-8041)
- Venkat Ganesan (ORCID: https://orcid.org/0000-0003-3899-5843)
- Timothy Quah (ORCID: https://orcid.org/0000-0003-4982-7589)
- Glenn H. Fredrickson (ORCID: https://orcid.org/0000-0002-6716-9017)
- Guillaume Freychet (ORCID: https://orcid.org/0000-0001-8406-798X)
- Benny D. Freeman (ORCID: https://orcid.org/0000-0003-2779-7788)
- Noah P. Wamble (ORCID: https://orcid.org/0000-0003-0769-727X)
- Lynn E. Katz
- Paul Irving (ORCID: https://orcid.org/0000-0002-3957-3565)
- Eric Schaible
Institutions
- Lawrence Berkeley National Laboratory (US)
- University of California, Santa Barbara (US)
- Brookhaven National Laboratory (US)
- Commissariat à l'Énergie Atomique et aux Énergies Alternatives (FR)
- Stanford Synchrotron Radiation Lightsource (US)
- Shanghai Xiandai Architectural Design (CN)
- Laboratoire d'Électronique des Technologies de l'Information (FR)
- Advanced Light Source
- National Synchrotron Light Source II
- The University of Texas at Austin (US)
- Université Grenoble Alpes (FR)
Publication Details
- Journal
- Macromolecules
- Published
- 2026-06-30
- DOI
- https://doi.org/10.1021/acs.macromol.6c00832
- Primary Topic
- Origins and Evolution of Life
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Basic Energy Sciences
- Workforce Development for Teachers and Scientists
- Advanced Light Source