Time-resolved GISAXS and cryo-microscopy characterization of block copolymer membrane formation
AuthorsMarques, Debora S.
Dorin, Rachel Mika
Wiesner, Ulrich B.
Smilgies, Detlef Matthias
Behzad, Ali Reza
Nunes, Suzana Pereira
KAUST DepartmentPhysical Sciences and Engineering (PSE) Division
Materials Science and Engineering Program
Imaging and Characterization Core Lab
Biological and Environmental Sciences and Engineering (BESE) Division
Environmental Science and Engineering Program
Water Desalination and Reuse Research Center (WDRC)
Advanced Nanofabrication, Imaging and Characterization Core Lab
Advanced Membranes and Porous Materials Research Center
Chemical and Biological Engineering Program
Nanostructured Polymeric Membrane Lab
Permanent link to this recordhttp://hdl.handle.net/10754/563422
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AbstractTime-resolved grazing-incidence small-angle X-ray scattering (GISAXS) and cryo-microscopy were used for the first time to understand the pore evolution by copolymer assembly, leading to the formation of isoporous membranes with exceptional porosity and regularity. The formation of copolymer micelle strings in solution (in DMF/DOX/THF and DMF/DOX) was confirmed by cryo field emission scanning electron microscopy (cryo-FESEM) with a distance of 72 nm between centers of micelles placed in different strings. SAXS measurement of block copolymer solutions in DMF/DOX indicated hexagonal assembly with micelle-to-micelle distance of 84-87 nm for 14-20 wt% copolymer solutions. GISAXS in-plane peaks were detected, revealing order close to hexagonal. The d-spacing corresponding to the first peak in this case was 100-130 nm (lattice constant 115-150 nm) for 17 wt% copolymer solutions evaporating up to 100 s. Time-resolved cryo-FESEM showed the formation of incipient pores on the film surface after 4 s copolymer solution casting with distances between void centers of 125 nm. © 2014 Elsevier Ltd. All rights reserved.
SponsorsWe thank Yibei Gu, Cornell Materials Science, for assistance with the GISAXS measurements at CHESS. CHESS is supported by the National Science Foundation. The authors at Cornell were supported by the National Institutes of Health and General Medical Sciences via NSF award DMR-0936384. SAXS measurements were carried out at the light source DORIS III at DESY, a member of the Helmholtz Association (HGF). We further thank the National Science Foundation (DMR-1104773) for financial support.