Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5181586 | Polymer | 2014 | 6 Pages |
Time-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 72Â 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 84-87Â nm for 14-20Â 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 100-130Â nm (lattice constant 115-150Â nm) for 17Â wt% copolymer solutions evaporating up to 100Â s. Time-resolved cryo-FESEM showed the formation of incipient pores on the film surface after 4Â s copolymer solution casting with distances between void centers of 125Â nm.
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