Block copolymer self-assembly - a next generation membrane manufacturing method

K.V. Peinemann, S.P. Nunes, M. Karunakaran, N. Pradeep
KAUST, SA

Keywords: membrane, block copolymer, self-assembly

Summary:

A process is described to manufacture asymmetric pH-responsive nanochannels with very high densities (pore density > 2x1014 pores per m2). Uniform polymeric nanotubes with diameters in the sub 10nm and lengths in the 200 nm range could be created by self-assembly of metal-block copolymer complexes and non-solvent induced phase separation. The influence of different metal ions on the uniformity of the resulting nano-channels was measured and it is shown that the nanotube density and uniformity corresponds with the stability constants for the metal-polymer complexes. The pH response of the polymer nanotubes is the strongest, which has been reported with synthetic pores in the nm range (reversible flux increase of more than 2 orders of magnitude when switching the pH from 2 to 8). The stimuli response and the morphology of the films was studied by advanced electron microscopy methods (e.g. cryo field emission electron microscopy and transmission electron microscopy tomography), SAXS and ultra-/nanofiltration experiments.