Thin Isoporous Block Copolymer Membranes: It Is All about the Process.
The combination of the self-assembly of amphiphilic block copolymers and the nonsolvent induced phase inversion process offers an efficient way to isoporous integral-asymmetric membranes. In this context we report fast, easily upscalable and material reducing ways to thin self-assembled membranes. Therefore, we succeeded to implement a spray or dip coating step into the membrane formation process of different diblock copolymers like polystyrene-block-poly(4-vinylpyridine), poly(α-methylstyrene)-bock-poly(4-vinylpyridine), and polystyrene-block-poly(iso-propylglycidyl methacrylate). The formation of hexagonal pore structures was possible using a highly diluted one solvent system allowing the reduction of diblock copolymer consumption and therefore the production costs are minimized compared to conventional blade casting approaches. The broad applicability of the process was proven by using different flat and hollow fiber support materials. Furthermore, the membranes made by this new method showed a more than 6-fold increase in water flux compared to conventional polystyrene-block-poly(4-vinylpyridine) membranes with similar pore sizes prepared by blade casting. The membranes could be proven to be stable at transmembrane pressures of 2 bar and showed a pH responsive flux behavior over several cycles.
Helmholtz-Zentrum Geesthacht, Institute of Polymer Research , Max-Planck-Strasse 1, 21502 Geesthacht, Germany.
Janina
J
Hahn
Helmholtz-Zentrum Geesthacht, Institute of Polymer Research , Max-Planck-Strasse 1, 21502 Geesthacht, Germany.
Juliana I
JI
Clodt
Helmholtz-Zentrum Geesthacht, Institute of Polymer Research , Max-Planck-Strasse 1, 21502 Geesthacht, Germany.
Clarissa
C
Abetz
Helmholtz-Zentrum Geesthacht, Institute of Polymer Research , Max-Planck-Strasse 1, 21502 Geesthacht, Germany.
Volkan
V
Filiz
Helmholtz-Zentrum Geesthacht, Institute of Polymer Research , Max-Planck-Strasse 1, 21502 Geesthacht, Germany.|University of Hamburg, Institute of Physical Chemistry , Grindelallee 117, 20146 Hamburg, Germany.
Volker
V
Abetz
block copolymer; dip coating; nanoporous membranes; pH responsive; self-assembly; spray coating