Vladimir Kaiser and Èrtomir Stropnik
University of Maribor, Faculty of Chemistry and Chemical Engineering,
Smetanova 17, 2000 Maribor, Slovenia
ABSTRACT
Polymeric membranes were prepared by the wet-phase separation method
from solutions of different contents of polysulfone in N,N-dimethylacetamide;
solutions were cast in different thickness before immersion into the pure
water coagulation bath. Two main processes take place during the formation
of membranes: nucleation and growth of the polymer lean phase with subsequent
solidification of the polymer rich phase, and the formation of channels,
macrovoids and mega-macrovoids. By the first process a cellular structure
is formed whilst the second process connects the cells by opening the space
between them. The degree of interconnectedness is an additional factor
that affects the pure water flux. By changing the cast solution compositions
and/or their cast thickness the interconnectedness of the cells can be
controlled.