In this work, atomic force microscopy (AFM) analysis and application of the image processing technique on scanning
electron microscope microphotographs were employed to investigate the performance of polysulfone (PSf) hollow-fiber
membranes treated with hypochlorite and hot water in relation to composition of bore fluid used during spinning of
hollow-fiber membranes. Fiber spinning dope containing PSf/poly vinyl pyrrolidone/N-methyl-2-pyrrolidone (NMP) in a
mass ratio of 15/5/80 were used for production of two types of hollow fibers via the dry-jet wet spinning process.
A mixture of NMP and water in a 1/1 ratio, as well as distilled water alone, were used as bore fluids. The membranes
were treated using 95C water and sodium hypochlorite 4% (w/v). Structurally superior membranes were produced with
the mixed bore fluid. In addition, these membranes exhibited higher permeation in comparison to membranes made
using other bore fluid. Hypochlorite treatment resulted in an increase in surface roughness of the membranes, and was
found to be also responsible for the increase in the average membrane pore size and water flux. The hypochloritetreated membrane produced using NMP/water as bore fluid exhibited a higher rate of flux than those produced using
distilled water. It was also found that treatment with 95C water affected both type of membranes. However, the effect
of this treatment on the membrane produced with mixed bore fluid was more pronounced. Linear regression was used
to establish the correlations between mean surface roughness parameters and hydraulic permeability. AFM analysis
strongly supported the consistency of the measured values of water flux.