الفهرس 
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Abstract
This work is concerned with investigation of the influence of electric potential on hollow fiber
(HF) membrane surface characteristics including; morphology, topography, mechanical
properties, volumetric porosity and also chemical composition, where electric potential was
applied on conductive Polysulfone hollow fiber membranes through electrolytic solution.
The electrochemical modification cell was designed and consists of two electrodes, one is a
stainless steel cathode and the other is a graphite anode and electrolytic solution of sodium
acetate with concentration 0.1M. Two different mediums were used, alkaline and acidic
mediums. Different electric potentialfrom 2 to 10 V were applied to the HF membrane surface
and the time duration from 30 min to 120 min. Current density ranges from 0.006 to1.27
mA/mm2
for alkaline medium and from 0.006 to 1.04 mA/mm2
for acidic medium.
The results showed that higher electric potential above 2.5 V are aggressive to the HF membrane
surface and cracks were observed and 2.5 V modifications showed the best results. Contractions
of all HF membrane dimensions were also appeared with a maximum decrease at 5 and 7.5 V
which confirmed by SEM investigations.
EDX analysis revealed an alternating in the chemical composition of HF membrane surface,
where new ions of sodium are appeared with high mass percent of 2.5 % in an acidic medium
after 30 min modification and about 0.84% in the alkaline medium after 60minmodification.
Modulus of elasticity increased by about 5% and break stress increased by about 9% in alkaline
medium. In acidic medium, break strain enhanced about 20 % and break stress increased about
2%. Also, a change in membrane surface roughness was observed. With increasing electric
potential applied on the HF membrane surface, the surface roughness was increased and
confirmed with AFM results.
No significant change in volumetric membrane porosity. The highest porosity was 75.95 % after
30 min of modification, while the lowest porosity was 73.83 % after 90 min in alkaline medium.
While, in acidic medium, the highest porosity was 76.84 % after 30 min of modification, while
the lowest porosity was 71.74 % after 60 min