Two different groups of polyethersulfone (PES) membrane have been fabricated using the phase inversion method containing different concentrations of polyvinylpyrrolidone (PVP) as additives. This was to optimize the concentration of the PES polymer and PVP additive in order to produce a membrane with high performance in terms of permeability. The optimized membranes have been further characterized, with the pore-size and pore-size distribution, contact angle, zeta potential and surface roughness measured. It was found that addition of PVP to solution strongly enhances the permeability of the membrane to a specific point as a consequence of the increasing hydrophilicity of the membrane. At high casting solution concentrations the permeability was observed to decrease. This may be due to a high concentration of casting solution resulting in a very dense layer on the membrane surface attenuating the membrane permeability. The influence of PVP on the mechanical properties of PES membrane has been investigated. AFM analysis of surface roughness showed no clear correlation between the measured surface roughness and PVP concentration. (C) 2011 Elsevier B.V. All rights reserved.