Optimization of membrane performance by thermal-mechanical stretching process using responses surface methodology (RSM)

Thermal-mechanical stretching process was proposed to modify membrane morphology for enhancing membrane performances. In this study, Response Surface Methodology (RSM) was used to achieve satisfactory responses of lateral flow membrane performances. The factors considered in this study were the stretching elongation (4-22% of the total membrane sample's length), stretching speed (0.04-0.1 mm/s) and stretching temperature (25-75 degrees C). The response variables included the lateral flow membrane performances in terms of porosity, lateral wicking time and protein binding ability. These responses were presented graphically based on the central composite design (CCD) of RSM. Atomic Force Microscope (AFM), Field Emission Scanning Electron Microscopy (FESEM) and statistical analysis showed that all the three stretching factors significantly affected the final membrane structures and performances. The optimum stretching elongation of membrane was found to be at 18% with the stretching rate and temperature of 0.07 mm/s and 35 degrees C respectively. This optimum stretching condition is proven to have high membrane porosity (78.63%), high protein binding ability (4496.5 mu g/cm(3)) and fast lateral wicking rate (579.0 s/4 cm) where deviation between predicted and actual responses fell within 5%. (C) 2008 Elsevier B.V. All rights reserved.