Surface hydrophilic modifications on polypropylene membranes by remote methane/oxygen mixture plasma discharges

The aim of this study was to evaluate the remote effect of low-pressure 13.56 MHz radio-frequency (RF) methane (CH4)/oxygen (O2) mixture plasma on surface modification and its correlation with photoemission of plasma species. We also conducted surface analysis of microporous polypropylene (PP) membranes modified with RF CH4/O2 mixture plasmas. We applied Fourier transform infrared spectroscopy, confocal laser scanning microscopy, and scanning electron microscopy to determine correlations between changes in surface properties and the luminous effect. We showed that the CH4/O2 mixture plasma treatment effectively enhances the surface hydrophilicity and surface free energy of PP membranes in the remote plasma region.