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

•Remote effects of CH4/O2 plasma treatment on polypropylene membrane were studied.•The CH4/O2 plasma improves the wettability of the polypropylene membrane surface.•The species from remote CH4/O2 plasma cause increased surface energy of the membrane.•Remote CH4/O2 plasma is an effective modification method for polypropylene membrane.

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.

Graphical abstractSurface energy examination and optical emission analysis demonstrates the remote effects on PP membranes surface by CH4/O2 mixture plasma polymerization, which increases the surface energy of PP membrane. The present study illustrates the role of remote region in CH4/O2 mixture plasma for PP surface modifications.Figure optionsDownload full-size imageDownload as PowerPoint slide