Surface characterization of hydrophilic coating obtained by low‐pressure CH4O2 plasma treatment on a polypropylene film

The use of surface treatments at industrial level is generalized as they allow obtaining a wide variety of properties such as soft in the touch, hydrophilic behavior, and biocompatibility. The use of low‐pressure plasma techniques with organic gases or organic mixtures is an easy way to obtain surface coatings very small in depth through plasma‐polymerization processes that can be assimilated to a plasma‐enhanced chemical vapor deposition (PECVD) process. In this work, we have carried out a plasma‐polymerization process on a polypropylene (PP) film to obtain a hydrophilic coating. To obtain this, the film surface has been treated on a low‐pressure plasma reactor with a methane–oxygen mixture gas with a volume ratio of 80 : 20, respectively. The chemistry changes in the outermost layers of the deposited coating have been investigated with X‐ray photoelectron spectroscopy (XPS). The different processes that take part as a consequence of the interaction between the plasma gas species and the PP film surface mainly drive to the deposition of an organic layer, which is functionalized with oxygen‐based species as XPS study reveals.