Abstract
The aim of this study is to enhance the cell attachment on poly(ethylene terephthalate) (PET) and ethylene tetrafluoroethylene (ETFE) by applying atmospheric pressure dielectric electric discharge plasma surface modification. Plasma-modified PET and ETFE show the change in surface energy and also specific functional groups are found to be on the surface via using different working gas. Pure Ar plasma could effectively alter the chemical and physical properties, and especially Ar plasma-treated ETFE shows the large amount of oxygen containing groups on the surface. On the other hand, the increment of C-C/C-H bonds on PET makes it more hydrophobic after Ar/H2 plasma treatment. The nitrogen functional groups are introduced on PET and ETFE via Ar/H2/N2 plasma modification. PET and ETFE modified by Ar/H2/O2 plasma would enhance the surface hydrophilicity due to the increased the surface roughness and the incorporation of oxygen functionalities. In addition to pure surface modification, a layer of poly(ethylene glycol) methyl ether methacrylate (PEGMA) is applied onto PET and ETFE prior to Ar/H2/O2 plasma treatment. Surface characterization confirms that C-O bond is increased due to grafting of PEGMA induced by plasma. Cell adhesion on plasma-treated PET and ETFE under different treating parameter is evaluated by cell culture of NIH 3T3 fibroblast cells. Ar, Ar/H2/N2, and Ar/H2/O2 plasma-treated PET and ETFE surface improve the cell affinity. The increase of surface wettability, roughness, and amino functional groups would be beneficial to cell adhesion. The cell attachment significantly decreases after plasma PEGMA grafted modification. Therefore, the polymers with any structure can be modified by DBD plasma technique to control the cell response.