Nanostructuring of polymethylpentene by plasma and heat treatment for improved biocompatibility

This work is focused on the characterization of the surface properties of PMP (poly-4-methyl-1-pentene) subjected to plasma treatment and thermal annealing. The changes of the surface polarity and the surface free energy, the surface morphology and roughness were studied using electrokinetic analysis, goniometry, AFM, XPS and RBS methods. Ablation of PMP surface layers was determined by gravimetry. The influence of heating on the surface morphology of the plasma treated PMP and its wettability and stability was studied too. The adhesion and proliferation of vascular smooth muscle cells (VSMC) on the plasma treated polymer was investigated too. The plasma treatment causes only minor changes in the surface morphology but it leads to significant mass loss and wettability changes. As expected, the ablated polymer mass increases with the increasing plasma power and exposure time. The plasma treatment increases oxygen concentration on the PMP surface, with the oxygen concentration decreasing towards to the polymer bulk. The thermal annealing results in only minor changes in the PMP surface morphology but it accelerates the aging of the polymer surface and leads to a decline in the oxygen concentration on the polymer surface. The plasma treatment improves cell adhesion and proliferation on the PMP's surface significantly.