Surface modification of poly(propylene carbonate) by oxygen ion implantation

Poly(propylene carbonate) (PPC) was implanted by oxygen ion with energy of 40 keV. The influence of experimental parameters was investigated by varying ion fluence from 1 × 1012 to 1 × 1015 ions/cm2. XPS, SEM, surface roughness, wettability, hardness, and modulus were employed to investigate structure and properties of the as-implanted PPC samples. Eight chemical groups, i.e., carbon, CH, COC, CO, OCO, CO, , and groups were observed on surfaces of the as-implanted samples. The species and relative intensities of the chemical groups changed with increasing ion fluence. SEM images displayed that irradiation damage was related strongly with ion fluence. Both surface-recovering and shrunken behavior were observed on surface of the PPC sample implanted with fluence of 1 × 1015 ions/cm2. As increasing ion fluence, the surface roughness of the as-implanted PPC samples increased firstly, reached the maximum value of 159 nm, and finally decreased down the minimum value. The water droplet contact angle of the as-implanted PPC samples changed gradually with fluence, and reached the minimum value of 70° with fluence of 1 × 1015 ions/cm2. The hardness and modulus of the as-implanted PPC samples increased with increasing ion fluence, and reached their corresponding maximum values with fluence of 1 × 1015 ions/cm2. The experimental results revealed that oxygen ion fluence closely affected surface chemical group, morphology, surface roughness, wettability, and mechanical properties of the as-implanted PPC samples.