Depth profile XPS analysis of polymeric materials by C60 + ion sputtering

When the depth profile of chemical composition is studied with X-ray photoelectron spectroscopy (XPS), the Ar+ ion sputtering method is generally adopted. However, in the case of polymers, chemical composition is destroyed, and so it is impossible to obtain accurate depth profile on polymers. In this research, the depth profile XPS analysis of aliphatic polymers, aromatic polymers, fluorine containing polymers, and natural polymers were conducted with the sputtering source being C60 + ion, and the degree of damage was examined while comparing the results with the case of conventional Ar+ ion. It was found that Ar+ ion induces significant carbonization in all the polymers above-mentioned. Meanwhile, it turned out that C60 + ion causes little damage to most polymers. However, in the case of the non-aromatic polymers containing halogen, hydroxyl, carboxyl, and ether groups in their backbones, the following three damage modes were found: (1) the functional group ratio changes by over ±10%; (2) new functional groups are formed; (3) the above (1) and (2) phenomena occur simultaneously.