Pit formation on poly(methyl methacrylate) due to ablation induced by individual slow highly charged ion impact

We report the formation of nano-sized pits on poly(methyl methacrylate) after exposure to slow highly charged ion beams. The pits are formed on the polymer surface as a direct result of individual ion impacts. Intermittent contact mode atomic-force microscopy was employed to study the size evolution of the pits in dependence of potential and kinetic energies of the incident ions. A potential energy threshold value of approximately 7 keV was found for pit formation. Above this value an increase in potential energy results in an increasing pit volume, while the pit shape can be tuned by varying the kinetic energy.