Addition of a single chemical functional group to a polymer surface with a mass‐separated low‐energy ion beam

A mass‐separated low‐energy ion beam system was used to deliver pure OH + and NH + to 15nm thick polystyrene films on silicon in ultrahigh vacuum. This was done in an effort to produce specific surface chemical functional groups. X‐ray photoelectron spectroscopy showed that when the bombardment energy of OH + exceeded 10 eV, or the dose was higher than 1 × 10 16 ions cm −2 , a mixture of COH, CCO and CCOOH groups was produced, along with severe damage to the aromatic rings. However, for bombardment at 10 eV with a dose of 1 × 10 16 ions cm −2 , only COH (or COR) groups were found. Similarly, bombardment with NH + at 10 eV and a dose 1 × 10 16 ions cm −2 induced incorporation of a single nitrogen‐containing functionality. The C 1s data indicated that the major chemical functionality on such surfaces in a CNH 2 (or CNHR) group with a minor component of C(NH 2 ) 2 . Hence, surface functionality can indeed be controlled by altering the molecular nature, energy and dose of the bombarding species.