ToF-SIMS characterization of molecular ions from Fomblin Z-DOL on Ag substrates

There is great difficulty to obtain molecular ions from the lubricant actually as films on magnetic recording disks. With the assistance of Ag cationization, quasi-molecular ions of (Ag+M)+ from Fomblin Z-DOL cast on Ag substrate were successfully observed on the positive time-of-flight secondary ion mass spectrometry (ToF-SIMS) spectra. Considering the mass interference between oligomers, detailed distributions of molecular weight (Mn) and monomer ratio (m/n) could be extracted. The average values of Mn and m/n obtained by ToF-SIMS are in good agreement with other conventional technique such as nuclear magnetic resonance spectroscopy (NMR).