Researchers from SSW, Xerox Research Centre of Canada and Chengdu Green Energy and Green Manufacturing Technology R&D Center developed a TOF-SIMS approach to determine the degree of cross-linking on the surface and its variations in nanoscale depths of organic materials. The proposed that ion intensity ratio (ρ) between C6H¯ and C4H¯ can be used to assess the degree of cross-linking of spin-coated PMMA films cross-linked using a surface-sensitive cross-linking technique (hyperthermal hydrogen projectile bombardment). The degree of cross-linking of the PMMA films was depth profiled using a C60+ sputter beam. As shown in the following figure the cross-linking depth for PMMA film cross-linked for 10, 100 and 500 s is 3, 15 and 39 nm, respectively. The results are published in Rapid Communications in Mass Spectrometry 2017, 31, 281–288.
Surface Science Western 
