Surface Studies of Polymers with a Well-Defined Segmental Length by ToF-SIMS and XPS. Relationship between the Surface Chemical Composition and Segmental Length

Two series of sequential polymers were synthesized by polymerization of 1, n -dibromoalkane ( n = 4, 6, 8, 10, 12, 14, and 18) with 4,4‘-(hexafluoroisopropylidene)diphenol (6FBA) and bisphenol A (BA). The flexible aliphatic segment length changes from 4 to 21 Å corresponding to 4−18 CH 2 groups. The influence of the flexible aliphatic segment length on the surface composition of BA and 6FBA sequential polymers was investigated by XPS and ToF-SIMS. The O 1s/C 1s peak ratios of the BA polymers indicated that the flexible segment was enriched on the BA polymer surface when the number of the CH 2 groups was larger than 14 (the length of the flexible segment ∼17 Å). The F 1s/C 1s peak ratios of the 6FBA polymers showed that the length of the flexible segment on the surface was the same as the bulk. The ratios between the intensities of the characteristic peaks of the flexible and rigid segments displayed a linear dependence on the surface flexible segment length determined by XPS.