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'-(hexafluoroisopr opylidene)diphenol (6FBA) and bisphenol A (BA). The flexible aliphatic segm ent length changes from 4 to 21 Angstrom corresponding to 4-18 CH2 groups. The influence of the flexible aliphatic segment length on the surface compo sition of BA and 6FBA sequential polymers was investigated by XPS and ToF-S IMS. The O 1s/C 1s peak ratios of the BA polymers indicated that the flexib le 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 similar to 17 Angstrom). The F 1s/C 19 peak ratios of the 6FBA polymers showed that th e length of the flexible segment on the surface was the same as the bulk. T he ratios between the intensities of the characteristic peaks of the flexib le and rigid segments displayed a linear dependence on the surface flexible segment length determined by XPS.