Diblock and triblock fluorinated copolymers: an ARXPS study

In this contribution we prepared (by TEMPO-mediated radical polymerization) two triblock copolymers (poly(S-b-SF8-b-SP3) and poly(S-b-SP3-b-SF8)) of the A-B-C and A-C-B types composed of hydrophobic styrene (A), hydrophobic/lipophobic fluorinated styrene (B), and hydrophilic PEG-modified styrene (C) polymer blocks with greatly varied degrees of polymerization. A diblock copolymer (poly(S-b-SF8)) was used for comparison. The resulting surface structure and organization of the polymer films were investigated by x-ray photoelectron spectroscopy at different angles (70, 50, and 20 being the angle between the analyzer axis and the specimen normal). Besides the wide scan spectra, detailed spectra for the C 1s, F 1s and O 1s regions and related data are presented and discussed. XPS analysis reveals the preferential surface segregation of the phase-separated fluorinated block regardless of the distinctly different macromolecular architectures of the triblock copolymers.