Surface microphase separation in PDMS-b-PMMA-b-PHFBMA triblock copolymer films

Well-defined poly(dimethylsiloxane)-block-poly(methyl methacrylate)-block-poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) (PDMS-b-PMMA-b-PHFBMA) triblock copolymers were synthesized via atom transfer radical polymerization (ATRP). Surface microphase separation in the PDMS-b-PMMA-b-PHFBMA triblock copolymer films was investigated. The microstructure of the block copolymers was investigated by transmission electron microscopy (TEM) and atomic force microscopy (AFM). Surface composition was studied by X-ray photoelectron spectroscopy (XPS). The chemical composition at the surface was determined by the surface microphase separation in the PDMS-b-PMMA-b-PHFBMA triblock copolymer films. The increase of the PHFBMA content could strengthen the microphase separation behavior in the PDMS-b-PMMA-b-PHFBMA triblock copolymer films and reduce their surface tension. Comparison between the PDMS-b-PMMA-b-PHFBMA triblock copolymers and the PDMS-b-PHFBMA diblock copolymers showed that the introduction of the PMMA segments promote the fluorine segregation onto the surface and decrease the fluorine content in the copolymers with low surface energy.