The Long Alkyl Side Chains On The Surface Structure Of Fluorinated Methyl Acrylate Block Copolymers Constructed

It is challenging to fabricate stable ?uorinated polymer surfaces with excellent water and oil repellent properties as well as low ?uorine content. On the basis of our previous work about surface properties and surface structures of poly(butyl methacrylate)–poly(perfluorooctylethyl methacrylate ) diblock copolymers, a series of poly(butyl methacrylate)-b-poly(octadecyl methacrylate)-b-poly(perfluorooctyl ethyl methacrylate)(PBMA-b-PODMA-b-PFMA) and poly(butyl methacrylate) -b-poly(lauryl methacrylate)-b-poly(perfluorooctylethyl methacrylate) (PBMA-b -PLMA-b-PFMA) were synthesized by atom transfer radical polymerization for the first time. In order to find the correlation of surface structure and the chain architecture of block copolymer, the influence of methacrylate with long side alkyl chain on the surface properties and surface structure of ?uorinated poly(butyl methacrylate) triblock polymers was investigated using contact angle measurement, X-ray photoelectron spectroscopy (XPS), attenuated total re?ectance spectra of infrared (ATR-IR), X-ray diffraction (XRD) , differential scanning calorimetry ( DSC), dynamic light scattering (DLS), surface tension and sum frequency generation (SFG) vibrational spectroscopy. Some conclusions were obtained as follows.(1) When the units of the PFMA were below 3 in poly(butyl methacrylate) -b-poly(octadecyl methacrylate)-b-poly(2-perfluorooctylethyl methacrylate) (PBMA₁₆₄-b-PODMA_m-b-PFMA_n), the stability of surface properties were enhanced with increasing length of the PODMA. The decrease of the water and oil contact angle on PBMA₁₆₄-b-PODMA₅₂-b-PFMA_1.43 films after immersed in 30℃water were 4.7°and 7.6°, respectively. But those on PBMA164-b-PFMA0.98 film surface were 12.5°and 20.2°, respectively.(2) When the units of the PFMA were below 3 in poly(butyl methacrylate) -b-poly(octadecyl methacrylate) -b-poly(2-perfluorooctyl ethyl methacrylate ) (PBMA ₁₆₄-b-PODMA_m-b-PFMA_n), the enrichment extent of fluorine on the film surface was increased with increasing the length of the PODMA block, which indicated that crystallization could drive migration of the perfluoroalkyl segment to the surface. But when the units of the PFMA was about 7, there was no correlation between the enrichment extent of fluorine and the length of PODMA. The PFMA block and the PODMA block might form mixed-crystallization, which reduced the migration of the perfluoroalkyl segment to the surface. (3) The enrichment extent of fluorine on the film surface and the surface stability of PBMA₁₆₄-b-PODMA₅₂-b-PFMA_n decreased with increasing the length of the PFMA block. The decrease in the water and oil contact angle on PBMA₁₆₄-b-PODMA₅₂-PFMA_1.43 after immersed in 30℃water were 4.7°and 7.6°, respectively. But those on PBMA₁₆₄-b-PODMA₅₂-b-PFMA_8.5 were 12.5°and 20.2°, respectively.(4) The enrichment extent of fluorine on the surface of PBMA₁₆₄-b-PLMA_m- b-PFMAn film was much lower than that of PBMA164-b- PLMA_m-b-PFMA_n films.(5) The enrichment extent of fluorine and the layered structure of the fluorinated side chains on the annealed film surface of PBMA₁₆₄-b-PODMA₁₀-b-PFMA_n was enhanced greatly. Accordingly, the film surface became more stable with increasing length of the PFMA.