title: Studies on the effects of the alkyl group on the surface segregation of poly(n-alkyl methacrylate) end-capped 2-perfluorooctylethyl methacrylate films.
abstract: The effects of the alkyl group on the surface segregation of poly(n-alkyl methacrylate) end-capped with various numbers of units of 2-perfluorooctylethyl methacrylate (FMA) (PnAMA-ec-PFMA) were investigated by differential scanning calorimetry, angle-resolved XPS analysis, contact angle measurements, and X-ray diffraction (XRD). The results show that with similar numbers of FMA units at the polymer chain end the extent of fluorine segregation (Q) increased with increasing the number of carbon atoms in the side n-alkyl chains of poly(n-alkyl methacrylate). The surface fluorine content within 5 nm deep of the film of poly(n-octadecyl methacrylate) end-capped with one FMA unit (PODMA(160)-ec-PFMA(1.0)) was 208-fold higher than that of the bulk level. These observed differences in Q values were found due to the aggregate structure of the end-capped polymers in the solution, the flexibility, and the crystallinity of the n-alkyl side chains. When the nonfluorinated block was completely amorphous, the molecular aggregate structure of the end-capped polymers in the solution played an important role in the surface segregation of the fluorinated moieties on the resulting film. However, when the nonfluorinated block was crystalline, crystallinity would enhance greatly the segregation of the fluorinated moieties.
authors.affiliation: Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018, China.
authors.forename: JuPing
authors.initials: J
authors.lastname: Yang
authors.forename: DaXiang
authors.initials: D
authors.lastname: Yuan
authors.forename: Bin
authors.initials: B
authors.lastname: Zhou
authors.forename: Jie
authors.initials: J
authors.lastname: Gao
authors.forename: HuaGang
authors.initials: H
authors.lastname: Ni
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: XinPing
authors.initials: X
authors.lastname: Wang
mesh_terms: D008567:Membranes, Artificial; D011109:Polymethacrylic Acids / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D008567:Membranes, Artificial; D011109:Polymethacrylic Acids