Effects of Film-Forming Conditions on Surface Properties and Structures of Diblock Copolymer with Perfluoroalkyl Side Chains

Abstract

Film-forming conditions (cast solvents and film-forming technique: casting or spin-coating) are found to regulate the surface free energy of a diblock copolymer composed of methyl methacrylate and 2-perfluorooctylethyl methacrylate (PMMA-b-PFEMA). The surface properties and structures both in the solid state and in the solution of this polymer were investigated using dynamic contact angle, X-ray photoelectron spectroscopy, X-ray diffraction, reflection-adsorption Fourier transform infrared spectroscopy, dynamic light scattering, and surface pressure measurements. The surface free energy of the PMMA-b-PFEMA film drastically changed from 7.8 to 28.4 mJ/m(2), depending on the film-forming conditions. For the film cast from the micellar solution, the surface free energy is governed by the unimers, localized at the air-solution interface. On the other hand, higher amounts of micelles with the laid perfluoroalkyl side chains were exposed on the surface of the spin-coated film, which yielded a relatively high surface free energy. These findings demonstrated a significant effect of the in-solution molecular association on the surface structures and properties of the solid. In particular, the in-solution unimers played the most important role in lowering the surface free energy of the PMMA-b-PFEMA films.

Molecular Aggregation State of Surface-grafted Poly{2-(perfluorooctyl)ethyl acrylate} Thin Film Analyzed by Grazing Incidence X-ray Diffraction

“…The d-spacing calculated from the peak position was ca. 0.50 nm, which was close to the intermolecular distance between helical chains of PTFE hexagonal (d ¼ 0:49 nm) [38][39][40][41] and was almost the same as the intermolecular distance between R f groups at the side chains of PFA-C 8 spin cast films (d ¼ 0:50 nm). Therefore, it was suggested that the rigid rod-like R f groups underwent hexagonal packing in the brush films of PFA-C 8 with thicknesses of 11 and 43 nm.…”

Synthesis and Characterization of Poly[oxy(ω,ω,ω‐trifluoroalkylsulfonylmethyl)ethylene]s: Effect of Terminal CF3 and CH3 Moieties on the Wettability of the Comb‐Like Polymers

“…These results indicate that the polymer films have a fluorine-rich surface and the carbon-rich interior. [21,22] The larger F/C ratio value at the take-off angle of 308 compared to that at 908 also suggests that the CF 3 terminated polymers are fluorine enriched at the outermost surface. [23] The NEXAFS analysis indicated the alignment of the CF 3 end group and hydrocarbon in the side chain at the surface of the CF 3 -8SE and CF 3 -10SE films.…”

Polystyrene–Polyperfluorooctylethyl acrylate Diblock Copolymers: The Effect of Dilution of the Fluorinated Mesogenic Chains on Bulk and Surface Properties

“…Because of the inherent non-stick behavior fluorinated polymers are candidates as lubricant, wear control, antisoiling and anti(bio)fouling materials. [8][9][10][11][12][13][14][15] In this work, we synthesized welldefined poly(styrene-b-2-perfluorooctylethyl acrylate) copolymers, in order to study how the different chemical composition can affect the bulk and surface properties of the polymeric films. The liquid crystalline copolymer with the shortest fluorinated block was then incorporated into blends with a commercial thermoplastic elastomer SEBS.…”