Low Surface Energy Characteristics of Mesophase-Forming ABC and ACB Triblock Copolymers with Fluorinated B Blocks

We prepared several triblock copolymers of the A‒B‒C and A–C–B types composed of hydrophobic polystyrene (A), hydrophobic/lipophobic fluorinated polystyrene (B), and hydrophilic PEG-modified polystyrene (C) blocks with greatly varied degrees of polymerization. The resulting surface structure and organization of the polymer films were investigated by measurements of the static contact angle with several interrogating liquids and by X-ray photoelectron spectroscopy at different take-off angles. The contact angle values were also used to evaluate the film surface tensions, following two fundamentally different approaches. The low surface energies found for any of the triblock copolymers were attributed to the pronounced hydrophobicity and lipophobicity of the outermost surface caused by the preferential segregation of the fluorinated block regardless of the distinctly different macromolecular architectures of the triblock copolymers.