We have recently developed a novel and simple approach based on aqueous solutions of block copolymer micelles for the construction of WFs with wettability ranging from the superhydrophobic to the superamphiphobic regime. That is, the copolymers were initially dispersed into water to yield a micelle solution with the insoluble fluorinated block serving as the micellar core and the water soluble block as the micellar corona. The polyethylene terephthalate (PET) or cotton WFs were then dipped into a copolymer micelle solution and then naturally dried at room temperature before they were cured at high temperature to yield WFs with various degrees of liquid repellency. Further investigation on the mechanism for the formation of either super hydrophobic or superamphiphobic WFs using this aqueous process would facilitate the commercial applications of these water-based coatings. In this contribution, polyethylene terephthalate (PET) films with different liquid repellencies based on copolymer aqueous micelle solutions were prepared via previously reported process, and AFM and XPS techniques were respectively employed to evaluate the morphology and chemical composition of the copolymer-coated PET films. The dependence of water and oil contact angles of PET films on the concentrations of the copolymer micelle solution were evaluated and further employed for the prediction different liquid repellencies of PET WFs. The mechanism for the formation of the superhydrophobic WFs or superamphiphobic WFs was also proposed.