In modern society, we need to recycle the widely used plastics so that its related solid waste can be reduced. In this study, we use recycled polypropylene (rPP) to fabricate curved super-hydrophobic surfaces greenly by a water-dissolved filler method. Surface cavities on rPP are formed by salt fillers which can be readily rinsed off and reused. Cavity sizes are created by the filler grain sizes of levels A (<25 μm), B (25–53 μm), C (53–74 μm), and D (74–104 μm), respectively. The results show that the contact angles are 152.8° ± 0.5°, 151.0° ± 1.2°, 150.6° ± 0.6°, 147.2° ± 2.4° for the surfaces made by grain size levels A, B, C, and D, respectively. The corresponding slide angles by levels A, B, and C are 9.0° ± 0.9°, 10.8° ± 0.7°, and 47.3° ± 7.5°; but no SA for level D because the water droplets pin to the fabricated surface, showing the pedal effect. Hence, the surface made by grain size level A reaches the super-hydrophobic condition of CA > 150° and SA < 10°; whereas, that by grain size level B marginally fulfills the criteria. Thus, grain size level A is further used to fabricate curved super-hydrophobic surfaces successfully. In this fabricating process, no harmful chemicals are used while rPP is selected for the purpose. That is, the process is environmentally friendly, low cost, and flexible for various three dimensional surface shapes.
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