Superhydrophobic and superlipophilic polypropylene/β-nucleating agent/ethylene-propylene-diene terpolymer thermoplastic vulcanizates films used for self-cleaning and green oil-water separation

Superhydrophobic materials have significant application value in the fields of self-cleaning and oil-water separation. In this work, a β-nucleating agent-modified polypropylene (PP)/ ethylene-propylene-diene terpolymer (EPDM) thermoplastic vulcanizate (TPVs) was fabricated, and a rough surface texture was constructed using metallographic sandpaper as a template. The resulting material exhibited superhydrophobicity, self-cleaning capability, and pressure responsive oil-water separation performance. The results show that after hot-pressing PP/EPDM TPVs with W10 metallographic sandpaper, the surface contact angle of the TPVs increased to 154.3 °, the sliding angle decreased to 3.1 °, and the surface energy decreased to 12.2 mN·m-1, indicating a remarkable improvement in superhydrophobic performance. Furthermore, with the incorporation of a β-nucleating agent into the PP phase of PP/EPDM TPVs, the loose stacking of β-crystal molecular chains facilitated plastic deformation, leading to a further enhancement of surface roughness after sandpaper templating. Consequently, the surface contact angle increased to 157.8 °, the sliding angle decreased to 2.8 °, and the surface energy was reduced to 11.3 mN·m-1. Under both sliding and rolling self-cleaning test modes, the TPVs with β-nucleating agent exhibited excellent self-cleaning behavior. In oil-water separation experiments, the β-nucleating agent-modified superhydrophobic TPVs films demonstrated rapid separation, high selectivity, and pressure-responsive characteristics across various oil-water mixtures. The critical pressure difference between oil and water phases reached as high as 4.10 kPa, and the separation efficiency remained above 95.0 % even under strong suction forces. This work provides new insights into the development of efficient and sustainable materials for oil-water separation and self-cleaning applications.