Facile fabrication of durable and flexible superhydrophobic surface with polydimethylsiloxane and silica nanoparticle coating on a polyethylene terephthalate film by hot-roll lamination

Practical applications of superhydrophobic surfaces have been limited by several disadvantages such as complex fabrication processes, high modification cost, and low mechanical durability. In this study, we present a facile and low-cost fabrication method to make flexible superhydrophobic films by a hot-roll lamination process. The film consists of a hydrophobic polydimethylsiloxane (PDMS) and hydrophobic silica nanoparticle (SNP) com-posite coating layer on a polyethylene terephthalate (PET) film. The coated film displayed excellent super -hydrophobic properties with an apparent water droplet contact angle of 176.3 degrees and a sliding angle of 2.4 degrees. The surface morphology, roughness, and cross-section chemical composition of the coated films were investigated by field emission scanning electron microscopy and confocal laser scanning microscopy. The mechanical durability of the coated films was evaluated using several tests such as scratching with sandpaper, repeated bending deformation, and adhesion tape tests. The fabricated superhydrophobic films still showed superhydrophobic behavior after 20 tape tests. In addition, the fabricated superhydrophobic films exhibited strong mechanical durability, which preserved their very high contact angle >160 degrees and very small sliding angle <10 degrees after a 350 cm abrasion test with 240 grit sandpaper and a pressure of 1.2 kPa. Also, the coated sample exhibited very stable superhydrophobicity after 100 bending cycles due to the elasticity of PDMS. The chemical stability of flexible PDMS/SNP coated PET films was also investigated in acidic, neutral, and alkaline solutions and showed excellent chemical stability in acidic and neutral media in contrast to the alkaline medium. The obtained results demonstrated the outstanding robustness of the fabricated flexible superhydrophobic films that are promising for self-cleaning and water droplet bouncing performance.

Automated summary

A facile and low-cost method was presented to fabricate flexible superhydrophobic films with excellent mechanical durability and chemical stability using a hot-roll lamination process. The films displayed outstanding superhydrophobic properties and maintained high contact angles and low sliding angles even after multiple tests, showcasing promising self-cleaning and water droplet bouncing performance.