Highly strong bio-inspired ZnO/PDMS superhydrophobic surface with drag reduction and antibacterial properties

Maintaining the long-term stability of water repellency and antifouling remains a challenge. This study presents the fabrication of a solid sharkskin-inspired surface exhibiting superhydrophobic and antifouling properties by polydimethylsiloxane (PDMS) and zinc oxide (ZnO) nanostructures through the simple microcasting and hydrothermal methods. The ZnO grown under optimal reaction parameters showed a remarkable contact angle of 151°, signifying the emergence of superhydrophobicity. Furthermore, the ZnO/PDMS sharkskin surface was found to reduce drag by up to 12.2%. Notably, the bacterial adhesion was decreased on the sharkskin-like PDMS surface with ZnO nanostructures by 96.5% compared to smooth PDMS. This resulted from the combined antifouling effects of ZnO photocatalytic property and the microstructure-induced hydrophobicity. Additionally, the ZnO nanostructures demonstrated exceptional mechanical stability and robustness.