Drag reduction and antifouling properties of non-smooth surfaces modified with ZIF-67

Marine equipment and ships operating in complex environments face high drag consumption and severe surface fouling. Non-smooth biomimetic surfaces with specific microstructures work to reduce surface drag and inhibit fouling. In this work, the biological sharkskin shield scale structure was simplified by the idea of segmented independence to construct a bionic non-smooth surface. Single-crystal lithography was used to create a negative template of the silicon substrate. We created a non-smooth bionic structure on the flexible polydimethylsiloxane (PDMS) surface through die casting and molding. Additionally, the bionic non-smooth surface was modified by decorating zeolitic imidazolate framework-67 (ZIF-67) particles to modulate the antifouling properties. Based on tests performed on a self-designed and processed circulating water bath laboratory bench (CWBLB), results showed the non-smooth surface effectively reduced drag by 7.3% compared to that of smooth surface. The contact angle (CA) measurement and anti-bio-adhesion experiment on the surface showed that PDMS surface CAs increased from 109.78° to 140.71°, and Chlorella vulgaris attachment was decreased by 65.3%. The non-smooth bionic surface effectively reduces drag and antifouling, and the effectiveness of the antifouling can be significantly enhanced by augmenting and regulating the particle surface modification method. Our results provide a feasible solution for ship drag reduction and antifouling, which is critical for industrial applications and sustainable development.