Multi-factors bionic lubricant-infused PDMS micropores surface for drag reduction application: design, construction and property

Bionic lubricant-infused surface (LIS), as a novel type of bi-phase material function surface, has garnered widespread attention due to their unique lubrication properties. Inspired by the multi-factors coupling relationship of Nepenthes liquid surface, we begin with microstructures design. The femtosecond laser (the cutting-edge laser technology) is utilized to create precisely micropores on PDMS surface. The process-to-structure design and modulation on micropores distance are accomplished by carefully controlling two key parameters, namely laser scanning speed and scanning pitch. Slippery LISs are constructed by impregnating micropores surfaces with lubricant. Notably, microstructural design and process modulation produce two distinct types of microporous substrates (separated and connected micropores), ultimately yielding two kinds of LISs. For the first time, these two LISs were comprehensively compared through surface wettability, droplet impact, lubricant infusing and drag reduction experiments. In particular, the microfluid technology is firstly utilized to screen microstructures for evaluating the lubricant infusing behaviors. Comprehensive comparison analysis reveals that the connected micropores are more suitable for the preparation and application of drag-reduction LIS. In addition, this study significantly expands the applicability of femtosecond laser surface processing, while establishing a robust theory framework and offering a comprehensive reference for the LISs tailored for drag reduction applications.