Ultra-slippery coated surfaces processed by picosecond laser

In nature, Nepenthes pitcher plants inspire corrosion-resistant material design due to their ultra-low-friction surfaces that enable rapid droplet sliding. This study employs picosecond laser treatment and chemical modification to fabricate slippery aluminum surfaces. Key parameters—single pulse energy (SPE), scanning speed/pulse count, and channels/dimple spacing—are systematically analyzed for their effects on contact angle (CA) and surface morphology. For line-processed samples, increased scanning speed reduces line width, depth, and CA, while higher energy enhances all three parameters. Larger line spacing correlates with smaller CA. In dimple processing, more pulses and higher energy increase point diameter, depth, and CA, whereas smaller point spacing yields larger CA. Optimal parameters are 450 μJ energy, 5000 pulses, and 50/100 μm spacing for point processing, and 50 μm spacing, 100 mm/s speed, and 450 μJ for channels processing. A 50 μm dimple-spacing sample achieves 3.448 mm/s sliding velocity after silicone oil immersion. Corrosion tests in acidic, alkaline, and salt solutions reveal slippery aluminum (SLIP-Al) outperforms pristine aluminum (Ps-Al), superhydrophilic aluminum (SHI-Al), and superhydrophobic aluminum (SHB-Al) counterparts. Through polarization curve tests, it is found that the SLIP-Al exhibits the lowest corrosion tendency and the slowest corrosion rate, and its corrosion resistance is approximately 580 times higher than that of Ps-Al. This work highlights applications in biomedicine, marine engineering, and defense.