Designs and recent progress of “pitcher plant effect” inspired ultra-slippery surfaces: A review

The ultra-slippery surface with exceptional slipperiness shows great potential in the fields of liquid food packaging and biomedicine. Although the superhydrophobic surface inspired and created by the "lotus leaf effect" has succeeded in contributing to a high contact angle and widespread applications, its unstable structure, inadequate durability, and reduced hydrophobicity for fluids with high viscosity or poor fluidity are significant drawbacks, which has seriously frustrated the feasible utilization of "lotus leaf effect" induced superhydrophobic surface. To overcome these key bottlenecks, "slippery liquid-infused porous surfaces (SLIPS)" based on the "pitcher plant effect" have emerged at the right moment beyond the superhydrophobic surface, offering excellent performance for fluids with high viscosity, low surface energy, and poor fluidity, as well as low contact angle lag, outstanding self-repairing ability, and high pressure stability. This review first concludes three typical design standards of SLIPS based on the fundamental design principles, followed by summarizing 12 different thermodynamic configurations and 5 kinds of SLIPS failure, which has not yet been well analyzed. Furthermore, the most recent progress on the latest preparation process of SLIPS based on the above principles is also reviewed, and the key effects of substrate structure types, modification characteristics, and lubricants on the functional stability of SLIPS are comprehensively analyzed. The cutting-edge SLIPS prototypes inspired by "pitcher plant effect" principles as well as their promising applications in various great potential fields demonstrating that the green, efficient, stable, easy-to-prepare, and multifunctional materials will play an indispensable role in designing smart and practical SLIPS.