Ultrafast Self-Transportation of Multimedia Droplets with a Bioinspired Microspine Array

Abstract

We present a newly developed bioinspired microspine array (BMSA), inspired by the energy gradient in cactus multispines and the liquid film sliding mechanism of rice leaves. Notably, the unmodified BMSA and the modified BMSA (MBMSA) with multiwalled carbon nanotubes (MWCNTs) demonstrate ultrafast directional transport of water and oil droplets, respectively, achieving a transport velocities as high as 102.27 and 237.42 mm/s. These velocities are 1–3 orders of magnitude faster than previously reported values. The structural gradient of the microspines provides the primary driving force for self-transportation, while the MWCNT coating facilitates uniform water film formation, reducing hysteresis resistance. The BMSA demonstrates the capability to separate and collect oil in complex environments and enables efficient antigravity pumping. Additionally, the MBMSA has been utilized in a fog harvesting device (FHD), achieving an impressive collection efficiency of 16,392 mg/h/cm², representing a 61.62% improvement compared to the original device.