Droplet/bubble manipulation on a biomimetic material with low-friction

Abstract

Controllable transport of fluids as well as bubbles is the cornerstone of various bioprocesses and microporous technology applications, with a wide range of applications in microfluidics, bioassays, gas transport, and oil-water separation technologies. Although functional modulation of solid surfaces to achieve different surface responses for directional manipulation of microfluidics has been extensively investigated, non-contact bubble/droplet directional manipulation remains a challenge in this field. Here, we report a simple candle soot deposition method to achieve the construction of oil-filled surface nano-roughness, and then achieve the combination of oil-locking performance and photo-thermal response performance on the PDMS surface, and produce a near-infrared light (NIL) response soot nano skeleton oil-filled surfaces (NSNOS), which can be effectively applied to the directional manipulation of droplets and bubbles. Soot nanoparticles act as a backbone to support the SiO₂ shell to provide structural stability, while Fe₃O₄ nanoparticles combine to provide the surface with excellent NIL photothermal response properties. It can be heated up to more than 150 ℃ within 60 S. Precise droplet/bubble orientation manipulation is thus achieved. And through the localized thermal response to near-infrared light, we can realize the control of droplets and bubbles for anti-gravity and anti-buoyancy motions with precise and controllable trajectories. And we believe that this work provides important insights for the development of the smart field of droplet/bubble micro-manipulation and smart field development.