Long-distance self-driving method for liquid drop on wetted gradient surfaces

Abstract

The invention discloses a long-distance self-driving method for liquid drop on wetted gradient surfaces. The wetted gradient surfaces comprise uniform silicon oxide stripes and silicon nano-needle structures. Silicon oxide with static contact angles of 15.5 degrees is arranged on hydrophilic regions on the surfaces of wetted gradient solid, the silicon nano-needle structures etched by the aid of deep reactive ions are arranged at the bottoms of the wetted gradient solid, static contact angles of silicon nano-needles are 166.0 degrees, and lag angles of the silicon nano-needles are 3.0 degrees.The long-distance self-driving method has the advantages that the surface wetted gradient ranges of the solid can be greatly expanded and can reach 150 degrees at least, lag phenomena of front and rear contact lines of the liquid drop can be optimized, and the tiny liquid drop with the sizes of 38 mm can be self-driven over long distances; diversified directional self-driving movement paths are designed for the liquid drop, and the long-distance self-driving method is novel in design and is an excellent innovation scheme.

Description

technical field [0001] The invention relates to a microfluidic control system, in particular to a long-distance self-driving method for liquid droplets on a surface with a wetting gradient. Background technique [0002] In microfluidic systems, the directional self-driving of droplets without external force, especially in chemical analysis, biomedicine, etc., has attracted widespread attention at home and abroad. Oriented self-actuation of droplets usually requires external energy (active or passive) to overcome the inherent contact line hysteresis at the solid-liquid interface. The common methods to break the wetting symmetry of solid surface are: chemical gradient, topological gradient, topological gradient, temperature gradient, electromagnetic force, mechanical vibration, pH value induction and the mixture of various methods. Among these methods, wetting gradients on solid surfaces prepared by topology and chemical material inhomogeneity have attracted much attention du...

AI Technical Summary

Problems solved by technology

However, this small wetting gradient range reduces the driving force for liquid droplets to move on the surface of the wetting gradient, limits the moving distance, and cannot meet the higher needs of industry development.

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