Directional fluid spreading on microfluidic chip structured with microwedge array

Abstract

Directional liquid transport has broad engineering applications, and recent efforts have demonstrated the feasibility of rapid and long-distance directional transport using external driving forces, such as light, electricity, magnetism, and mechanical force. However, the externally driven mechanism limits its application in small and intelligent areas. The manufacture of the passive directional flow surfaces remains a significant challenge. In this account, we present a passive microfluidic chip with microwedge grooved channels for improved fluid directional manipulation. Benefiting from the cooperative effect of the asymmetric resistance and capillary driving force, the microwedged channel possesses the reliable functions for long-distance, anti-gravity, and continuous directional fluid transport in a microfluidic chip. To improve these properties, we optimized the structure parameters of the microwedges, resulting in a unidirectional value of up to 7.48. Furthermore, we explored the functions and applications of these microwedge arrays in intelligent and microfluidic systems. By combining different microwedge arrays, we programed that the microfluidic chips were programed with different functions, such as microfluidic logic, liquid gating, and anti-gravity capabilities, with multi-path transportation of an overall length of 537.6 mm. This research provides important guidance on functional surfaces for the design of intelligent integrated microfluidic chips and plays a significant role in promoting practical industrial applications.