Abstract：The highly controllable assembly direction and rate of functional building blocks render capillary liquid bridge assembly methods have unique advantages in preparing multi-dimensional microstructures with controllable size and morphology, which have potential application in the production of micro and nano electronic devices with novel optical, electrical, and magnetic characteristics. However, in order to control the assembly direction of functional building blocks, this kind of method often relies on templates that are prepared by photolithography and require hydrophobic modification on the sides, making the process complicate and costly. In order to solve the above problem, through numerical simulation and theoretical analysis we firstly points out that the function of template is to regulate the apparent contact angle of the liquid bridge through pinning, thereby affecting the assembly direction of functional building blocks. Furthermore, according to the mechanism of the curvature to manipulate the apparent contact angle of droplet, we provide a new method to control the assembly direction by simple bending and deformation of the flexible template without chemical modification and processing. The feasibility of the provided method is firstly verified through two dimensional Lattice Boltzmann Method (LBM). The simulated results show that the assembly direction of functional building blocks depends on the positive or negative curvature of the flexible template. We also perform a series of experiments to verify the new method. Through simple control of the bending direction and degree of PDMS template, the assembly direction of functional building blocks is highly affected by the curvature of the template and an annular structure with adjustable width is successfully assembled. This work provides a simple and feasible new method for capillary bridge assembly, which can more effectively regulate the assembly of functional building blocks, and provides a new idea for its current applications in micro and nano electronic devices with novel characteristic.
2023, Vol. 44 
