基于柔性模板曲率调控的毛细液桥组装新方法

The highly controllable assembly direction and rate of functional building blocks provide capillary liquid bridge assembly methods with unique advantages in preparing multi-dimensional micro-structures with controllable size and morphology, which have potential applications in the production of micro and liano electronic devices with novel optical, electrical, and magnetic characteristics. However, in order to control the assembly direction of functional building blocks, this kind of methods often relies on templates that are prepared by photolithography and require hydrophobic modification on the sides, making the process complicated and costly. To address this issue, through numerical simulation and theoretical analysis, we first point out that the function of templates is to regulate the apparent contact angle of the liq-uid bridge through pinning, thereby affecting the assembly direction of functional building blocks. Furthermore. according to the mechanism of curvature to manipulate the apparent contact angle of a droplet, we provide a new method for controlling assembly direction via simple bending and deformation of flexible templates without chemical modification and processing. We verify the feasibility of the proposed method through the two-dimensional latticc 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 simply controlling the bending direction and degree of the polydimethylsiloxane (PDMS) template, the assembly direction of functional building blocks is highly affccted by the curvature of the template and an annular structure with adjustable width is successfully assembled. This work proposes 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.