Zhu Ping, Xu Zheng, Xu Xiaoyu, Wang Dazhi, Wang Xiaodong, Yan Ying, Wang Liding
Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, China.
Key Laboratory for Precision and Non-Traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian 116085, China.
Micromachines (Basel). 2019 Oct 28;10(11):728. doi: 10.3390/mi10110728.
The dispensing resolution of high-viscosity liquid is essential for adhesive micro-bonding. In comparison with the injection technique, the transfer printing method appears to be promising. Herein, an analytical model was developed to describe the dynamic mechanism of squeezing-and-deforming a viscous droplet between plates in a transfer printing process: as the distance between plates decreases, the main constituents of contact force between the droplet and substrate can be divided into three stages: surface tension force, surface tension force and viscous force, and viscous force. According to the above analysis, the transfer printing method was built up to dispense high-viscosity adhesives, which replaced the geometric parameters, utilized the critical contact force to monitor the adhesive droplet status, and served as the criterion to trigger the liquid-bridge stretching stage. With a home-made device and a simple needle-stamp, the minimum dispensed amount of 0.05 nL (93.93 Pa·s) was achieved. Moreover, both the volume and the contact area of adhesive droplet on the substrate were approximately linear to the critical contact force. The revealed mechanism and proposed method have great potential in micro-assembly and other applications of viscous microfluidics.
高粘度液体的点胶分辨率对于粘性微键合至关重要。与注射技术相比，转移印刷方法似乎很有前景。在此，建立了一个分析模型来描述转移印刷过程中粘性液滴在板间挤压和变形的动力学机制：随着板间距离减小，液滴与基板间接触力的主要成分可分为三个阶段：表面张力、表面张力和粘性力、粘性力。根据上述分析，建立了用于点胶高粘度粘合剂的转移印刷方法，该方法取代了几何参数，利用临界接触力监测粘合剂液滴状态，并作为触发液桥拉伸阶段的标准。使用自制装置和简单的针压印，实现了0.05 nL（93.93 Pa·s）的最小点胶量。此外，基板上粘合剂液滴的体积和接触面积与临界接触力大致呈线性关系。所揭示的机制和提出的方法在微组装和粘性微流体的其他应用中具有巨大潜力。
