模内键合聚合物微流控芯片键合强度分析

Analysis on bonding strength of polymer microfluidic chip by in-mold bonding

利用分子动力学分析方法对聚甲基丙烯酸甲酯(PMMA)微流控芯片模内键合过程进行模拟,研究聚合物界面分子的运动规律以及键合过程中界面结合能的变化规律,分析芯片键合强度的形成机制;利用拉伸测试法测试不同工艺环境下芯片的键合强度,分析工艺参数对键合强度的影响。研究结果表明:聚合物芯片键合强度的形成是界面分子扩散和吸附共同作用的结果。适当增加键合压力,可以显著提升键合强度,并缩短键合时间;键合温度和键合时间的提升,能够增加键合界面间分子的相互扩散,提高界面分子间的作用力,从而提高键合强度。键合温度达到聚合物材料的玻璃转化温度,键合压力能够增加键合界面的接触面积,并持续一定的键合时间,芯片可获得较高的键合强度。

With molecular dynamics analytical method, the in-mold bonding process of polymethyl methacrylate（PMMA） microfluidic chip was simulated. The molecules movement and the binding energy in the polymer interface were researched to analyze formation mechanisms of bonding strength of chips. The experiments of tensile tests were carried out to study the impact of process parameters on the bonding strength. The results show that the formation of bonding strength is the result of molecular diffusion and adsorption in the polymer interface. An appropriate increase in the bonding pressure can significantly improve the bonding strength and shorten the bonding time. Raising the bonding temperature and the bonding time can enhance the interdiffusion of molecules in the bonding interface, which can improve the interaction force of interfacial molecules and make bonding strength increase. When bonding temperature is in the vicinity of the glass transition temperature of polymer material, the bonding pressure applied for a period of time can increase the contact area at the bonding interface, and higher bonding strength of polymer chips can be obtained.