为了提高聚合物微流控芯片的键合效率,以聚甲基丙烯酸甲酯(PMMA)微流控芯片为对象,以微型注塑机为平台,研究了聚合物模内键合方法。利用注塑机提供的合模力作为键合力,利用模温机提供键合温度,选择异丙醇作为辅助溶剂,借助溶剂溶解特性来降低模内键合中的键合温度和压力。在30~70℃,用测量显微镜和台阶仪测试分析了不同键合温度条件下,辅助溶剂对芯片的表面形貌和微通道结构的影响;利用辅助溶剂进行模内键合实验,用电子万能实验机测试了芯片的键合强度,对模内键合工艺参数进行了优化。结果表明:异丙醇对键合质量的影响与键合温度、键合时间有关,在较高温度下会使芯片产生皲裂、微沟槽变形和堵塞;在键合温度为35℃,键合时间为5min时,芯片的表面质量和微沟槽形貌较完整,键合强度不小于2.64MPa。
To improve the bonding efficiency of microfluidic chips,an in-mold bonding method is researched by taking a Polymethyl Methacrylate(PMMA) microfluidic chip as an research object and a micro injection machine as a working platform.Clamping forces and bonding temperatures are provided by the micro injection machine and a mold temperature machine.Isopropanol is selected as assistant solvent to reduce the bonding temperature and bonding pressure with its solubility.At 30 ℃ to 70 ℃,a microscope and a step profiler are used to analyze the influence of assistant solvent on surface morphologies and micro channel structures of chips at different temperatures.An in-mold bonding experiment is operated with the assistant solvent,then the electric universal testing machine is utilized to measure the bonding strength and to optimize the process parameters.Experimental results illustrate that the influence of isopropanol on bonding quality is related with the bonding temperature and bonding period.The surfaces of chips chap and the micro grooves become deformed or block at higher temperatures.The surface quality and morphologies of micro grooves are correspondingly improved when the bonding temperature is 35 ℃,the bonding time is 5 min,and the bonding strength is no less than 2.64 MPa.