PDMS薄膜与CR39光学树脂不可逆封接方法研究

Irreversible Bonding Research of PDMS Membrane with CR39 Optical Resin

目的为了提高PDMS薄膜与CR39光学树脂表面间的不可逆封接性能,拓展光学材料在微流控领域的应用空间。方法研究了PDMS薄膜和CR39光学树脂两种待封接表面氧化改性和化学接枝等多种表面改性处理的原理及方法,试验测试了不同改性处理后待封接材料红外光谱及其表面接触角α的变化,进而反映了材料表面润湿特性的变化,搭建了微流控芯片封接强度测试试验平台,测试了不同试验条件下封接后微流控光学芯片样本的封接强度。结果表面氧化和化学接枝不同改性处理后,PDMS薄膜和CR39光学树脂表面的接触角α均明显减小。采用氧等离子+HEMA化学接枝组合改性处理后,两个待封接表面的接触角α分别可以长期稳定在50°和60°左右,保持良好的润湿特性。采用氧等离子清洗+APTES化学接枝组合改性处理并完成封接后,两个封接面间会形成致密的Si—O—Si聚合层,芯片封接强度最高,可达975 kPa。结论不同表面改性处理方法能够不同程度降低PDMS薄膜和CR39光学树脂待封接表面的接触角α,改善润湿特性,氧等离子+APTES化学接枝组合改性处理为上述两个待封接表面间的最优不可逆封接方法,能够大大增加封接面间的封接强度,有效提高微流控光学芯片的可靠性。

In order to improve the irreversible bonding characteristics of PDMS membrane with CR39 optical resin,and further expand the application space in microfluidic field of the optical material,the principle and process of various surface modification methods such as surface oxidation and chemical grafting are studied.The changes of IR spectra and surface contact angleα,which also present the change of the surface wetting property of PDMS membrane and CR39 optical resin,are tested by experiments.The experimental platform for bonding strength test is built,the bonding strength of the microfluidic optical chip samples under different test conditions is tested.The experimental results show that,after surface oxidation and chemical graft modification,the contact anglesαof PDMS membrane and CR39 optical resin decrease obviously.The contact anglesαof the two surfaces can be respectively stabilized at about 50°and 60°for a long time after the oxygen plasma&HEMA chemical graft combined modification.After the oxygen plasma&APTES combined modification,a dense Si—O—Si polymerization layer is formed between the bonded surfaces,and the chip bonding strength is the highest,up to 975 kPa.Therefore,it can be found that,different surface modification treatments can reduce the contact angleαof the surfaces to be bonded and enhance the wettability to varying degrees,oxygen plasma&APTES chemical graft combined modification is adopted as the optimal irreversible bonding method,which can greatly increase the bonding strength between the two bonded surfaces and effectively improve the reliability of the microfluidic optical chips.