低温空气等离子体改性PDMS的研究

为了改善聚二甲基硅氧烷（PDMS）的亲水性和稳定其电渗性能,采用空气微波等离子体在低温条件下对其表面进行改性。利用原子力显微镜（AFM）、X射线光电子能谱（XPS）及静态接触角对处理前后的PDMS进行分析。经空气微波等离子体处理3min后,PDMS的亲水性得到极大的改善,水在其表面的接触角接近零度。XPS结果表明：处理后PDMS表面形成SiOx薄层;AFM显示空气等离子体处理对PDMS的表面没有损伤。与文献报道的高、中真空氧等离子体处理方法相比,亲水效果基本一致,却大幅度降低了对设备真空系统的要求,并缩短了操作时间,节约了成本。最佳处理条件为：微波为100W,腔体内气压为1.0kPa,空气的流量为20sccm（1sccm=1cm3·min^-1）,时间3min。

HYDROPHILIC SURFACE MODIFICATION OF POLY (DIMETHYLSILOXAN) USING LOW-TEMPERATURE AIR MICROWAVE PLASMA

In order to improve the hydrophilicity of Poly （dimethylsiloxane） （PDMS） and steady its electroosmotic flow （EOF） properties, the air plasma generated by microwave was chosen to treat PDMS. Analysis was conducted with AFM, XPS, and contact angle before and after plasma treatment. After being treated for only 3 min, the static contact angle of PDMS almost changed to zero, which shows the hydrophilicity of PDMS is improved. As times flies, the hydrophilic surface turned to hydrophobic gradually. The XPS result indicates the modification of the PDMS to a silica-like surface （SiO,） and AFM result shows that the air plasma treatment does not change the surface morphology of the PDMS. Compared to the reported procedures using oxygen plasma treatment under high and meditlte vacuum, this approach needs equipment with simple vacuum system, and also it has a higher efficiency. The best treating conditions are as follows： the microwave power is 100 W, the total pressure in the chamber is kept at 1.0 kPa, and the flow rate of air is 20 sccm （1 sccm= 1 cm3- min^-1）.