接触法和非接触法作为两种常用的聚合物薄膜相对介电常数测量方法,在其测量过程中电极边缘效应是不可避免的误差来源.但电极边缘效应引起的误差难以量化,为解决该问题,利用COMSOL仿真软件对三电极结构进行建模仿真,分别得到接触法和非接触法中变电容法的电极边缘效应误差,并进行对比分析.结果表明:变电容法的电极边缘效应远大于接触法的电极边缘效应.以电极边缘效应误差不高于0.50%为标准,当薄膜厚度小于40 μm时,接触法的电极边缘效应可忽略不计,而对于变电容法只有薄膜厚度小于30 μm,其电极边缘效应才可忽略不计.
Contact method and non-contact method are two commonly used methods to measure relative dielectric constant of polymer films,and the electrode edge effect is one of the unavoidable errors in the measurement process.However,the error caused by the electrode edge effect is difficult to quantify.In order to solve this problem,COMSOL simulation software was used to model and simulate the three-electrode structure,and the errors caused by the electrode edge effect in the contact method and the variable capacitance method of non-contact method were obtained and compared respectively.The results show that the electrode edge effect of the variable capacitance method is much greater than that of the contact method.Taking the edge effect less than 0.50%as the standard,when the film thickness is less than 40 μm,the electrode edge effect of the contact method can be ignored,while for the variable capacitance method,only the film thickness is less than 30 μm,the electrode edge effect can only be ignored.