基于Au/PDMS自组装褶皱图案的实验研究

Experimental study of self-assembled wrinkle pattern based on Au/PDMS

采用离子溅射法在聚二甲基硅氧烷(PDMS)表面上沉积30~50nm厚的Au膜。基于Au与PDMS热膨胀系数的差异,有效制备出规则有序且周期可控的光栅结构和锯齿结构褶皱图案。通过局部遮挡镀膜方式,实验研究了Au膜厚度及PDMS表面特征结构对褶皱图案的影响规律。研究发现特征结构为圆形时,褶皱图案以圆形特征结构为中心,沿径向向周围辐射并逐渐形成分叉,从而获得稳定的褶皱周期,Au膜中的应力与圆的径向垂直。特征结构为微沟槽时,褶皱垂直于微沟槽的边缘,微沟槽内的褶皱方向一致且保持很好的周期稳定性。对Au/PDMS系统进行有限元非线性屈曲分析,结果表明,随着膜厚的增加,褶皱的周期随之增大,与实验结果相吻合。

Au film with thickness of 30~50 nm is deposited on the polydimethylsiloxane(PDMS)surface by ion sputtering approach.Based on the difference of thermal expansion coefficient between Au and PDMS,regularly ordered and periodically controllable wrinkle patterns with grating structure and serration structure are effectively fabricated.The influences of Au film thickness and feature structure of the PDMS on wrinkle morphology are experimentally studied by means of local shielding coating.It is found that when the feature structure is circular,the wrinkle pattern centered on the feature structure and radiated along the radial direction.Then,the wrinkle gradually bifurcated to make its period stable.The direction of the stress in the Au film is perpendicular to the radial direction of the circle.In addition,when the feature structure is a microgroove,the wrinkles with a consistent direction and a stable period is perpendicular to the edge of the micro-groove.Finite element method is employed to conduct a nonlinear buckling analysis of the Au/PDMS system.The simulation results show that the period of wrinkles increased with the increase of the Au film thickness,which is consistent with the experimental results.