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双层聚合物薄膜的有序褶皱行为

Oriented Tunable Wrinkling in Polymer Bilayer Films

【作者】 钱维仙;

【导师】 权新军;

【作者基本信息】 吉林大学 , 分析化学, 2007, 硕士

【摘要】 本论文主要研究了双层聚合物薄膜聚苯乙烯(polystyrene(PS))和聚乙烯吡咯烷酮(poly(vinyl pyrrolidone)(PVP))在水蒸汽环境下,由带沟道的软模板聚二甲基硅氧烷(PDMS)诱导薄膜表面形成高有序而又可调性的褶皱行为。当PVP遇到水蒸汽时,该聚合物薄膜立即失去它的固有机械弹性,继而转变成粘流态,这种形态的突然转变导致了杨氏模量的急剧变化,使得薄膜内部积聚起大量的应变力,最终导致表面形成褶皱形变。通过控制PDMS的形状,有效的控制了应力的产生方向,即水汽在PVP薄膜层的扩散方向,从而得到有序的形貌:1.长方形的模板得到垂直于沟道方向的褶皱;2.等腰直角三角形的模板得到与沟道方向倾斜45°的褶皱。另外,通过分别改变基层和上层的薄膜厚度,我们可以得到远小于(小一个数量级)模板沟道的褶皱形貌。并且,褶皱周期尺寸的改变是随两者膜厚乘积的指数倍递增,即λ~(hPShPVP)1/2。

【Abstract】 We report the formation of highly oriented wrinkling on the surface of the bilayer (polystyrene (PS)/poly(vinyl pyrrolidone) (PVP)) confined by a polydimethylsiloxane (PDMS) mold in a water vapor environment. When PVP is subjected to water vapor, the polymer loses its mechanical rigidity and changes to a viscous state, which leads to a dramatic change in Young’s modulus. This change generates the amount of strain in the bilayer to induce the wrinkling. With a shape-controlled mold, we can get the ordered wrinkles perfectly perpendicular or leaned 45°to the channel orientation of the mold because the orientation of the resultant force changes with the process of water diffusion which drives the surface to form the wrinkling. Additionally, we can get much smaller wrinkles than the stripe spacing of PDMS mold about one order. The wrinkle period changes with the power index of about 0.5 for various value of the multiplication product of the film thicknesses of the two layers, namelyλ~(hPShPVP)1/2.

【关键词】 双层聚合物薄膜; 水蒸汽; 诱导; 褶皱; 有序性; 膜厚;
【Key words】 polymer bilayer; water vapor; wrinkling; order; thickness;
  • 【网络出版投稿人】 吉林大学
  • 【网络出版年期】2007年 03期
  • 【分类号】O484
  • 【下载频次】230
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