Measurement of time-dependent adhesion between a polymer film and a flat indenter tip
Measurement of time-dependent adhesion between a polymer film and a flat indenter tip
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DOI：
10.1088/0022-3727/41/7/074023
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发表时间：
2008-04-07
影响因子：
3.4
通讯作者：
Earmme, Y. Y.
中科院分区：
文献类型：
--
作者：
Choi, S. T.;Lee, S. R.;Earmme, Y. Y.
本文重新讨论了刚性基底上弹性薄膜的平面压痕问题，得到了简单形式的力-深度关系。利用所得到的力-深度关系，将Kendall的弹性粘附平衡理论推广到了平面尖端与可压缩弹性薄膜之间的粘附。因此，在剥离的时刻，从弹性膜的扁平尖端的粘附的热力学功表示在拉脱力，弹性常数和几何参数。值得注意的是，如果粘弹性损失仅限于脱粘的工艺区域，则所获得的弹性膜的关系对于粘弹性膜仍然有效。这使得研究粘弹性聚合物膜的时间依赖性粘附成为可能。用金刚石平头对SU-8薄膜进行了压痕实验，结果表明Kendall理论的推广形式正确地补偿了薄膜厚度对粘附功的影响。压痕结果还表明，粘附功是强烈依赖于卸载速度的尖端，而压痕深度和停留时间的粘附功只有很小的影响。
We revisited an elasticity problem of flat indentation on an elastic film bonded to a rigid substrate and obtained the force-depth relation in a simple form. With the obtained force-depth relation, Kendall's elastic equilibrium theory of adhesion was extended to the adhesion between a flat tip and a compressible elastic film. Thus, the thermodynamic work of adhesion at the moment of debonding of a flat tip from an elastic film was expressed in terms of pull-off force, elastic constants and geometric parameters. It is worth noting that the obtained relation for elastic films is still valid for viscoelastic films if viscoelastic losses are limited to the process zone of debonding. This makes it possible to study the time-dependent adhesion of viscoelastic polymer films. Indentation experiments with a flat diamond tip were performed on SU-8 films, and the results verified that the extended form of Kendall's theory correctly compensates the effect of the finite thickness of the films on the work of adhesion. The indentation results also showed that the work of adhesion is strongly dependent on the unloading velocity of the tip, while indentation depth and dwell time have only minor effects on the work of adhesion.