Effect of relative humidity on the peeling behavior of a thin film on a rigid substrate.
Effect of relative humidity on the peeling behavior of a thin film on a rigid substrate.
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DOI：
10.1103/physreve.94.032801
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发表时间：
2016-09
期刊：
影响因子：
--
通讯作者：
Zhilong Peng;Cong Wang;Yazheng Yang;Shaohua Chen
中科院分区：
文献类型：
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作者：
Zhilong Peng;Cong Wang;Yazheng Yang;Shaohua Chen
受潮湿环境中壁虎粘附的启发，建立了改进的肯德尔模型，以研究相对湿度对粘附在刚性基材上的薄膜界面剥离行为的影响。当湿度低于90%时，吸附在基材表面的单层水分子在界面处产生强烈的分离压力。结果，薄膜和基板之间的稳态剥离力显着增强。当湿度大于90%时，水分子凝结成水滴。根据薄膜和基材的表面润湿性，此时建立了四种不同的剥离模型。研究发现，与经典肯德尔模型（即干剥离模型）预测的稳态剥离力相比，稳态剥离力受到水弯月面的复杂影响，水毛细管现象会增强或减弱稳态剥离力。值得注意的是，在润湿过渡附近，四个模型的剥离力可以减小到相同，这意味着四个剥离模型可以连续地从一个模型过渡到另一个模型。本模型作为经典 Kendall 模型的扩展，不仅有助于理解潮湿环境中壁虎的粘附力，而且还有助于分析实际应用中薄膜-基材系统的界面行为。
Inspired by gecko adhesion in humid environments, a modified Kendall's model is established in order to investigate the effect of relative humidity on the interfacial peeling behavior of a thin film adhering on a rigid substrate. When the humidity is less than 90%, a monolayer of water molecules adsorbed on the substrate surface induces a strong disjoining pressure at the interface. As a result, the steady-state peel-off force between the thin film and substrate is significantly enhanced. When the humidity is greater than 90%, water molecules condense into water droplets. Four different peeling models are established on this occasion, depending on the surface wettability of the film and substrate. It is found that the steady-state peel-off force is influenced by the water meniscus in a complicated manner, which is either enhanced or reduced by the water capillarity comparing to that predicted by the classical Kendall's model, i.e., a dry peeling model. It should be noted that, at the vicinity of the wetting transition, the peel-off force of the four models can be reduced to an identical one, which means the four peeling models can transit from one to another continuously. The present model, as an extension of the classical Kendall's one, should be useful not only for understanding gecko adhesion in humid environments, but also for analyzing interface behaviors of a film-substrate system in real applications.