Friction at nanopillared polymer surfaces beyond Amontons' laws: Stick-slip amplitude coefficient (SSAC) and multiparametric nanotribological properties
Friction at nanopillared polymer surfaces beyond Amontons' laws: Stick-slip amplitude coefficient (SSAC) and multiparametric nanotribological properties
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DOI：
10.1016/j.jcis.2020.09.038
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发表时间：
2021-02-01
影响因子：
9.9
通讯作者：
Su, Bo
中科院分区：
文献类型：
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作者：
Ishak, Mohd I.;Dobryden, Illia;Su, Bo
纳米结构聚合物表面的介电和纳米力学性质对于它们的技术和生物医学应用是重要的。在这项工作中，聚（对苯二甲酸乙二醇酯）（PET）的表面与周期性分布的定义明确的纳米柱制造通过阳极氧化/压花工艺。采用Fowkes酸碱法测定了纳米柱表面的表观表面能，并采用扫描电子显微镜（SEM）和原子力显微镜（AFM）对纳米柱的表面形貌进行了表征。使用胶体探针原子力显微镜（CP-AFM）的二氧化硅微粒和这些表面之间的正常和横向力进行定量。摩擦-载荷关系遵循Amonton第一定律，摩擦系数与纳米柱高度呈线性关系。此外，所有的纳米柱表面表现出明显的摩擦不稳定性相比，平滑的滑动摩擦环上的平面控制。进行粘滑振幅系数（SSAC）分析，我们发现摩擦不稳定性和纳米柱密度，拉脱力和粘附功之间的相关性。我们已经总结了依赖于这样的纳米柱化的表面上的纳米摩擦学性能的五个相关参数，即拉脱力f（p），Amontons的摩擦系数μ，RMS粗糙度R-q，粘滑振幅摩擦系数SSAC，并在雷达图中的基板和水之间的粘附功W-adh。虽然证明了纳米柱聚合物表面的摩擦行为的复杂性，我们的研究结果表明，多参数纳米结构表面的纳米摩擦学性能的分析应该超越经典的阿蒙顿定律，与SSAC更代表的摩擦性能相比，摩擦系数。(C)2020爱思唯尔公司All rights reserved.
Frictional and nanomechanical properties of nanostructured polymer surfaces are important to their technological and biomedical applications. In this work, poly(ethylene terephthalate) (PET) surfaces with a periodic distribution of well-defined nanopillars were fabricated through an anodization/embossing process. The apparent surface energy of the nanopillared surfaces was evaluated using the Fowkes acid-base approach, and the surface morphology was characterized using scanning electron microscope (SEM) and atomic force microscope (AFM). The normal and lateral forces between a silica microparticle and these surfaces were quantified using colloidal probe atomic force microscopy (CP-AFM). The friction-load relationship followed Amonton's first law, and the friction coefficient appeared to scale linearly with the nanopillar height. Furthermore, all the nanopillared surfaces showed pronounced frictional instabilities compared to the smooth sliding friction loop on the flat control. Performing the stick-slip amplitude coefficient (SSAC) analysis, we found a correlation between the frictional instabilities and the nanopillars density, pull-off force and work of adhesion. We have summarised the dependence of the nanotribological properties on such nanopillared surfaces on five relevant parameters, i.e. pull-off force f(p), Amontons' friction coefficient mu, RMS roughness R-q, stick-slip amplitude friction coefficient SSAC, and work of adhesion between the substrate and water W-adh in a radar chart. Whilst demonstrating the complexity of the frictional behaviour of nanopillared polymer surfaces, our results show that analyses of multiparametric nanotribological properties of nanostructured surfaces should go beyond classic Amontons' laws, with the SSAC more representative of the frictional properties compared to the friction coefficient. (C) 2020 Elsevier Inc. All rights reserved.