The effects of surface heterogeneities on bubble–particle interactions have received little attention although heterogeneities are common for varieties of substance surfaces. In this work, heterogeneous surfaces consisting of discrete hydrophilic dots on a hydrophobic background were fabricated. The interactions between air bubbles and heterogeneous surfaces with different hydrophilic area fractions were investigated using a high-sensitivity microbalance coupled with a high-speed video camera. It was found that the snap-in, maximum adhesion, and pull-off forces increased as the hydrophilic area fraction decreased. These experimental results were compared with the calculated interaction forces. The comparison between experimental results and the calculated interaction forces showed that the normalized contact line length (δ) should be considered in the calculation of the snap-in force, and its value was between 1 and the δ value corresponding to the maximum pinning strength. In contrast, δ = 1 is more appropriate for the calculation of maximum adhesion force, indicating that the corrugations in the three-phase contact line could be neglected. These findings demonstrate that discrete hydrophilic defects make bubble–surface attachment difficult but have nearly no effect on bubble–surface detachment. Better understanding of the interactions between air bubbles and heterogeneous surfaces potential offers a new thought to control the bubble–particle interactions using appropriately design of particle surfaces.

中文翻译：

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表面异质性对气泡与异质表面相互作用的影响

尽管异质性对于各种物质表面很常见，但表面异质性对气泡-粒子相互作用的影响却很少受到关注。在这项工作中，制造了由疏水背景上的离散亲水点组成的异质表面。使用与高速摄像机耦合的高灵敏度微量天平研究了气泡和具有不同亲水面积分数的异质表面之间的相互作用。发现随着亲水面积分数的降低，咬合力、最大粘附力和拉脱力增加。这些实验结果与计算的相互作用力进行了比较。实验结果与计算的相互作用力比较表明，在计算咬合力时应考虑归一化的接触线长度（δ），其值在1到最大钉扎强度对应的δ值之间。相比之下，δ = 1 更适合计算最大附着力，表明三相接触线中的波纹可以忽略不计。这些发现表明，离散的亲水性缺陷使气泡-表面的附着变得困难，但对气泡-表面的分离几乎没有影响。更好地理解气泡和异质表面电位之间的相互作用为使用适当设计的粒子表面来控制气泡-粒子相互作用提供了一种新思路。