Abstract Estimating the hydrophobicity of a solid surface is important for flotation process. Measuring the contact angle or interaction force between air bubbles and a solid surface has been widely used for evaluating the hydrophobicity of surfaces. However, the correlation between the contact angle and interaction force was not be fully explained because contact angle was measured on a macroscale surface and interaction force was measured on a microscale surface (ranging nm2 – μm2) using atomic force microscopy. In this study, we directly measured the macroscale surface – air bubble interaction force in terms of attachment force and detachment energy. We then correlated our measured attachment force and detachment energy values with the static contact angle of specimen surface. The attachment force (Fa) and detachment energy in phase 2 (E2) represented the hydrophobicity of specimen surface. And Fa and Ed in phase 2 were found to have an exponential relationship until 90° of the surface contact angle.

中文翻译：

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固体表面与气泡相互作用力的直接测量：相互作用力与接触角的关系

摘要 估算固体表面的疏水性对于浮选过程很重要。测量气泡与固体表面之间的接触角或相互作用力已被广泛用于评估表面的疏水性。然而，接触角和相互作用力之间的相关性并未得到充分解释，因为接触角是在宏观表面上测量的，而相互作用力是使用原子力显微镜在微观表面（范围为 nm2 - μm2）上测量的。在这项研究中，我们直接测量了宏观表面 - 气泡在附着力和脱离能方面的相互作用力。然后，我们将测量的附着力和脱离能量值与试样表面的静态接触角相关联。阶段 2 (E2) 中的附着力 (Fa) 和脱离能代表样品表面的疏水性。并且发现第 2 阶段中的 Fa 和 Ed 具有指数关系，直到表面接触角为 90°。