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arXiv 2202.09629cond-mat.softcond-mat.other
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用于流体界面吸附监测的旋转微球

Rotating Micro-Spheres for Adsorption Monitoring at a Fluid Interface

J. Martín-Roca, M. Jiménez, F. Ortega, C. Calero, Ch. Valeriani, R. G. Rubio, F. Martínez-Pedrero

摘要:

假设:一系列的现象,如乳化和乳化稳定性,泡沫形成或液体蒸发,都与吸附胶体颗粒的动力学密切相关。阐明隐含的机制是正确设计许多不同类型材料的关键。实验:在流体界面附近被迫旋转的微球表现出旋转平移的流体动力学机制,一旦颗粒突出界面,该机制就受到毛细管扭矩的阻碍。在这些条件下,在移动球的比例的时间演变提供了一个直接的描述的吸附动力学,而颗粒加速度\deceleration的显微镜监测通知吸附\desorption动力学。在这项工作中,所提出的策略被施加在空气/水界面加载带负电荷的球形磁性颗粒,被迫旋转的旋转磁场的作用。调查结果:所提出的方法使吸附/解吸动力学过程的最早阶段,当检测到一小部分颗粒的解吸,以及估计近似值的吸附/解吸常数。所得结果表明,一价盐或阳离子(阴离子)表面活性剂的添加促进(抑制)吸附和颗粒之间永久键的形成。

英文摘要:

Hypothesis: A broad range of phenomena, such as emulsification and emulsion stability, foam formation or liquid evaporation, are closely related to the dynamics of adsorbing colloidal particles. Elucidation of the mechanisms implied is key to a correct design of many different types of materials. Experiments: Microspheres forced to rotate near a fluid interface exhibit a roto-translational hydrodynamic mechanism that is hindered by capillary torques as soon as the particles protrude the interface. Under these conditions, the time evolution in the ratio of moving spheres provides a direct description of the adsorption kinetics, while microscopy monitoring of particle acceleration\deceleration informs about the adsorption\desorption dynamics. In this work, the proposed strategy is applied at an air/water interface loaded with spherical magnetic particles negatively charged, forced to rotate by the action of a rotating magnetic field. Findings: The proposed method enables the adsorption/desorption dynamics to be followed during the earliest phase of the process, when desorption of a small fraction of particles is detected, as well as to estimate approximated values of the adsorption/desorption constants. The results obtained show that the addition of a monovalent salt or a cationic (anionic) surfactant promotes (inhibits) both adsorption and formation of permanent bonds between particles.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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