Giorgi Francesco, Coglitore Diego, Curran Judith M, Gilliland Douglas, Macko Peter, Whelan Maurice, Worth Andrew, Patterson Eann A
Faculty of Science and Engineering, University of Liverpool, Liverpool, L69 3GH, United Kingdom.
CNR Nanotec, Lecce, 73100, Italy.
Sci Rep. 2019 Sep 3;9(1):12689. doi: 10.1038/s41598-019-48754-5.
Van der Waals and electrostatic interactions are the dominant forces acting at the nanoscale and they have been reported to directly influence a range of phenomena including surface adhesion, friction, and colloid stability but their contribution on nanoparticle diffusion dynamics is still not clear. In this study we evaluated experimentally the changes in the diffusion coefficient of nanoparticles as a result of varying the magnitude of Van der Waals and electrostatic forces. We controlled the magnitude of these forces by varying the ionic strength of a salt solution, which has been shown to be a parameter that directly controls the forces, and found by tracking single nanoparticles dispersed in solutions with different salt molarity that the diffusion of nanoparticles increases with the magnitude of the electrostatic forces and Van der Waals forces. Our results demonstrate that these two concurrently dynamic forces play a pivotal role in driving the diffusion process and must be taken into account when considering nanoparticle behaviour.
范德华力和静电力是在纳米尺度起主导作用的力，据报道它们会直接影响一系列现象，包括表面粘附、摩擦和胶体稳定性，但它们对纳米颗粒扩散动力学的贡献仍不明确。在本研究中，我们通过实验评估了由于改变范德华力和静电力的大小而导致的纳米颗粒扩散系数的变化。我们通过改变盐溶液的离子强度来控制这些力的大小，盐溶液的离子强度已被证明是直接控制这些力的一个参数，并且通过跟踪分散在不同盐摩尔浓度溶液中的单个纳米颗粒发现，纳米颗粒的扩散随着静电力和范德华力大小的增加而增加。我们的结果表明，这两种同时存在的动态力在驱动扩散过程中起着关键作用，在考虑纳米颗粒行为时必须予以考虑。
