Xiao Zuyao, Simmchen Juliane, Pagonabarraga Ignacio, De Corato Marco
Freigeist Group, Physical Chemistry, Technische Universität Dresden, Dresden 01069, Germany.
Pure and Applied Chemistry, University of Strathclyde, Glasgow G11XL, U.K.
Nano Lett. 2025 May 14;25(19):7975-7980. doi: 10.1021/acs.nanolett.5c01567. Epub 2025 Apr 29.
In order to move toward realistic applications by extending active matter propulsion reactions beyond the classical catalytic hydrogen peroxide decomposition, we investigate the self-propulsion mechanism of Janus particles. To address the influences of ionic species, we investigate Janus particles driven by a galvanic exchange reaction that consumes and produces ions on one hemisphere. Our galvanophoretic experiments in the regime of thin Debye layers confirm that even the simplest models in active matter are still full of important surprises. We find a logarithmic speed dependence on the fuel concentration, which cannot be explained using the classic ionic self-diffusiophoretic framework. Instead, an approach based on the Poisson-Nernst-Planck equations yields a better agreement with the experiments. We attribute the discrepancy between the two models to the breakdown of two key hypotheses of the ionic self-diffusiophoretic approach.
为了通过将活性物质推进反应扩展到经典的催化过氧化氢分解之外，朝着实际应用迈进，我们研究了Janus粒子的自推进机制。为了研究离子种类的影响，我们研究了由在一个半球上消耗和产生离子的电偶极交换反应驱动的Janus粒子。我们在薄德拜层区域进行的电泳实验证实，即使是活性物质中最简单的模型仍然充满了重要的惊喜。我们发现速度对燃料浓度呈对数依赖关系，这无法用经典的离子自扩散电泳框架来解释。相反，基于泊松-能斯特-普朗克方程的方法与实验结果更吻合。我们将这两种模型之间的差异归因于离子自扩散电泳方法的两个关键假设的失效。
