Institute of Science and Technology Austria (ISTA), Lab Building West, Am Campus 1, 3400 Klosterneuburg, Austria.
Phys Rev Lett. 2023 Mar 3;130(9):098202. doi: 10.1103/PhysRevLett.130.098202.
Models for same-material contact electrification in granular media often rely on a local charge-driving parameter whose spatial variations lead to a stochastic origin for charge exchange. Measuring the charge transfer from individual granular spheres after contacts with substrates of the same material, we find instead a "global" charging behavior, coherent over the sample's whole surface. Cleaning and baking samples fully resets charging magnitude and direction, which indicates the underlying global parameter is not intrinsic to the material, but acquired from its history. Charging behavior is randomly and irreversibly affected by changes in relative humidity, hinting at a mechanism where adsorbates, in particular, water, are fundamental to the charge-transfer process.
在颗粒介质中，同种材料接触带电的模型通常依赖于局部电荷驱动参数，其空间变化导致电荷交换具有随机性。在与同一种材料的基底接触后，我们测量了来自单个颗粒球体的电荷转移，发现了一种“整体”充电行为，在整个样品表面上具有一致性。彻底清洁和烘烤样品可完全重置充电幅度和方向，这表明基础整体参数不是材料固有的，而是从其历史中获得的。充电行为会随机且不可逆地受到相对湿度变化的影响，这表明吸附物（特别是水）是电荷转移过程的基础。
