Pandey Rakesh K, Ao Chi Kit, Lim Weichun, Sun Yajuan, Di Xin, Nakanishi Hideyuki, Soh Siowling
Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore.
Department of Macromolecular Science and Engineering, Graduate School of Science and Technology, Kyoto Institute of Technology, Matsugasaki, Kyoto 606-8585, Japan.
ACS Cent Sci. 2020 May 27;6(5):704-714. doi: 10.1021/acscentsci.9b01108. Epub 2020 Mar 27.
The amount of charge of a material has always been regarded as a property (or state) of materials and can be measured precisely and specifically. This study describes for the first time a fundamental physical-chemical phenomenon in which the amount of charge of a material is actually a variable-it depends on the shape of the material. Materials are shown to have continuously variable and reversible ranges of charge states by changing their shapes. The phenomenon was general for different shapes, transformations, materials, atmospheric conditions, and methods of charging. The change in charge was probably due to a dynamic exchange of charge from the material to the surrounding atmosphere as the shape changed via the reversible ionization and deposition of air molecules. Similar changes in charge were observed for self-actuating materials that changed their shapes autonomously. This fundamental relationship between geometry and electrostatics via chemistry is important for the broad range of applications related to the charge of flexible materials.
材料的电荷量一直被视为材料的一种属性（或状态），并且可以精确且具体地进行测量。本研究首次描述了一种基本的物理化学现象，即材料的电荷量实际上是一个变量——它取决于材料的形状。通过改变形状，材料被证明具有连续可变且可逆的电荷状态范围。对于不同的形状、转变、材料、大气条件和充电方法，该现象具有普遍性。电荷的变化可能是由于随着形状通过空气分子的可逆电离和沉积而改变时，电荷从材料到周围大气的动态交换所致。对于能自主改变形状的自驱动材料，也观察到了类似的电荷变化。这种通过化学作用在几何形状与静电学之间的基本关系，对于与柔性材料电荷相关的广泛应用而言至关重要。
