Gouveia Rubia F, Galembeck Fernando
Institute of Chemistry, University of Campinas-UNICAMP, P.O. Box 6154, 13083-970 Campinas, SP, Brazil.
J Am Chem Soc. 2009 Aug 19;131(32):11381-6. doi: 10.1021/ja900704f.
Kelvin force microscopy measurements on films of noncrystalline silica and aluminum phosphate particles reveal complex electrostatic potential patterns that change irreversibly as the relative humidity changes within an electrically shielded and grounded environment. Potential adjacent to the particle surfaces is always negative and potential gradients in excess of +/-10 MV/m are found parallel to the film surface. These results verify the following hypothesis: the atmosphere is a source and sink of electrostatic charges in dielectrics, due to the partition of OH(-) and H(+) ions associated to water adsorption. Neither contact, tribochemical or electrochemical ion or electron injection are needed to change the charge state of the noncrystalline hydrophilic solids used in this work.
对非晶态二氧化硅和磷酸铝颗粒薄膜进行的开尔文力显微镜测量显示，在电屏蔽和接地环境中，随着相对湿度的变化，会出现复杂的静电势模式，且这种变化是不可逆的。颗粒表面附近的电势始终为负，并且在与薄膜表面平行的方向上发现了超过+/-10 MV/m的电势梯度。这些结果证实了以下假设：由于与水吸附相关的OH(-)和H(+)离子的分配，大气是电介质中静电荷的来源和汇。改变本研究中使用的非晶态亲水性固体的电荷状态，既不需要接触、摩擦化学或电化学离子或电子注入。
