Kelvin probe force microscopy study on nanotriboelectrification

Nanotriboelectrification is studied by a Kelvin probe force microscopy (KFM)-based method. The electrostatic potentials produced by the friction between the atomic force microscope tips and the substrates are recorded with KFM and the electric quantity is calculated. Charge sign reversal is found when different loaded forces are applied between tips and substrates of similar properties. A model is built to explain this phenomenon. The factors which can affect the properties of surface charges, such as loaded force, friction speed, friction time, and relative humidity are discussed in detail.