Quantifying the contact electrification of aerosolized insulating particles

The contact electrification of aerosolized micron-scale oxide particles has been investigated experimentally and the size and composition dependence determined. The net charge acquired by particles contacting the aerosolizer was seen to increase linearly with their surface area. A physically meaningful model based upon electron transfer has been applied leading to a predictive expression for the total particle surface charge concentration generated (σ) dependent on the absolute generalized relative electronegativity (χAGR); σ = aχAGR − b, where a = 4.7 e/μm2/V, b = −27 e/μm2 and χAGR is obtained by knowing the composition of the two contacting surfaces. The influence of relative humidity and particle cohesion on the contact electrification process was investigated. A maximum surface charge concentration of around 100 e/μm2 was found, in agreement with previous work.