Effect of surface coverage of a glass pipe by small particles on the triboelectrification of glucose powder

This paper presents the results of an experimental study on the triboelectrification of glucose powder in a glass pipe, and the role of smaller particles of different material mixed with a main phase. Mixtures of different concentrations were charged by sliding them down into the Faraday cup via a glass pipe. The influence of sticking to the inner surface of the pipe was examined with a microscope equipped with camera and an image analysis program. Smaller particles at the pipe surface partly change the glucose–glass contacts to the glucose–adhered powder contacts and this has a significant effect on the sign and the amount of transferred charge. The relative coverage of the glass pipe by small particles can be used as a measure of the charging ability of an additive, and can also give information regarding the sufficient amount of additive which would lead to neutral charge.