Effect Of Pressure And Temperature On Contact Electrification Due To Glass Plate Contact

Contact electrification means the charge transport between two surfaces after contact.Although it has been found for thousands years. But many basic questions did not resolve due to complexity and uncertainty. Electrification mechanism is not clear up to now. To understand electrification mechanism, the most important task is finding ’drive force’ of charge between identical materials. In this thesis, we focus on the effect of contact force and temperature on contact electrification. The main work is as follows:1. An instrument is designed which can measure contact electrification. The instrument is comprised of a set of crank-link mechanism to realize contacting and separating of two samples under a certain load and a faraday cylinder to induce the charge produced from contacting and an electrometer to show value. The set of equipment is installed in a sealed glass box, and iron gauze is tricked on the wall to shield external electric field. By using this equipment, we can measure temperature, moisture, contact time and contact force.2. An experiment study of no-slip asymmetrical contact electrification produced by two silica glass plates with identical chemical property under different loads. The loading modes including distributed load and concentrate load. The results indicate that, for a single contact, the glass plate can be positively electrified or negatively electrified. For multiple contacts, both the average amounts of the positive charges and the negative charges increase as the load increases. The amount of electrified charge depends on load force and the length excess between two contacted glass plates, by comparing which with the average in-plane strain, it reveals the contact electrification is highly related to in-plane strain of contact surface.3. The effect of temperature on glass contact electrification is studied through the experiment. The results show that contact charge first increases and then decreases with increasing of temperature. We think this phenomenon result from the effect of temperature on material surface moisture, which changes the spread of charge when two samples are contacting. By comparing contact charge produced from same area samples and contact charge produced from different area samples, it is found that asymmetrical contact is the main effect rather than temperature.