Contact electrification, also known as triboelectric charging, is the process by which two materials come into contact and exchange electrons, resulting in a buildup of electrostatic charge on the surfaces of the materials.
When two materials with different electronegativities come into contact, electrons from the more electron-donating material will transfer to the more electron-accepting material. This creates an imbalance of positive and negative charges on the surfaces of the materials, resulting in a buildup of static electricity.
The type of materials involved, their surface properties, and the amount of contact and friction between the materials can all influence the degree of contact electrification. Humidity and temperature can also play a role in the amount of static charge buildup.
Some common examples of contact electrification include rubbing a balloon on your hair to make it stick to the wall, shuffling your feet on a carpet and then touching a doorknob to create a shock, or rubbing a plastic comb on a wool sweater and using it to pick up small pieces of paper.
Contact electrification is used in various practical applications such as electrostatic painting, electrostatic precipitation in air purifiers, and the operation of photocopiers and laser printers. It is also studied in the field of triboelectric nanogenerators, which aim to harvest energy from contact electrification for sustainable power generation.
