Tribogeneration
Tribogeneration refers to the electrical charge generated from friction between two materials or objects rubbing together. When materials rub against each other and separate, electrons pass from one material to the other.
Neutrally charged materials have an equal amount of protons (positive charge) and electrons (negative charge). Electrically charged materials are created when two neutrally charged materials come in contact and separate; one material will give an electron to the other leaving one material with a positive charge and the other with a negative charge.
The amount of charge generated depends on various factors such as relative humidity, speed of separation, and type of material. Some materials such as leather will generate a low charge. Other materials such as polyester will generate a high charge. Even though we think of materials as objects, liquids, and gasses can also generate electrostatic charges.