When two materials of different composition are rubbed together, one will lose electrons to the other. This process is called frictional electrification.
The imbalance is generated by the loss or gain of electrons, these particles are lighter and are far from the atomic nucleus , so their displacement occurs more simply. Protons are heavy particles that occupy the atomic nucleus, in electrification a body never loses or gains protons.
A body will be positively electrified when it loses electrons and the number of protons will become greater. Upon receiving electrons, a body will be negatively electrified .
Electrification by friction
The simplest way to electrify a body is to rub it with a material of different composition . When friction is generated, electrons will leave one of the bodies, the one that loses electrons will be positively charged, and the one that gains negative charges will be negatively charged.
The triboelectric series is a table that indicates whether bodies will be positive or negative after friction. Each material will lose electrons if it is rubbed with any other material that is lower in the table.
According to the reduced table above, if the glass is rubbed with paper, it will acquire a positive charge, while the paper will receive electrons, becoming negatively charged.
The greater the distance between the elements in the triboelectric series, the greater the electrification , i.e. rubbing dry human skin with Teflon will generate much more static electricity than rubbing dry human skin with glass.