An electrostatic series is a list of materials that are more likely to attract a negative charge when friction is applied to them. An electrostatic series is the negative part of a triboelectric series, which includes positive charges as well.
Electrostatic series are used to measure how the polarity of an object will change when it comes into contact with another object. They are arranged with weaker negative charges at the top of the list and stronger negative tendencies at the bottom. Two common top entries into an electrostatic series are wood and skin, and two common bottom entries are teflon and ebonite. As an example, wood coming into contact with ebonite would have a tendency to gain more electrons and negative charge.
A triboelectric series is similar to the electrostatic series but also includes materials with tendencies to gain a positive charge. Triboelectric series are used to predict how a certain material's charge will change when it comes into contact with other materials. It can also be used to find control surfaces like steel, which will not charge when in contact with something else or confer a positive or a negative charge onto another material. This knowledge has a variety of uses in industries like magnetics, insulation and textiles.