The triboelectric effect (also known as triboelectric charging) is a type of contact electrification on which certain materials become electrically charged after they come into frictional contact with a different material. Rubbing glass with fur, or a plastic comb through the hair, can build up triboelectricity. Most everyday static electricity is triboelectric. The polarity and strength of the charges produced differ according to the materials, surface roughness, temperature, strain, and other properties.
The triboelectric effect is not very predictable, and only broad generalizations can be made. Amber, for example, can acquire an electric charge by contact and separation (or friction) with a material like wool. This property was first recorded by Thales of Miletus. The word "electricity" is derived from William Gilbert's initial coinage, "electra", which originates in the Greek word for amber, ?lektron. The prefix tribo- (Greek for ‘rub’) refers to ‘friction’, as in tribology. Other examples of materials that can acquire a significant charge when rubbed together include glass rubbed with silk, and hard rubber rubbed with fur.
A very familiar example could be the rubbing of a plastic pen on a sleeve of almost any typical material like cotton, wool, polyester and the various mixtures generally in use for clothes nowadays. Such an electrified pen would readily attract and pick up small cm size pieces of paper when the pen approaches. Also such a pen will repel a similarly electrified pen. This repulsion is readily detectable in the sensitive set up of hanging both pens on threads and setting them nearby one another. Such experiments readily lead to the theory of two types of quantifiable electric charge one being effectively the negative of the other and a simple sum respecting signs gives the total charge. Note the electrostatic attraction of the charged plastic pen to neutral uncharged pieces of paper (for example) is due to temporary charge separation (electric polarisation or dipole moment) of electric charges within the paper (or perhaps alignments of permanent molecular or atomic electric dipoles). Note that a net force then arises as the slightly nearer charges of the dipole get attracted more strongly in the nonuniform field from the pen which diminishes with distance. In a uniform electric field for example inside parallel capacitor plates temporary polarisation would occur in the small pieces of paper but with zero net attraction.
The triboelectric effect is now considered to be related to the phenomenon of adhesion, where two materials composed of different molecules tend to stick together because of attraction between the different molecules.citation needed While adhesion is not a chemical bond between atoms, there is an exchange of electrons between the different types of molecules, resulting in an electrostatic attraction between the molecules that holds them together. Physical separation of materials that are adhered together results in friction between the materials. Because the electron transfer between molecules in the different materials is not immediately reversible, the excess electrons in one type of molecule remain left behind, while a deficit of electrons occurs in the other. Thus, a material can develop a positive or negative charge (see also static electricity) that dissipates after the materials separate. Wikipedia, Triboelectric Effect
See Also
Static Electricity
The Ox and the Chamois
Triboelectric series
Triboelectric effect
triboluminescence