ISO (The International Organization for Standardization)

A list of materials arranged so that one can become positively charged when separated from one farther down the list, or negatively charged when separated from one farther up the list. Note: The series' main utility is to indicate likely resultant charge polarities after triboelectric generation. However, this series is derived from specially prepared and cleaned materials tested in very controlled conditions. In everyday circumstances, materials reasonably close to one another in the series can produce charge polarities opposite to that expected. This series is only a guide.