Contact Electrification and Adhesion Between Dissimilar Materials

• Published in: Science (American Association for the Advancement of Science) Vol. 256; no. 5055; pp. 362 - 364
• Main Authors: Horn, Roger G., Smith, Douglas T.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for the Advancement of Science 17.04.1992; American Association for the Advancement of Science; The American Association for the Advancement of Science
• Subjects: Adhesion; Adhesion (Surface chemistry); Charge density; Chemistry; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electricity; Electrification; Electrodes; Electrometers; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport in interface structures; Electrostatics; Exact sciences and technology; Mica; Micrometers; Nitrogen; Physics; Reprography; Silver; Attraction interaction; Mean free path; Dielectric materials; Solid solid interface; Spontaneous; Elastic deformation; Experimental study; Adhesion; Inorganic compound; Charge density; Energy gap; Silicon Oxides; Electrostatic electrification; Charge transfer; Mica
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.256.5055.362

Simultaneous measurements of surface force and surface charge demonstrate strong attraction due to the spontaneous transfer of electrical charge from one smooth insulator (mica) to another (silica) as a result of simple, nonsliding contact in dry nitrogen. The measured surface charge densities are 5 to 20 millicoulombs per square meter after contact. The work required to separate the charged surfaces is typically 6 to 9 joules per square meter, comparable to the fracture energies of ionic-covalent materials. Observation of partial gas discharges when the surfaces are approximately 1 micrometer apart gives valuable insight into the charge separation processes underlying static electrical phenomena in general.